Refactor "spack buildcache" command (#27776)

This PR is meant to move code with "business logic" from `spack.cmd.buildcache` to appropriate core modules[^1]. 

Modifications:
- [x] Add `spack.binary_distribution.push` to create a binary package from a spec and push it to a mirror
- [x] Add `spack.binary_distribution.install_root_node` to install only the root node of a concrete spec from a buildcache (may check the sha256 sum if it is passed in as input)
- [x] Add `spack.binary_distribution.install_single_spec` to install a single concrete spec from a buildcache
- [x] Add `spack.binary_distribution.download_single_spec` to download a single concrete spec from a buildcache to a local destination
- [x] Add `Spec.from_specfile` that construct a spec given the path of a JSON or YAML spec file
- [x] Removed logic from `spack.cmd.buildcache`
- [x] Removed calls to `spack.cmd.buildcache` in `spack.bootstrap`
- [x] Deprecate `spack buildcache copy` with a message that says it will be removed in v0.19.0

[^1]: The rationale is that commands should be lightweight wrappers of the core API, since that helps with both testing and scripting (easier mocking and no need to invoke `SpackCommand`s in a script).

11 files changed, 511 insertions, 438 deletions

diff --git a/lib/spack/spack/binary_distribution.py b/lib/spack/spack/binary_distribution.py
index 99566a23ae..01817a3abd 100644
--- a/lib/spack/spack/binary_distribution.py
+++ b/lib/spack/spack/binary_distribution.py
@@ -13,6 +13,7 @@ import sys
 import tarfile
 import tempfile
 import traceback
+import warnings
 from contextlib import closing
 
 import ruamel.yaml as yaml
@@ -27,10 +28,13 @@ import spack.config as config
 import spack.database as spack_db
 import spack.fetch_strategy as fs
 import spack.hash_types as ht
+import spack.hooks
 import spack.hooks.sbang
 import spack.mirror
 import spack.platforms
 import spack.relocate as relocate
+import spack.repo
+import spack.store
 import spack.util.file_cache as file_cache
 import spack.util.gpg
 import spack.util.spack_json as sjson
@@ -975,8 +979,11 @@ def generate_key_index(key_prefix, tmpdir=None):
                 shutil.rmtree(tmpdir)
 
 
-def build_tarball(spec, outdir, force=False, rel=False, unsigned=False,
-                  allow_root=False, key=None, regenerate_index=False):
+def _build_tarball(
+        spec, outdir,
+        force=False, relative=False, unsigned=False,
+        allow_root=False, key=None, regenerate_index=False
+):
     """
     Build a tarball from given spec and put it into the directory structure
     used at the mirror (following <tarball_directory_name>).
@@ -1044,11 +1051,11 @@ def build_tarball(spec, outdir, force=False, rel=False, unsigned=False,
     os.remove(temp_tarfile_path)
 
     # create info for later relocation and create tar
-    write_buildinfo_file(spec, workdir, rel)
+    write_buildinfo_file(spec, workdir, relative)
 
     # optionally make the paths in the binaries relative to each other
     # in the spack install tree before creating tarball
-    if rel:
+    if relative:
         try:
             make_package_relative(workdir, spec, allow_root)
         except Exception as e:
@@ -1096,7 +1103,7 @@ def build_tarball(spec, outdir, force=False, rel=False, unsigned=False,
     buildinfo = {}
     buildinfo['relative_prefix'] = os.path.relpath(
         spec.prefix, spack.store.layout.root)
-    buildinfo['relative_rpaths'] = rel
+    buildinfo['relative_rpaths'] = relative
     spec_dict['buildinfo'] = buildinfo
 
     with open(specfile_path, 'w') as outfile:
@@ -1148,6 +1155,64 @@ def build_tarball(spec, outdir, force=False, rel=False, unsigned=False,
     return None
 
 
+def nodes_to_be_packaged(specs, include_root=True, include_dependencies=True):
+    """Return the list of nodes to be packaged, given a list of specs.
+
+    Args:
+        specs (List[spack.spec.Spec]): list of root specs to be processed
+        include_root (bool): include the root of each spec in the nodes
+        include_dependencies (bool): include the dependencies of each
+            spec in the nodes
+    """
+    if not include_root and not include_dependencies:
+        return set()
+
+    def skip_node(current_node):
+        if current_node.external or current_node.virtual:
+            return True
+        return spack.store.db.query_one(current_node) is None
+
+    expanded_set = set()
+    for current_spec in specs:
+        if not include_dependencies:
+            nodes = [current_spec]
+        else:
+            nodes = [n for n in current_spec.traverse(
+                order='post', root=include_root, deptype=('link', 'run')
+            )]
+
+        for node in nodes:
+            if not skip_node(node):
+                expanded_set.add(node)
+
+    return expanded_set
+
+
+def push(specs, push_url, specs_kwargs=None, **kwargs):
+    """Create a binary package for each of the specs passed as input and push them
+    to a given push URL.
+
+    Args:
+        specs (List[spack.spec.Spec]): installed specs to be packaged
+        push_url (str): url where to push the binary package
+        specs_kwargs (dict): dictionary with two possible boolean keys, "include_root"
+            and "include_dependencies", which determine which part of each spec is
+            packaged and pushed to the mirror
+        **kwargs: TODO
+
+    """
+    specs_kwargs = specs_kwargs or {'include_root': True, 'include_dependencies': True}
+    nodes = nodes_to_be_packaged(specs, **specs_kwargs)
+
+    # TODO: This seems to be an easy target for task
+    # TODO: distribution using a parallel pool
+    for node in nodes:
+        try:
+            _build_tarball(node, push_url, **kwargs)
+        except NoOverwriteException as e:
+            warnings.warn(str(e))
+
+
 def download_tarball(spec, preferred_mirrors=None):
     """
     Download binary tarball for given package into stage area, returning
@@ -1486,6 +1551,66 @@ def extract_tarball(spec, filename, allow_root=False, unsigned=False,
             os.remove(filename)
 
 
+def install_root_node(spec, allow_root, unsigned=False, force=False, sha256=None):
+    """Install the root node of a concrete spec from a buildcache.
+
+    Checking the sha256 sum of a node before installation is usually needed only
+    for software installed during Spack's bootstrapping (since we might not have
+    a proper signature verification mechanism available).
+
+    Args:
+        spec: spec to be installed (note that only the root node will be installed)
+        allow_root (bool): allows the root directory to be present in binaries
+            (may affect relocation)
+        unsigned (bool): if True allows installing unsigned binaries
+        force (bool): force installation if the spec is already present in the
+            local store
+        sha256 (str): optional sha256 of the binary package, to be checked
+            before installation
+    """
+    package = spack.repo.get(spec)
+    # Early termination
+    if spec.external or spec.virtual:
+        warnings.warn("Skipping external or virtual package {0}".format(spec.format()))
+        return
+    elif spec.concrete and package.installed and not force:
+        warnings.warn("Package for spec {0} already installed.".format(spec.format()))
+        return
+
+    tarball = download_tarball(spec)
+    if not tarball:
+        msg = 'download of binary cache file for spec "{0}" failed'
+        raise RuntimeError(msg.format(spec.format()))
+
+    if sha256:
+        checker = spack.util.crypto.Checker(sha256)
+        msg = 'cannot verify checksum for "{0}" [expected={1}]'
+        msg = msg.format(tarball, sha256)
+        if not checker.check(tarball):
+            raise spack.binary_distribution.NoChecksumException(msg)
+        tty.debug('Verified SHA256 checksum of the build cache')
+
+    tty.msg('Installing "{0}" from a buildcache'.format(spec.format()))
+    extract_tarball(spec, tarball, allow_root, unsigned, force)
+    spack.hooks.post_install(spec)
+    spack.store.db.add(spec, spack.store.layout)
+
+
+def install_single_spec(spec, allow_root=False, unsigned=False, force=False):
+    """Install a single concrete spec from a buildcache.
+
+    Args:
+        spec (spack.spec.Spec): spec to be installed
+        allow_root (bool): allows the root directory to be present in binaries
+            (may affect relocation)
+        unsigned (bool): if True allows installing unsigned binaries
+        force (bool): force installation if the spec is already present in the
+            local store
+    """
+    for node in spec.traverse(root=True, order='post', deptype=('link', 'run')):
+        install_root_node(node, allow_root=allow_root, unsigned=unsigned, force=force)
+
+
 def try_direct_fetch(spec, full_hash_match=False, mirrors=None):
     """
     Try to find the spec directly on the configured mirrors
@@ -1937,3 +2062,73 @@ def download_buildcache_entry(file_descriptions, mirror_url=None):
             continue
 
     return False
+
+
+def download_single_spec(
+        concrete_spec, destination, require_cdashid=False, mirror_url=None
+):
+    """Download the buildcache files for a single concrete spec.
+
+    Args:
+        concrete_spec: concrete spec to be downloaded
+        destination (str): path where to put the downloaded buildcache
+        require_cdashid (bool): if False the `.cdashid` file is optional
+        mirror_url (str): url of the mirror from which to download
+    """
+    tarfile_name = tarball_name(concrete_spec, '.spack')
+    tarball_dir_name = tarball_directory_name(concrete_spec)
+    tarball_path_name = os.path.join(tarball_dir_name, tarfile_name)
+    local_tarball_path = os.path.join(destination, tarball_dir_name)
+
+    files_to_fetch = [
+        {
+            'url': [tarball_path_name],
+            'path': local_tarball_path,
+            'required': True,
+        }, {
+            'url': [tarball_name(concrete_spec, '.spec.json'),
+                    tarball_name(concrete_spec, '.spec.yaml')],
+            'path': destination,
+            'required': True,
+        }, {
+            'url': [tarball_name(concrete_spec, '.cdashid')],
+            'path': destination,
+            'required': require_cdashid,
+        },
+    ]
+
+    return download_buildcache_entry(files_to_fetch, mirror_url)
+
+
+class BinaryCacheQuery(object):
+    """Callable object to query if a spec is in a binary cache"""
+    def __init__(self, all_architectures):
+        """
+        Args:
+            all_architectures (bool): if True consider all the spec for querying,
+                otherwise restrict to the current default architecture
+        """
+        self.all_architectures = all_architectures
+
+        specs = update_cache_and_get_specs()
+
+        if not self.all_architectures:
+            arch = spack.spec.Spec.default_arch()
+            specs = [s for s in specs if s.satisfies(arch)]
+
+        self.possible_specs = specs
+
+    def __call__(self, spec, **kwargs):
+        matches = []
+        if spec.startswith('/'):
+            # Matching a DAG hash
+            query_hash = spec.replace('/', '')
+            for candidate_spec in self.possible_specs:
+                if candidate_spec.dag_hash().startswith(query_hash):
+                    matches.append(candidate_spec)
+        else:
+            # Matching a spec constraint
+            matches = [
+                s for s in self.possible_specs if s.satisfies(spec)
+            ]
+        return matches
diff --git a/lib/spack/spack/bootstrap.py b/lib/spack/spack/bootstrap.py
index 86a11db22b..ee9ec118e4 100644
--- a/lib/spack/spack/bootstrap.py
+++ b/lib/spack/spack/bootstrap.py
@@ -4,7 +4,6 @@
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 from __future__ import print_function
 
-import argparse
 import contextlib
 import fnmatch
 import functools
@@ -255,11 +254,6 @@ class _BuildcacheBootstrapper(object):
         return data
 
     def _install_by_hash(self, pkg_hash, pkg_sha256, index, bincache_platform):
-        # TODO: The local import is due to a circular import error. The
-        # TODO: correct fix for this is a refactor of the API used for
-        # TODO: binary relocation
-        import spack.cmd.buildcache
-
         index_spec = next(x for x in index if x.dag_hash() == pkg_hash)
         # Reconstruct the compiler that we need to use for bootstrapping
         compiler_entry = {
@@ -279,16 +273,18 @@ class _BuildcacheBootstrapper(object):
                     'compilers', [{'compiler': compiler_entry}]
             ):
                 spec_str = '/' + pkg_hash
-                parser = argparse.ArgumentParser()
-                spack.cmd.buildcache.setup_parser(parser)
-                install_args = [
-                    'install',
-                    '--sha256', pkg_sha256,
-                    '--only-root',
-                    '-a', '-u', '-o', '-f', spec_str
-                ]
-                args = parser.parse_args(install_args)
-                spack.cmd.buildcache.installtarball(args)
+                query = spack.binary_distribution.BinaryCacheQuery(
+                    all_architectures=True
+                )
+                matches = spack.store.find([spec_str], multiple=False, query_fn=query)
+                for match in matches:
+                    spack.binary_distribution.install_root_node(
+                        match,
+                        allow_root=True,
+                        unsigned=True,
+                        force=True,
+                        sha256=pkg_sha256
+                    )
 
     def _install_and_test(
             self, abstract_spec, bincache_platform, bincache_data, test_fn
diff --git a/lib/spack/spack/ci.py b/lib/spack/spack/ci.py
index 8d337196ce..edcca7f2ed 100644
--- a/lib/spack/spack/ci.py
+++ b/lib/spack/spack/ci.py
@@ -1412,15 +1412,26 @@ def read_cdashid_from_mirror(spec, mirror_url):
     return int(contents)
 
 
-def push_mirror_contents(env, spec, specfile_path, mirror_url, sign_binaries):
+def _push_mirror_contents(env, specfile_path, sign_binaries, mirror_url):
+    """Unchecked version of the public API, for easier mocking"""
+    unsigned = not sign_binaries
+    tty.debug('Creating buildcache ({0})'.format(
+        'unsigned' if unsigned else 'signed'))
+    hashes = env.all_hashes() if env else None
+    matches = spack.store.specfile_matches(specfile_path, hashes=hashes)
+    push_url = spack.mirror.push_url_from_mirror_url(mirror_url)
+    spec_kwargs = {'include_root': True, 'include_dependencies': False}
+    kwargs = {
+        'force': True,
+        'allow_root': True,
+        'unsigned': unsigned
+    }
+    bindist.push(matches, push_url, spec_kwargs, **kwargs)
+
+
+def push_mirror_contents(env, specfile_path, mirror_url, sign_binaries):
     try:
-        unsigned = not sign_binaries
-        tty.debug('Creating buildcache ({0})'.format(
-            'unsigned' if unsigned else 'signed'))
-        spack.cmd.buildcache._createtarball(
-            env, spec_file=specfile_path, add_deps=False,
-            output_location=mirror_url, force=True, allow_root=True,
-            unsigned=unsigned)
+        _push_mirror_contents(env, specfile_path, sign_binaries, mirror_url)
     except Exception as inst:
         # If the mirror we're pushing to is on S3 and there's some
         # permissions problem, for example, we can't just target
diff --git a/lib/spack/spack/cmd/buildcache.py b/lib/spack/spack/cmd/buildcache.py
index 380d61c66a..d6f5d63ea6 100644
--- a/lib/spack/spack/cmd/buildcache.py
+++ b/lib/spack/spack/cmd/buildcache.py
@@ -2,11 +2,11 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
-import argparse
 import os
 import shutil
 import sys
 import tempfile
+import warnings
 
 import llnl.util.tty as tty
 
@@ -40,7 +40,7 @@ def setup_parser(subparser):
     setup_parser.parser = subparser
     subparsers = subparser.add_subparsers(help='buildcache sub-commands')
 
-    create = subparsers.add_parser('create', help=createtarball.__doc__)
+    create = subparsers.add_parser('create', help=create_fn.__doc__)
     create.add_argument('-r', '--rel', action='store_true',
                         help="make all rpaths relative" +
                              " before creating tarballs.")
@@ -86,9 +86,9 @@ def setup_parser(subparser):
                               ' decide to build a cache for only the package'
                               ' or only the dependencies'))
     arguments.add_common_arguments(create, ['specs'])
-    create.set_defaults(func=createtarball)
+    create.set_defaults(func=create_fn)
 
-    install = subparsers.add_parser('install', help=installtarball.__doc__)
+    install = subparsers.add_parser('install', help=install_fn.__doc__)
     install.add_argument('-f', '--force', action='store_true',
                          help="overwrite install directory if it exists.")
     install.add_argument('-m', '--multiple', action='store_true',
@@ -102,16 +102,11 @@ def setup_parser(subparser):
     install.add_argument('-o', '--otherarch', action='store_true',
                          help="install specs from other architectures" +
                               " instead of default platform and OS")
-    # This argument is needed by the bootstrapping logic to verify checksums
-    install.add_argument('--sha256', help=argparse.SUPPRESS)
-    install.add_argument(
-        '--only-root', action='store_true', help=argparse.SUPPRESS
-    )
 
     arguments.add_common_arguments(install, ['specs'])
-    install.set_defaults(func=installtarball)
+    install.set_defaults(func=install_fn)
 
-    listcache = subparsers.add_parser('list', help=listspecs.__doc__)
+    listcache = subparsers.add_parser('list', help=list_fn.__doc__)
     arguments.add_common_arguments(listcache, ['long', 'very_long'])
     listcache.add_argument('-v', '--variants',
                            action='store_true',
@@ -121,29 +116,25 @@ def setup_parser(subparser):
                            help="list specs for all available architectures" +
                                  " instead of default platform and OS")
     arguments.add_common_arguments(listcache, ['specs'])
-    listcache.set_defaults(func=listspecs)
+    listcache.set_defaults(func=list_fn)
 
-    dlkeys = subparsers.add_parser('keys', help=getkeys.__doc__)
-    dlkeys.add_argument(
+    keys = subparsers.add_parser('keys', help=keys_fn.__doc__)
+    keys.add_argument(
         '-i', '--install', action='store_true',
         help="install Keys pulled from mirror")
-    dlkeys.add_argument(
+    keys.add_argument(
         '-t', '--trust', action='store_true',
         help="trust all downloaded keys")
-    dlkeys.add_argument('-f', '--force', action='store_true',
-                        help="force new download of keys")
-    dlkeys.set_defaults(func=getkeys)
-
-    preview_parser = subparsers.add_parser(
-        'preview',
-        help='analyzes an installed spec and reports whether '
-             'executables and libraries are relocatable'
-    )
-    arguments.add_common_arguments(preview_parser, ['installed_specs'])
-    preview_parser.set_defaults(func=preview)
+    keys.add_argument('-f', '--force', action='store_true',
+                      help="force new download of keys")
+    keys.set_defaults(func=keys_fn)
+
+    preview = subparsers.add_parser('preview', help=preview_fn.__doc__)
+    arguments.add_common_arguments(preview, ['installed_specs'])
+    preview.set_defaults(func=preview_fn)
 
     # Check if binaries need to be rebuilt on remote mirror
-    check = subparsers.add_parser('check', help=check_binaries.__doc__)
+    check = subparsers.add_parser('check', help=check_fn.__doc__)
     check.add_argument(
         '-m', '--mirror-url', default=None,
         help='Override any configured mirrors with this mirror url')
@@ -175,28 +166,28 @@ def setup_parser(subparser):
         help="Default to rebuilding packages if errors are encountered " +
              "during the process of checking whether rebuilding is needed")
 
-    check.set_defaults(func=check_binaries)
+    check.set_defaults(func=check_fn)
 
     # Download tarball and specfile
-    dltarball = subparsers.add_parser('download', help=get_tarball.__doc__)
-    dltarball.add_argument(
+    download = subparsers.add_parser('download', help=download_fn.__doc__)
+    download.add_argument(
         '-s', '--spec', default=None,
         help="Download built tarball for spec from mirror")
-    dltarball.add_argument(
+    download.add_argument(
         '--spec-file', default=None,
         help=("Download built tarball for spec (from json or yaml file) " +
               "from mirror"))
-    dltarball.add_argument(
+    download.add_argument(
         '-p', '--path', default=None,
         help="Path to directory where tarball should be downloaded")
-    dltarball.add_argument(
+    download.add_argument(
         '-c', '--require-cdashid', action='store_true', default=False,
         help="Require .cdashid file to be downloaded with buildcache entry")
-    dltarball.set_defaults(func=get_tarball)
+    download.set_defaults(func=download_fn)
 
     # Get buildcache name
     getbuildcachename = subparsers.add_parser('get-buildcache-name',
-                                              help=get_buildcache_name.__doc__)
+                                              help=get_buildcache_name_fn.__doc__)
     getbuildcachename.add_argument(
         '-s', '--spec', default=None,
         help='Spec string for which buildcache name is desired')
@@ -204,11 +195,11 @@ def setup_parser(subparser):
         '--spec-file', default=None,
         help=('Path to spec json or yaml file for which buildcache name is ' +
               'desired'))
-    getbuildcachename.set_defaults(func=get_buildcache_name)
+    getbuildcachename.set_defaults(func=get_buildcache_name_fn)
 
     # Given the root spec, save the yaml of the dependent spec to a file
     savespecfile = subparsers.add_parser('save-specfile',
-                                         help=save_specfiles.__doc__)
+                                         help=save_specfile_fn.__doc__)
     savespecfile.add_argument(
         '--root-spec', default=None,
         help='Root spec of dependent spec')
@@ -221,10 +212,10 @@ def setup_parser(subparser):
     savespecfile.add_argument(
         '--specfile-dir', default=None,
         help='Path to directory where spec yamls should be saved')
-    savespecfile.set_defaults(func=save_specfiles)
+    savespecfile.set_defaults(func=save_specfile_fn)
 
     # Copy buildcache from some directory to another mirror url
-    copy = subparsers.add_parser('copy', help=buildcache_copy.__doc__)
+    copy = subparsers.add_parser('copy', help=copy_fn.__doc__)
     copy.add_argument(
         '--base-dir', default=None,
         help='Path to mirror directory (root of existing buildcache)')
@@ -235,10 +226,10 @@ def setup_parser(subparser):
     copy.add_argument(
         '--destination-url', default=None,
         help='Destination mirror url')
-    copy.set_defaults(func=buildcache_copy)
+    copy.set_defaults(func=copy_fn)
 
     # Sync buildcache entries from one mirror to another
-    sync = subparsers.add_parser('sync', help=buildcache_sync.__doc__)
+    sync = subparsers.add_parser('sync', help=sync_fn.__doc__)
     source = sync.add_mutually_exclusive_group(required=True)
     source.add_argument('--src-directory',
                         metavar='DIRECTORY',
@@ -265,311 +256,115 @@ def setup_parser(subparser):
                       metavar='MIRROR_URL',
                       type=str,
                       help="URL of the destination mirror")
-    sync.set_defaults(func=buildcache_sync)
+    sync.set_defaults(func=sync_fn)
 
     # Update buildcache index without copying any additional packages
     update_index = subparsers.add_parser(
-        'update-index', help=buildcache_update_index.__doc__)
+        'update-index', help=update_index_fn.__doc__)
     update_index.add_argument(
         '-d', '--mirror-url', default=None, help='Destination mirror url')
     update_index.add_argument(
         '-k', '--keys', default=False, action='store_true',
         help='If provided, key index will be updated as well as package index')
-    update_index.set_defaults(func=buildcache_update_index)
-
-
-def find_matching_specs(pkgs, allow_multiple_matches=False, env=None):
-    """Returns a list of specs matching the not necessarily
-       concretized specs given from cli
+    update_index.set_defaults(func=update_index_fn)
 
-    Args:
-        pkgs (str): spec to be matched against installed packages
-        allow_multiple_matches (bool): if True multiple matches are admitted
-        env (spack.environment.Environment or None): active environment, or ``None``
-            if there is not one
 
-    Return:
-        list: list of specs
+def _matching_specs(args):
+    """Return a list of matching specs read from either a spec file (JSON or YAML),
+    a query over the store or a query over the active environment.
     """
+    env = ev.active_environment()
     hashes = env.all_hashes() if env else None
+    if args.spec_file:
+        return spack.store.specfile_matches(args.spec_file, hashes=hashes)
 
-    # List of specs that match expressions given via command line
-    specs_from_cli = []
-    has_errors = False
-    tty.debug('find_matching_specs: about to parse specs for {0}'.format(pkgs))
-    specs = spack.cmd.parse_specs(pkgs)
-    for spec in specs:
-        matching = spack.store.db.query(spec, hashes=hashes)
-        # For each spec provided, make sure it refers to only one package.
-        # Fail and ask user to be unambiguous if it doesn't
-        if not allow_multiple_matches and len(matching) > 1:
-            tty.error('%s matches multiple installed packages:' % spec)
-            for match in matching:
-                tty.msg('"%s"' % match.format())
-            has_errors = True
-
-        # No installed package matches the query
-        if len(matching) == 0 and spec is not any:
-            tty.error('{0} does not match any installed packages.'.format(
-                spec))
-            has_errors = True
-
-        specs_from_cli.extend(matching)
-    if has_errors:
-        tty.die('use one of the matching specs above')
-
-    return specs_from_cli
-
-
-def match_downloaded_specs(pkgs, allow_multiple_matches=False, force=False,
-                           other_arch=False):
-    """Returns a list of specs matching the not necessarily
-       concretized specs given from cli
-
-    Args:
-        specs: list of specs to be matched against buildcaches on mirror
-        allow_multiple_matches : if True multiple matches are admitted
-
-    Return:
-        list of specs
-    """
-    # List of specs that match expressions given via command line
-    specs_from_cli = []
-    has_errors = False
-
-    specs = bindist.update_cache_and_get_specs()
-
-    if not other_arch:
-        arch = spack.spec.Spec.default_arch()
-        specs = [s for s in specs if s.satisfies(arch)]
-
-    for pkg in pkgs:
-        matches = []
-        tty.msg("buildcache spec(s) matching %s \n" % pkg)
-        for spec in sorted(specs):
-            if pkg.startswith('/'):
-                pkghash = pkg.replace('/', '')
-                if spec.dag_hash().startswith(pkghash):
-                    matches.append(spec)
-            else:
-                if spec.satisfies(pkg):
-                    matches.append(spec)
-        # For each pkg provided, make sure it refers to only one package.
-        # Fail and ask user to be unambiguous if it doesn't
-        if not allow_multiple_matches and len(matches) > 1:
-            tty.error('%s matches multiple downloaded packages:' % pkg)
-            for match in matches:
-                tty.msg('"%s"' % match.format())
-            has_errors = True
-
-        # No downloaded package matches the query
-        if len(matches) == 0:
-            tty.error('%s does not match any downloaded packages.' % pkg)
-            has_errors = True
-
-        specs_from_cli.extend(matches)
-    if has_errors:
-        tty.die('use one of the matching specs above')
-
-    return specs_from_cli
-
-
-def _createtarball(env, spec_file=None, packages=None, add_spec=True,
-                   add_deps=True, output_location=os.getcwd(),
-                   signing_key=None, force=False, make_relative=False,
-                   unsigned=False, allow_root=False, rebuild_index=False):
-    if spec_file:
-        with open(spec_file, 'r') as fd:
-            specfile_contents = fd.read()
-            tty.debug('createtarball read specfile contents:')
-            tty.debug(specfile_contents)
-            if spec_file.endswith('.json'):
-                s = Spec.from_json(specfile_contents)
-            else:
-                s = Spec.from_yaml(specfile_contents)
-            package = '/{0}'.format(s.dag_hash())
-            matches = find_matching_specs(package, env=env)
-
-    elif packages:
-        matches = find_matching_specs(packages, env=env)
-
-    elif env:
-        matches = [env.specs_by_hash[h] for h in env.concretized_order]
+    if args.specs:
+        constraints = spack.cmd.parse_specs(args.specs)
+        return spack.store.find(constraints, hashes=hashes)
 
-    else:
-        tty.die("build cache file creation requires at least one" +
-                " installed package spec, an active environment," +
-                " or else a path to a json or yaml file containing a spec" +
-                " to install")
-    specs = set()
+    if env:
+        return [env.specs_by_hash[h] for h in env.concretized_order]
 
-    mirror = spack.mirror.MirrorCollection().lookup(output_location)
-    outdir = url_util.format(mirror.push_url)
+    tty.die("build cache file creation requires at least one" +
+            " installed package spec, an active environment," +
+            " or else a path to a json or yaml file containing a spec" +
+            " to install")
 
-    msg = 'Buildcache files will be output to %s/build_cache' % outdir
-    tty.msg(msg)
 
-    if matches:
-        tty.debug('Found at least one matching spec')
+def _concrete_spec_from_args(args):
+    spec_str, specfile_path = args.spec, args.spec_file
 
-    for match in matches:
-        tty.debug('examining match {0}'.format(match.format()))
-        if match.external or match.virtual:
-            tty.debug('skipping external or virtual spec %s' %
-                      match.format())
-        else:
-            lookup = spack.store.db.query_one(match)
-
-            if not add_spec:
-                tty.debug('skipping matching root spec %s' % match.format())
-            elif lookup is None:
-                tty.debug('skipping uninstalled matching spec %s' %
-                          match.format())
-            else:
-                tty.debug('adding matching spec %s' % match.format())
-                specs.add(match)
-
-            if not add_deps:
-                continue
-
-            tty.debug('recursing dependencies')
-            for d, node in match.traverse(order='post',
-                                          depth=True,
-                                          deptype=('link', 'run')):
-                # skip root, since it's handled above
-                if d == 0:
-                    continue
-
-                lookup = spack.store.db.query_one(node)
-
-                if node.external or node.virtual:
-                    tty.debug('skipping external or virtual dependency %s' %
-                              node.format())
-                elif lookup is None:
-                    tty.debug('skipping uninstalled depenendency %s' %
-                              node.format())
-                else:
-                    tty.debug('adding dependency %s' % node.format())
-                    specs.add(node)
-
-    tty.debug('writing tarballs to %s/build_cache' % outdir)
+    if not spec_str and not specfile_path:
+        tty.error('must provide either spec string or path to YAML or JSON specfile')
+        sys.exit(1)
 
-    for spec in specs:
-        tty.debug('creating binary cache file for package %s ' % spec.format())
+    if spec_str:
         try:
-            bindist.build_tarball(spec, outdir, force, make_relative,
-                                  unsigned, allow_root, signing_key,
-                                  rebuild_index)
-        except bindist.NoOverwriteException as e:
-            tty.warn(e)
+            constraints = spack.cmd.parse_specs(spec_str)
+            spec = spack.store.find(constraints)[0]
+            spec.concretize()
+        except SpecError as spec_error:
+            tty.error('Unable to concretize spec {0}'.format(spec_str))
+            tty.debug(spec_error)
+            sys.exit(1)
 
+        return spec
 
-def createtarball(args):
-    """create a binary package from an existing install"""
+    return Spec.from_specfile(specfile_path)
 
-    # restrict matching to current environment if one is active
-    env = ev.active_environment()
 
-    output_location = None
+def create_fn(args):
+    """create a binary package and push it to a mirror"""
     if args.directory:
-        output_location = args.directory
+        push_url = spack.mirror.push_url_from_directory(args.directory)
 
-        # User meant to provide a path to a local directory.
-        # Ensure that they did not accidentally pass a URL.
-        scheme = url_util.parse(output_location, scheme='<missing>').scheme
-        if scheme != '<missing>':
-            raise ValueError(
-                '"--directory" expected a local path; got a URL, instead')
+    if args.mirror_name:
+        push_url = spack.mirror.push_url_from_mirror_name(args.mirror_name)
 
-        # User meant to provide a path to a local directory.
-        # Ensure that the mirror lookup does not mistake it for a named mirror.
-        output_location = 'file://' + output_location
-
-    elif args.mirror_name:
-        output_location = args.mirror_name
-
-        # User meant to provide the name of a preconfigured mirror.
-        # Ensure that the mirror lookup actually returns a named mirror.
-        result = spack.mirror.MirrorCollection().lookup(output_location)
-        if result.name == "<unnamed>":
-            raise ValueError(
-                'no configured mirror named "{name}"'.format(
-                    name=output_location))
-
-    elif args.mirror_url:
-        output_location = args.mirror_url
-
-        # User meant to provide a URL for an anonymous mirror.
-        # Ensure that they actually provided a URL.
-        scheme = url_util.parse(output_location, scheme='<missing>').scheme
-        if scheme == '<missing>':
-            raise ValueError(
-                '"{url}" is not a valid URL'.format(url=output_location))
-    add_spec = ('package' in args.things_to_install)
-    add_deps = ('dependencies' in args.things_to_install)
-
-    _createtarball(env, spec_file=args.spec_file, packages=args.specs,
-                   add_spec=add_spec, add_deps=add_deps,
-                   output_location=output_location, signing_key=args.key,
-                   force=args.force, make_relative=args.rel,
-                   unsigned=args.unsigned, allow_root=args.allow_root,
-                   rebuild_index=args.rebuild_index)
+    if args.mirror_url:
+        push_url = spack.mirror.push_url_from_mirror_url(args.mirror_url)
 
+    matches = _matching_specs(args)
 
-def installtarball(args):
+    msg = 'Pushing binary packages to {0}/build_cache'.format(push_url)
+    tty.msg(msg)
+    specs_kwargs = {
+        'include_root': 'package' in args.things_to_install,
+        'include_dependencies': 'dependencies' in args.things_to_install
+    }
+    kwargs = {
+        'key': args.key,
+        'force': args.force,
+        'relative': args.rel,
+        'unsigned': args.unsigned,
+        'allow_root': args.allow_root,
+        'regenerate_index': args.rebuild_index
+    }
+    bindist.push(matches, push_url, specs_kwargs, **kwargs)
+
+
+def install_fn(args):
     """install from a binary package"""
     if not args.specs:
-        tty.die("build cache file installation requires" +
-                " at least one package spec argument")
-    pkgs = set(args.specs)
-    matches = match_downloaded_specs(pkgs, args.multiple, args.force,
-                                     args.otherarch)
+        tty.die("a spec argument is required to install from a buildcache")
 
+    query = bindist.BinaryCacheQuery(all_architectures=args.otherarch)
+    matches = spack.store.find(args.specs, multiple=args.multiple, query_fn=query)
     for match in matches:
-        install_tarball(match, args)
-
+        bindist.install_single_spec(
+            match,
+            allow_root=args.allow_root,
+            unsigned=args.unsigned,
+            force=args.force
+        )
 
-def install_tarball(spec, args):
-    s = Spec(spec)
-    if s.external or s.virtual:
-        tty.warn("Skipping external or virtual package %s" % spec.format())
-        return
 
-    # This argument is used only for bootstrapping specs without signatures,
-    # since we need to check the sha256 of each tarball
-    if not args.only_root:
-        for d in s.dependencies(deptype=('link', 'run')):
-            tty.msg("Installing buildcache for dependency spec %s" % d)
-            install_tarball(d, args)
-
-    package = spack.repo.get(spec)
-    if s.concrete and package.installed and not args.force:
-        tty.warn("Package for spec %s already installed." % spec.format())
-    else:
-        tarball = bindist.download_tarball(spec)
-        if tarball:
-            if args.sha256:
-                checker = spack.util.crypto.Checker(args.sha256)
-                msg = ('cannot verify checksum for "{0}"'
-                       ' [expected={1}]')
-                msg = msg.format(tarball, args.sha256)
-                if not checker.check(tarball):
-                    raise spack.binary_distribution.NoChecksumException(msg)
-                tty.debug('Verified SHA256 checksum of the build cache')
-
-            tty.msg('Installing buildcache for spec %s' % spec.format())
-            bindist.extract_tarball(spec, tarball, args.allow_root,
-                                    args.unsigned, args.force)
-            spack.hooks.post_install(spec)
-            spack.store.db.add(spec, spack.store.layout)
-        else:
-            tty.die('Download of binary cache file for spec %s failed.' %
-                    spec.format())
-
-
-def listspecs(args):
+def list_fn(args):
     """list binary packages available from mirrors"""
-    specs = bindist.update_cache_and_get_specs()
+    try:
+        specs = bindist.update_cache_and_get_specs()
+    except bindist.FetchCacheError as e:
+        tty.error(e)
 
     if not args.allarch:
         arch = spack.spec.Spec.default_arch()
@@ -587,19 +382,17 @@ def listspecs(args):
     display_specs(specs, args, all_headers=True)
 
 
-def getkeys(args):
+def keys_fn(args):
     """get public keys available on mirrors"""
     bindist.get_keys(args.install, args.trust, args.force)
 
 
-def preview(args):
-    """Print a status tree of the selected specs that shows which nodes are
-    relocatable and which might not be.
-
-    Args:
-        args: command line arguments
+def preview_fn(args):
+    """analyze an installed spec and reports whether executables
+    and libraries are relocatable
     """
-    specs = find_matching_specs(args.specs, allow_multiple_matches=True)
+    constraints = spack.cmd.parse_specs(args.specs)
+    specs = spack.store.find(constraints, multiple=True)
 
     # Cycle over the specs that match
     for spec in specs:
@@ -608,7 +401,7 @@ def preview(args):
         print(spec.tree(status_fn=spack.relocate.is_relocatable))
 
 
-def check_binaries(args):
+def check_fn(args):
     """Check specs (either a single spec from --spec, or else the full set
     of release specs) against remote binary mirror(s) to see if any need
     to be rebuilt.  This command uses the process exit code to indicate
@@ -616,7 +409,7 @@ def check_binaries(args):
     one of the indicated specs needs to be rebuilt.
     """
     if args.spec or args.spec_file:
-        specs = [get_concrete_spec(args)]
+        specs = [_concrete_spec_from_args(args)]
     else:
         env = spack.cmd.require_active_env(cmd_name='buildcache')
         env.concretize()
@@ -643,34 +436,7 @@ def check_binaries(args):
         configured_mirrors, specs, args.output_file, args.rebuild_on_error))
 
 
-def download_buildcache_files(concrete_spec, local_dest, require_cdashid,
-                              mirror_url=None):
-    tarfile_name = bindist.tarball_name(concrete_spec, '.spack')
-    tarball_dir_name = bindist.tarball_directory_name(concrete_spec)
-    tarball_path_name = os.path.join(tarball_dir_name, tarfile_name)
-    local_tarball_path = os.path.join(local_dest, tarball_dir_name)
-
-    files_to_fetch = [
-        {
-            'url': [tarball_path_name],
-            'path': local_tarball_path,
-            'required': True,
-        }, {
-            'url': [bindist.tarball_name(concrete_spec, '.spec.json'),
-                    bindist.tarball_name(concrete_spec, '.spec.yaml')],
-            'path': local_dest,
-            'required': True,
-        }, {
-            'url': [bindist.tarball_name(concrete_spec, '.cdashid')],
-            'path': local_dest,
-            'required': require_cdashid,
-        },
-    ]
-
-    return bindist.download_buildcache_entry(files_to_fetch, mirror_url)
-
-
-def get_tarball(args):
+def download_fn(args):
     """Download buildcache entry from a remote mirror to local folder.  This
     command uses the process exit code to indicate its result, specifically,
     a non-zero exit code indicates that the command failed to download at
@@ -685,54 +451,30 @@ def get_tarball(args):
         tty.msg('No download path provided, exiting')
         sys.exit(0)
 
-    spec = get_concrete_spec(args)
-    result = download_buildcache_files(spec, args.path, args.require_cdashid)
+    spec = _concrete_spec_from_args(args)
+    result = bindist.download_single_spec(
+        spec, args.path, require_cdashid=args.require_cdashid
+    )
 
     if not result:
         sys.exit(1)
 
 
-def get_concrete_spec(args):
-    spec_str = args.spec
-    spec_yaml_path = args.spec_file
-
-    if not spec_str and not spec_yaml_path:
-        tty.msg('Must provide either spec string or path to ' +
-                'yaml to concretize spec')
-        sys.exit(1)
-
-    if spec_str:
-        try:
-            spec = find_matching_specs(spec_str)[0]
-            spec.concretize()
-        except SpecError as spec_error:
-            tty.error('Unable to concrectize spec {0}'.format(args.spec))
-            tty.debug(spec_error)
-            sys.exit(1)
-
-        return spec
-
-    with open(spec_yaml_path, 'r') as fd:
-        return Spec.from_yaml(fd.read())
-
-
-def get_buildcache_name(args):
+def get_buildcache_name_fn(args):
     """Get name (prefix) of buildcache entries for this spec"""
-    spec = get_concrete_spec(args)
+    spec = _concrete_spec_from_args(args)
     buildcache_name = bindist.tarball_name(spec, '')
-
     print('{0}'.format(buildcache_name))
 
-    sys.exit(0)
-
 
-def save_specfiles(args):
+def save_specfile_fn(args):
     """Get full spec for dependencies, relative to root spec, and write them
     to files in the specified output directory.  Uses exit code to signal
     success or failure.  An exit code of zero means the command was likely
     successful.  If any errors or exceptions are encountered, or if expected
     command-line arguments are not provided, then the exit code will be
-    non-zero."""
+    non-zero.
+    """
     if not args.root_spec and not args.root_specfile:
         tty.msg('No root spec provided, exiting.')
         sys.exit(1)
@@ -759,12 +501,15 @@ def save_specfiles(args):
     sys.exit(0)
 
 
-def buildcache_copy(args):
+def copy_fn(args):
     """Copy a buildcache entry and all its files from one mirror, given as
     '--base-dir', to some other mirror, specified as '--destination-url'.
     The specific buildcache entry to be copied from one location to the
     other is identified using the '--spec-file' argument."""
-    # TODO: This sub-command should go away once #11117 is merged
+    # TODO: Remove after v0.18.0 release
+    msg = ('"spack buildcache copy" is deprecated and will be removed from '
+           'Spack starting in v0.19.0')
+    warnings.warn(msg)
 
     if not args.spec_file:
         tty.msg('No spec yaml provided, exiting.')
@@ -839,7 +584,7 @@ def buildcache_copy(args):
         shutil.copyfile(cdashid_src_path, cdashid_dest_path)
 
 
-def buildcache_sync(args):
+def sync_fn(args):
     """ Syncs binaries (and associated metadata) from one mirror to another.
     Requires an active environment in order to know which specs to sync.
 
@@ -973,7 +718,7 @@ def update_index(mirror_url, update_keys=False):
         bindist.generate_key_index(keys_url)
 
 
-def buildcache_update_index(args):
+def update_index_fn(args):
     """Update a buildcache index."""
     outdir = '.'
     if args.mirror_url:
diff --git a/lib/spack/spack/cmd/ci.py b/lib/spack/spack/cmd/ci.py
index b8ed1fb27d..4c2ee5f25d 100644
--- a/lib/spack/spack/cmd/ci.py
+++ b/lib/spack/spack/cmd/ci.py
@@ -397,8 +397,12 @@ def ci_rebuild(args):
             tty.debug('Getting {0} buildcache from {1}'.format(
                 job_spec_pkg_name, matching_mirror))
             tty.debug('Downloading to {0}'.format(build_cache_dir))
-            buildcache.download_buildcache_files(
-                job_spec, build_cache_dir, False, matching_mirror)
+            bindist.download_single_spec(
+                job_spec,
+                build_cache_dir,
+                require_cdashid=False,
+                mirror_url=matching_mirror
+            )
 
         # Now we are done and successful
         sys.exit(0)
@@ -553,8 +557,8 @@ def ci_rebuild(args):
         # per-PR mirror, if this is a PR pipeline
         if buildcache_mirror_url:
             spack_ci.push_mirror_contents(
-                env, job_spec, job_spec_yaml_path, buildcache_mirror_url,
-                sign_binaries)
+                env, job_spec_yaml_path, buildcache_mirror_url, sign_binaries
+            )
 
             if cdash_build_id:
                 tty.debug('Writing cdashid ({0}) to remote mirror: {1}'.format(
@@ -568,8 +572,8 @@ def ci_rebuild(args):
         # prefix is set)
         if pipeline_mirror_url:
             spack_ci.push_mirror_contents(
-                env, job_spec, job_spec_yaml_path, pipeline_mirror_url,
-                sign_binaries)
+                env, job_spec_yaml_path, pipeline_mirror_url, sign_binaries
+            )
 
             if cdash_build_id:
                 tty.debug('Writing cdashid ({0}) to remote mirror: {1}'.format(
diff --git a/lib/spack/spack/mirror.py b/lib/spack/spack/mirror.py
index 0d51c26ce2..f6e5d38091 100644
--- a/lib/spack/spack/mirror.py
+++ b/lib/spack/spack/mirror.py
@@ -644,6 +644,35 @@ def _add_single_spec(spec, mirror, mirror_stats):
         mirror_stats.error()
 
 
+def push_url_from_directory(output_directory):
+    """Given a directory in the local filesystem, return the URL on
+    which to push binary packages.
+    """
+    scheme = url_util.parse(output_directory, scheme='<missing>').scheme
+    if scheme != '<missing>':
+        raise ValueError('expected a local path, but got a URL instead')
+    mirror_url = 'file://' + output_directory
+    mirror = spack.mirror.MirrorCollection().lookup(mirror_url)
+    return url_util.format(mirror.push_url)
+
+
+def push_url_from_mirror_name(mirror_name):
+    """Given a mirror name, return the URL on which to push binary packages."""
+    mirror = spack.mirror.MirrorCollection().lookup(mirror_name)
+    if mirror.name == "<unnamed>":
+        raise ValueError('no mirror named "{0}"'.format(mirror_name))
+    return url_util.format(mirror.push_url)
+
+
+def push_url_from_mirror_url(mirror_url):
+    """Given a mirror URL, return the URL on which to push binary packages."""
+    scheme = url_util.parse(mirror_url, scheme='<missing>').scheme
+    if scheme == '<missing>':
+        raise ValueError('"{0}" is not a valid URL'.format(mirror_url))
+    mirror = spack.mirror.MirrorCollection().lookup(mirror_url)
+    return url_util.format(mirror.push_url)
+
+
 class MirrorError(spack.error.SpackError):
     """Superclass of all mirror-creation related errors."""
 
diff --git a/lib/spack/spack/spec.py b/lib/spack/spack/spec.py
index a8e3684e44..8523dd6838 100644
--- a/lib/spack/spack/spec.py
+++ b/lib/spack/spack/spec.py
@@ -1864,6 +1864,15 @@ class Spec(object):
         return sjson.dump(self.to_dict(hash), stream)
 
     @staticmethod
+    def from_specfile(path):
+        """Construct a spec from aJSON or YAML spec file path"""
+        with open(path, 'r') as fd:
+            file_content = fd.read()
+            if path.endswith('.json'):
+                return Spec.from_json(file_content)
+            return Spec.from_yaml(file_content)
+
+    @staticmethod
     def from_node_dict(node):
         spec = Spec()
         if 'name' in node.keys():
diff --git a/lib/spack/spack/store.py b/lib/spack/spack/store.py
index b0a418c7e3..1b372b848c 100644
--- a/lib/spack/spack/store.py
+++ b/lib/spack/spack/store.py
@@ -29,6 +29,7 @@ import llnl.util.tty as tty
 import spack.config
 import spack.database
 import spack.directory_layout
+import spack.error
 import spack.paths
 import spack.util.path
 
@@ -284,6 +285,75 @@ def _construct_upstream_dbs_from_install_roots(
     return accumulated_upstream_dbs
 
 
+def find(constraints, multiple=False, query_fn=None, **kwargs):
+    """Return a list of specs matching the constraints passed as inputs.
+
+    At least one spec per constraint must match, otherwise the function
+    will error with an appropriate message.
+
+    By default, this function queries the current store, but a custom query
+    function can be passed to hit any other source of concretized specs
+    (e.g. a binary cache).
+
+    The query function must accept a spec as its first argument.
+
+    Args:
+        constraints (List[spack.spec.Spec]): specs to be matched against
+            installed packages
+        multiple (bool): if True multiple matches per constraint are admitted
+        query_fn (Callable): query function to get matching specs. By default,
+            ``spack.store.db.query``
+        **kwargs: keyword arguments forwarded to the query function
+
+    Return:
+        List of matching specs
+    """
+    # Normalize input to list of specs
+    if isinstance(constraints, six.string_types):
+        constraints = [spack.spec.Spec(constraints)]
+
+    matching_specs, errors = [], []
+    query_fn = query_fn or spack.store.db.query
+    for spec in constraints:
+        current_matches = query_fn(spec, **kwargs)
+
+        # For each spec provided, make sure it refers to only one package.
+        if not multiple and len(current_matches) > 1:
+            msg_fmt = '"{0}" matches multiple packages: [{1}]'
+            errors.append(
+                msg_fmt.format(spec, ', '.join([m.format() for m in current_matches]))
+            )
+
+        # No installed package matches the query
+        if len(current_matches) == 0 and spec is not any:
+            msg_fmt = '"{0}" does not match any installed packages'
+            errors.append(msg_fmt.format(spec))
+
+        matching_specs.extend(current_matches)
+
+    if errors:
+        raise MatchError(
+            message="errors occurred when looking for specs in the store",
+            long_message='\n'.join(errors)
+        )
+
+    return matching_specs
+
+
+def specfile_matches(filename, **kwargs):
+    """Same as find but reads the query from a spec file.
+
+    Args:
+        filename (str): YAML or JSON file from which to read the query.
+        **kwargs: keyword arguments forwarded to "find"
+
+    Return:
+        List of matches
+    """
+    query = [spack.spec.Spec.from_specfile(filename)]
+    return spack.store.find(query, **kwargs)
+
+
 @contextlib.contextmanager
 def use_store(store_or_path):
     """Use the store passed as argument within the context manager.
@@ -314,3 +384,7 @@ def use_store(store_or_path):
         store = original_store
         db, layout = original_store.db, original_store.layout
         root, unpadded_root = original_store.root, original_store.unpadded_root
+
+
+class MatchError(spack.error.SpackError):
+    """Error occurring when trying to match specs in store against a constraint"""
diff --git a/lib/spack/spack/test/build_distribution.py b/lib/spack/spack/test/build_distribution.py
index 1514b3e903..042e7fe9f9 100644
--- a/lib/spack/spack/test/build_distribution.py
+++ b/lib/spack/spack/test/build_distribution.py
@@ -22,13 +22,12 @@ def test_build_tarball_overwrite(
         install(str(spec))
 
         # Runs fine the first time, throws the second time
-        spack.binary_distribution.build_tarball(spec, '.', unsigned=True)
+        spack.binary_distribution._build_tarball(spec, '.', unsigned=True)
         with pytest.raises(spack.binary_distribution.NoOverwriteException):
-            spack.binary_distribution.build_tarball(spec, '.', unsigned=True)
+            spack.binary_distribution._build_tarball(spec, '.', unsigned=True)
 
         # Should work fine with force=True
-        spack.binary_distribution.build_tarball(
-            spec, '.', force=True, unsigned=True)
+        spack.binary_distribution._build_tarball(spec, '.', force=True, unsigned=True)
 
         # Remove the tarball and try again.
         # This must *also* throw, because of the existing .spec.json file
@@ -38,4 +37,4 @@ def test_build_tarball_overwrite(
             spack.binary_distribution.tarball_name(spec, '.spack')))
 
         with pytest.raises(spack.binary_distribution.NoOverwriteException):
-            spack.binary_distribution.build_tarball(spec, '.', unsigned=True)
+            spack.binary_distribution._build_tarball(spec, '.', unsigned=True)
diff --git a/lib/spack/spack/test/cmd/ci.py b/lib/spack/spack/test/cmd/ci.py
index c17ab1b4d5..b9bf02adb2 100644
--- a/lib/spack/spack/test/cmd/ci.py
+++ b/lib/spack/spack/test/cmd/ci.py
@@ -12,8 +12,8 @@ import pytest
 from jsonschema import ValidationError, validate
 
 import spack
+import spack.binary_distribution
 import spack.ci as ci
-import spack.cmd.buildcache as buildcache
 import spack.compilers as compilers
 import spack.config
 import spack.environment as ev
@@ -897,11 +897,11 @@ spack:
             set_env_var('SPACK_COMPILER_ACTION', 'NONE')
             set_env_var('SPACK_REMOTE_MIRROR_URL', mirror_url)
 
-            def fake_dl_method(spec, dest, require_cdashid, m_url=None):
+            def fake_dl_method(spec, *args, **kwargs):
                 print('fake download buildcache {0}'.format(spec.name))
 
             monkeypatch.setattr(
-                buildcache, 'download_buildcache_files', fake_dl_method)
+                spack.binary_distribution, 'download_single_spec', fake_dl_method)
 
             ci_out = ci_cmd('rebuild', output=str)
 
@@ -970,8 +970,7 @@ spack:
             install_cmd('--keep-stage', json_path)
 
             # env, spec, json_path, mirror_url, build_id, sign_binaries
-            ci.push_mirror_contents(
-                env, concrete_spec, json_path, mirror_url, True)
+            ci.push_mirror_contents(env, json_path, mirror_url, True)
 
             ci.write_cdashid_to_mirror('42', concrete_spec, mirror_url)
 
@@ -1063,23 +1062,20 @@ spack:
 
 
 def test_push_mirror_contents_exceptions(monkeypatch, capsys):
-    def faked(env, spec_file=None, packages=None, add_spec=True,
-              add_deps=True, output_location=os.getcwd(),
-              signing_key=None, force=False, make_relative=False,
-              unsigned=False, allow_root=False, rebuild_index=False):
+    def failing_access(*args, **kwargs):
         raise Exception('Error: Access Denied')
 
-    import spack.cmd.buildcache as buildcache
-    monkeypatch.setattr(buildcache, '_createtarball', faked)
+    monkeypatch.setattr(spack.ci, '_push_mirror_contents', failing_access)
 
+    # Input doesn't matter, as wwe are faking exceptional output
     url = 'fakejunk'
-    ci.push_mirror_contents(None, None, None, url, None)
+    ci.push_mirror_contents(None, None, url, None)
 
     captured = capsys.readouterr()
     std_out = captured[0]
     expect_msg = 'Permission problem writing to {0}'.format(url)
 
-    assert(expect_msg in std_out)
+    assert expect_msg in std_out
 
 
 def test_ci_generate_override_runner_attrs(tmpdir, mutable_mock_env_path,
diff --git a/lib/spack/spack/test/database.py b/lib/spack/spack/test/database.py
index 57a03a5db9..925acc83d3 100644
--- a/lib/spack/spack/test/database.py
+++ b/lib/spack/spack/test/database.py
@@ -909,3 +909,18 @@ def test_database_works_with_empty_dir(tmpdir):
         db.query()
     # Check that reading an empty directory didn't create a new index.json
     assert not os.path.exists(db._index_path)
+
+
+@pytest.mark.parametrize('query_arg,exc_type,msg_str', [
+    (['callpath'], spack.store.MatchError, 'matches multiple packages'),
+    (['tensorflow'], spack.store.MatchError, 'does not match any')
+])
+def test_store_find_failures(database, query_arg, exc_type, msg_str):
+    with pytest.raises(exc_type) as exc_info:
+        spack.store.find(query_arg, multiple=False)
+    assert msg_str in str(exc_info.value)
+
+
+def test_store_find_accept_string(database):
+    result = spack.store.find('callpath', multiple=True)
+    assert len(result) == 3