Enable/disable bootstrapping and customize store location (#23677)

* Permit to enable/disable bootstrapping and customize store location

This PR adds configuration handles to allow enabling
and disabling bootstrapping, and to customize the store
location.

* Move bootstrap related configuration into its own YAML file

* Add a bootstrap command to manage configuration

13 files changed, 337 insertions, 11 deletions

diff --git a/etc/spack/defaults/bootstrap.yaml b/etc/spack/defaults/bootstrap.yaml
new file mode 100644
index 0000000000..78bb43f4b1
--- /dev/null
+++ b/etc/spack/defaults/bootstrap.yaml
@@ -0,0 +1,7 @@
+bootstrap:
+  # If set to false Spack will not bootstrap missing software,
+  # but will instead raise an error.
+  enable: true
+  # Root directory for bootstrapping work. The software bootstrapped
+  # by Spack is installed in a "store" subfolder of this root directory
+  root: ~/.spack/bootstrap
diff --git a/lib/spack/spack/bootstrap.py b/lib/spack/spack/bootstrap.py
index 86c3110983..96f11b631d 100644
--- a/lib/spack/spack/bootstrap.py
+++ b/lib/spack/spack/bootstrap.py
@@ -25,6 +25,7 @@ import spack.spec
 import spack.store
 import spack.user_environment as uenv
 import spack.util.executable
+import spack.util.path
 from spack.util.environment import EnvironmentModifications
 
 
@@ -216,9 +217,10 @@ def _bootstrap_config_scopes():
 
 @contextlib.contextmanager
 def ensure_bootstrap_configuration():
+    bootstrap_store_path = store_path()
     with spack.architecture.use_platform(spack.architecture.real_platform()):
         with spack.repo.use_repositories(spack.paths.packages_path):
-            with spack.store.use_store(spack.paths.user_bootstrap_store):
+            with spack.store.use_store(bootstrap_store_path):
                 # Default configuration scopes excluding command line
                 # and builtin but accounting for platform specific scopes
                 config_scopes = _bootstrap_config_scopes()
@@ -227,6 +229,23 @@ def ensure_bootstrap_configuration():
                         yield
 
 
+def store_path():
+    """Path to the store used for bootstrapped software"""
+    enabled = spack.config.get('bootstrap:enable', True)
+    if not enabled:
+        msg = ('bootstrapping is currently disabled. '
+               'Use "spack bootstrap enable" to enable it')
+        raise RuntimeError(msg)
+
+    bootstrap_root_path = spack.config.get(
+        'bootstrap:root', spack.paths.user_bootstrap_path
+    )
+    bootstrap_store_path = spack.util.path.canonicalize_path(
+        os.path.join(bootstrap_root_path, 'store')
+    )
+    return bootstrap_store_path
+
+
 def clingo_root_spec():
     # Construct the root spec that will be used to bootstrap clingo
     spec_str = 'clingo-bootstrap@spack+python'
diff --git a/lib/spack/spack/cmd/bootstrap.py b/lib/spack/spack/cmd/bootstrap.py
new file mode 100644
index 0000000000..2c95da117c
--- /dev/null
+++ b/lib/spack/spack/cmd/bootstrap.py
@@ -0,0 +1,110 @@
+# Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+import os.path
+import shutil
+
+import llnl.util.tty
+
+import spack.cmd.common.arguments
+import spack.config
+import spack.main
+import spack.util.path
+
+description = "manage bootstrap configuration"
+section = "system"
+level = "long"
+
+
+def _add_scope_option(parser):
+    scopes = spack.config.scopes()
+    scopes_metavar = spack.config.scopes_metavar
+    parser.add_argument(
+        '--scope', choices=scopes, metavar=scopes_metavar,
+        help="configuration scope to read/modify"
+    )
+
+
+def setup_parser(subparser):
+    sp = subparser.add_subparsers(dest='subcommand')
+
+    enable = sp.add_parser('enable', help='enable bootstrapping')
+    _add_scope_option(enable)
+
+    disable = sp.add_parser('disable', help='disable bootstrapping')
+    _add_scope_option(disable)
+
+    reset = sp.add_parser(
+        'reset', help='reset bootstrapping configuration to Spack defaults'
+    )
+    spack.cmd.common.arguments.add_common_arguments(
+        reset, ['yes_to_all']
+    )
+
+    root = sp.add_parser(
+        'root', help='get/set the root bootstrap directory'
+    )
+    _add_scope_option(root)
+    root.add_argument(
+        'path', nargs='?', default=None,
+        help='set the bootstrap directory to this value'
+    )
+
+
+def _enable_or_disable(args):
+    # Set to True if we called "enable", otherwise set to false
+    value = args.subcommand == 'enable'
+    spack.config.set('bootstrap:enable', value, scope=args.scope)
+
+
+def _reset(args):
+    if not args.yes_to_all:
+        msg = [
+            "Bootstrapping configuration is being reset to Spack's defaults. "
+            "Current configuration will be lost.\n",
+            "Do you want to continue?"
+        ]
+        ok_to_continue = llnl.util.tty.get_yes_or_no(
+            ''.join(msg), default=True
+        )
+        if not ok_to_continue:
+            raise RuntimeError('Aborting')
+
+    for scope in spack.config.config.file_scopes:
+        # The default scope should stay untouched
+        if scope.name == 'defaults':
+            continue
+
+        # If we are in an env scope we can't delete a file, but the best we
+        # can do is nullify the corresponding configuration
+        if (scope.name.startswith('env') and
+                spack.config.get('bootstrap', scope=scope.name)):
+            spack.config.set('bootstrap', {}, scope=scope.name)
+            continue
+
+        # If we are outside of an env scope delete the bootstrap.yaml file
+        bootstrap_yaml = os.path.join(scope.path, 'bootstrap.yaml')
+        backup_file = bootstrap_yaml + '.bkp'
+        if os.path.exists(bootstrap_yaml):
+            shutil.move(bootstrap_yaml, backup_file)
+
+
+def _root(args):
+    if args.path:
+        spack.config.set('bootstrap:root', args.path, scope=args.scope)
+
+    root = spack.config.get('bootstrap:root', default=None, scope=args.scope)
+    if root:
+        root = spack.util.path.canonicalize_path(root)
+    print(root)
+
+
+def bootstrap(parser, args):
+    callbacks = {
+        'enable': _enable_or_disable,
+        'disable': _enable_or_disable,
+        'reset': _reset,
+        'root': _root
+    }
+    callbacks[args.subcommand](args)
diff --git a/lib/spack/spack/cmd/clean.py b/lib/spack/spack/cmd/clean.py
index 273b1789ad..3b66358293 100644
--- a/lib/spack/spack/cmd/clean.py
+++ b/lib/spack/spack/cmd/clean.py
@@ -9,6 +9,7 @@ import shutil
 
 import llnl.util.tty as tty
 
+import spack.bootstrap
 import spack.caches
 import spack.cmd.common.arguments as arguments
 import spack.cmd.test
@@ -102,7 +103,7 @@ def clean(parser, args):
 
     if args.bootstrap:
         msg = 'Removing software in "{0}"'
-        tty.msg(msg.format(spack.paths.user_bootstrap_store))
-        with spack.store.use_store(spack.paths.user_bootstrap_store):
+        tty.msg(msg.format(spack.bootstrap.store_path()))
+        with spack.store.use_store(spack.bootstrap.store_path()):
             uninstall = spack.main.SpackCommand('uninstall')
             uninstall('-a', '-y')
diff --git a/lib/spack/spack/cmd/find.py b/lib/spack/spack/cmd/find.py
index f532b684bd..875c236164 100644
--- a/lib/spack/spack/cmd/find.py
+++ b/lib/spack/spack/cmd/find.py
@@ -13,6 +13,7 @@ import llnl.util.lang
 import llnl.util.tty as tty
 import llnl.util.tty.color as color
 
+import spack.bootstrap
 import spack.cmd as cmd
 import spack.cmd.common.arguments as arguments
 import spack.environment as ev
@@ -207,9 +208,10 @@ def find(parser, args):
     q_args = query_arguments(args)
     # Query the current store or the internal bootstrap store if required
     if args.bootstrap:
+        bootstrap_store_path = spack.bootstrap.store_path()
         msg = 'Showing internal bootstrap store at "{0}"'
-        tty.msg(msg.format(spack.paths.user_bootstrap_store))
-        with spack.store.use_store(spack.paths.user_bootstrap_store):
+        tty.msg(msg.format(bootstrap_store_path))
+        with spack.store.use_store(bootstrap_store_path):
             results = args.specs(**q_args)
     else:
         results = args.specs(**q_args)
diff --git a/lib/spack/spack/config.py b/lib/spack/spack/config.py
index 038a879a81..5ceaef8e7b 100644
--- a/lib/spack/spack/config.py
+++ b/lib/spack/spack/config.py
@@ -51,6 +51,7 @@ import spack.architecture
 import spack.compilers
 import spack.paths
 import spack.schema
+import spack.schema.bootstrap
 import spack.schema.compilers
 import spack.schema.config
 import spack.schema.env
@@ -74,6 +75,7 @@ section_schemas = {
     'modules': spack.schema.modules.schema,
     'config': spack.schema.config.schema,
     'upstreams': spack.schema.upstreams.schema,
+    'bootstrap': spack.schema.bootstrap.schema
 }
 
 # Same as above, but including keys for environments
diff --git a/lib/spack/spack/paths.py b/lib/spack/spack/paths.py
index 6b41049de8..76eb9dfdac 100644
--- a/lib/spack/spack/paths.py
+++ b/lib/spack/spack/paths.py
@@ -11,10 +11,10 @@ dependencies.
 """
 import os
 
-from llnl.util.filesystem import ancestor
+import llnl.util.filesystem
 
 #: This file lives in $prefix/lib/spack/spack/__file__
-prefix = ancestor(__file__, 4)
+prefix = llnl.util.filesystem.ancestor(__file__, 4)
 
 #: synonym for prefix
 spack_root = prefix
@@ -53,7 +53,6 @@ mock_packages_path = os.path.join(repos_path, "builtin.mock")
 #: User configuration location
 user_config_path = os.path.expanduser('~/.spack')
 user_bootstrap_path = os.path.join(user_config_path, 'bootstrap')
-user_bootstrap_store = os.path.join(user_bootstrap_path, 'store')
 reports_path = os.path.join(user_config_path, "reports")
 monitor_path = os.path.join(reports_path, "monitor")
 
diff --git a/lib/spack/spack/schema/bootstrap.py b/lib/spack/spack/schema/bootstrap.py
new file mode 100644
index 0000000000..0505f09003
--- /dev/null
+++ b/lib/spack/spack/schema/bootstrap.py
@@ -0,0 +1,26 @@
+# Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+"""Schema for bootstrap.yaml configuration file."""
+
+properties = {
+    'bootstrap': {
+        'type': 'object',
+        'properties': {
+            'enable': {'type': 'boolean'},
+            'root': {
+                'type': 'string'
+            },
+        }
+    }
+}
+
+#: Full schema with metadata
+schema = {
+    '$schema': 'http://json-schema.org/schema#',
+    'title': 'Spack bootstrap configuration file schema',
+    'type': 'object',
+    'additionalProperties': False,
+    'properties': properties,
+}
diff --git a/lib/spack/spack/schema/merged.py b/lib/spack/spack/schema/merged.py
index 9555f7b194..11db4f78df 100644
--- a/lib/spack/spack/schema/merged.py
+++ b/lib/spack/spack/schema/merged.py
@@ -10,6 +10,7 @@
 """
 from llnl.util.lang import union_dicts
 
+import spack.schema.bootstrap
 import spack.schema.cdash
 import spack.schema.compilers
 import spack.schema.config
@@ -23,6 +24,7 @@ import spack.schema.upstreams
 
 #: Properties for inclusion in other schemas
 properties = union_dicts(
+    spack.schema.bootstrap.properties,
     spack.schema.cdash.properties,
     spack.schema.compilers.properties,
     spack.schema.config.properties,
diff --git a/lib/spack/spack/store.py b/lib/spack/spack/store.py
index 4fcd96cdd8..a04ece2027 100644
--- a/lib/spack/spack/store.py
+++ b/lib/spack/spack/store.py
@@ -193,6 +193,7 @@ class Store(object):
 
 def _store():
     """Get the singleton store instance."""
+    import spack.bootstrap
     config_dict = spack.config.get('config')
     root, unpadded_root, projections = parse_install_tree(config_dict)
     hash_length = spack.config.get('config:install_hash_length')
@@ -201,7 +202,8 @@ def _store():
     # reserved by Spack to bootstrap its own dependencies, since this would
     # lead to bizarre behaviors (e.g. cleaning the bootstrap area would wipe
     # user installed software)
-    if spack.paths.user_bootstrap_store == root:
+    enable_bootstrap = spack.config.get('bootstrap:enable', True)
+    if enable_bootstrap and spack.bootstrap.store_path() == root:
         msg = ('please change the install tree root "{0}" in your '
                'configuration [path reserved for Spack internal use]')
         raise ValueError(msg.format(root))
diff --git a/lib/spack/spack/test/bootstrap.py b/lib/spack/spack/test/bootstrap.py
index 97687ddb4d..fccf67e569 100644
--- a/lib/spack/spack/test/bootstrap.py
+++ b/lib/spack/spack/test/bootstrap.py
@@ -6,6 +6,7 @@ import pytest
 
 import spack.bootstrap
 import spack.store
+import spack.util.path
 
 
 @pytest.mark.regression('22294')
@@ -22,5 +23,29 @@ def test_store_is_restored_correctly_after_bootstrap(mutable_config, tmpdir):
     # Test that within the context manager we use the bootstrap store
     # and that outside we restore the correct location
     with spack.bootstrap.ensure_bootstrap_configuration():
-        assert spack.store.root == spack.paths.user_bootstrap_store
+        assert spack.store.root == spack.bootstrap.store_path()
     assert spack.store.root == user_path
+
+
+@pytest.mark.parametrize('config_value,expected', [
+    # Absolute path without expansion
+    ('/opt/spack/bootstrap', '/opt/spack/bootstrap/store'),
+    # Path with placeholder
+    ('$spack/opt/bootstrap', '$spack/opt/bootstrap/store'),
+])
+def test_store_path_customization(config_value, expected, mutable_config):
+    # Set the current configuration to a specific value
+    spack.config.set('bootstrap:root', config_value)
+
+    # Check the store path
+    current = spack.bootstrap.store_path()
+    assert current == spack.util.path.canonicalize_path(expected)
+
+
+def test_raising_exception_if_bootstrap_disabled(mutable_config):
+    # Disable bootstrapping in config.yaml
+    spack.config.set('bootstrap:enable', False)
+
+    # Check the correct exception is raised
+    with pytest.raises(RuntimeError, match='bootstrapping is currently disabled'):
+        spack.bootstrap.store_path()
diff --git a/lib/spack/spack/test/cmd/bootstrap.py b/lib/spack/spack/test/cmd/bootstrap.py
new file mode 100644
index 0000000000..0537d85faa
--- /dev/null
+++ b/lib/spack/spack/test/cmd/bootstrap.py
@@ -0,0 +1,101 @@
+# Copyright 2013-2021 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+import os.path
+
+import pytest
+
+import spack.config
+import spack.environment
+import spack.main
+
+_bootstrap = spack.main.SpackCommand('bootstrap')
+
+
+@pytest.mark.parametrize('scope', [
+    None, 'site', 'system', 'user'
+])
+def test_enable_and_disable(mutable_config, scope):
+    scope_args = []
+    if scope:
+        scope_args = ['--scope={0}'.format(scope)]
+
+    _bootstrap('enable', *scope_args)
+    assert spack.config.get('bootstrap:enable', scope=scope) is True
+
+    _bootstrap('disable', *scope_args)
+    assert spack.config.get('bootstrap:enable', scope=scope) is False
+
+
+@pytest.mark.parametrize('scope', [
+    None, 'site', 'system', 'user'
+])
+def test_root_get_and_set(mutable_config, scope):
+    scope_args, path = [], '/scratch/spack/bootstrap'
+    if scope:
+        scope_args = ['--scope={0}'.format(scope)]
+
+    _bootstrap('root', path, *scope_args)
+    out = _bootstrap('root', *scope_args, output=str)
+    assert out.strip() == path
+
+
+@pytest.mark.parametrize('scopes', [
+    ('site',),
+    ('system', 'user')
+])
+def test_reset_in_file_scopes(mutable_config, scopes):
+    # Assert files are created in the right scopes
+    bootstrap_yaml_files = []
+    for s in scopes:
+        _bootstrap('disable', '--scope={0}'.format(s))
+        scope_path = spack.config.config.scopes[s].path
+        bootstrap_yaml = os.path.join(
+            scope_path, 'bootstrap.yaml'
+        )
+        assert os.path.exists(bootstrap_yaml)
+        bootstrap_yaml_files.append(bootstrap_yaml)
+
+    _bootstrap('reset', '-y')
+    for bootstrap_yaml in bootstrap_yaml_files:
+        assert not os.path.exists(bootstrap_yaml)
+
+
+def test_reset_in_environment(mutable_mock_env_path, mutable_config):
+    env = spack.main.SpackCommand('env')
+    env('create', 'bootstrap-test')
+    current_environment = spack.environment.read('bootstrap-test')
+
+    with current_environment:
+        _bootstrap('disable')
+        assert spack.config.get('bootstrap:enable') is False
+        _bootstrap('reset', '-y')
+        # We have no default settings in tests
+        assert spack.config.get('bootstrap:enable') is None
+
+    # Check that reset didn't delete the entire file
+    spack_yaml = os.path.join(current_environment.path, 'spack.yaml')
+    assert os.path.exists(spack_yaml)
+
+
+def test_reset_in_file_scopes_overwrites_backup_files(mutable_config):
+    # Create a bootstrap.yaml with some config
+    _bootstrap('disable', '--scope=site')
+    scope_path = spack.config.config.scopes['site'].path
+    bootstrap_yaml = os.path.join(scope_path, 'bootstrap.yaml')
+    assert os.path.exists(bootstrap_yaml)
+
+    # Reset the bootstrap configuration
+    _bootstrap('reset', '-y')
+    backup_file = bootstrap_yaml + '.bkp'
+    assert not os.path.exists(bootstrap_yaml)
+    assert os.path.exists(backup_file)
+
+    # Iterate another time
+    _bootstrap('disable', '--scope=site')
+    assert os.path.exists(bootstrap_yaml)
+    assert os.path.exists(backup_file)
+    _bootstrap('reset', '-y')
+    assert not os.path.exists(bootstrap_yaml)
+    assert os.path.exists(backup_file)
diff --git a/share/spack/spack-completion.bash b/share/spack/spack-completion.bash
index cd5a01c42d..44cc7945fd 100755
--- a/share/spack/spack-completion.bash
+++ b/share/spack/spack-completion.bash
@@ -333,7 +333,7 @@ _spack() {
     then
         SPACK_COMPREPLY="-h --help -H --all-help --color -c --config -C --config-scope -d --debug --timestamp --pdb -e --env -D --env-dir -E --no-env --use-env-repo -k --insecure -l --enable-locks -L --disable-locks -m --mock -p --profile --sorted-profile --lines -v --verbose --stacktrace -V --version --print-shell-vars"
     else
-        SPACK_COMPREPLY="activate add analyze arch audit blame build-env buildcache cd checksum ci clean clone commands compiler compilers concretize config containerize create deactivate debug dependencies dependents deprecate dev-build develop docs edit env extensions external fetch find flake8 gc gpg graph help info install license list load location log-parse maintainers mark mirror module monitor patch pkg providers pydoc python reindex remove rm repo resource restage solve spec stage style test test-env tutorial undevelop uninstall unit-test unload url verify versions view"
+        SPACK_COMPREPLY="activate add analyze arch audit blame bootstrap build-env buildcache cd checksum ci clean clone commands compiler compilers concretize config containerize create deactivate debug dependencies dependents deprecate dev-build develop docs edit env extensions external fetch find flake8 gc gpg graph help info install license list load location log-parse maintainers mark mirror module monitor patch pkg providers pydoc python reindex remove rm repo resource restage solve spec stage style test test-env tutorial undevelop uninstall unit-test unload url verify versions view"
     fi
 }
 
@@ -416,6 +416,36 @@ _spack_blame() {
     fi
 }
 
+_spack_bootstrap() {
+    if $list_options
+    then
+        SPACK_COMPREPLY="-h --help"
+    else
+        SPACK_COMPREPLY="enable disable reset root"
+    fi
+}
+
+_spack_bootstrap_enable() {
+    SPACK_COMPREPLY="-h --help --scope"
+}
+
+_spack_bootstrap_disable() {
+    SPACK_COMPREPLY="-h --help --scope"
+}
+
+_spack_bootstrap_reset() {
+    SPACK_COMPREPLY="-h --help -y --yes-to-all"
+}
+
+_spack_bootstrap_root() {
+    if $list_options
+    then
+        SPACK_COMPREPLY="-h --help --scope"
+    else
+        SPACK_COMPREPLY=""
+    fi
+}
+
 _spack_build_env() {
     if $list_options
     then