spack list: latest version (JSON) (#11652)

List the latest version of each package in JSON encoding.
Preparation for consumption for a "spack badge" service.

4 files changed, 81 insertions, 1 deletions

diff --git a/lib/spack/spack/cmd/list.py b/lib/spack/spack/cmd/list.py
index 9fe2809097..570dcc7e27 100644
--- a/lib/spack/spack/cmd/list.py
+++ b/lib/spack/spack/cmd/list.py
@@ -13,6 +13,7 @@ import os
 import re
 import sys
 import math
+import json
 
 import llnl.util.tty as tty
 from llnl.util.tty.colify import colify
@@ -20,6 +21,7 @@ from llnl.util.tty.colify import colify
 import spack.dependency
 import spack.repo
 import spack.cmd.common.arguments as arguments
+from spack.version import VersionList
 
 description = "list and search available packages"
 section = "basic"
@@ -116,6 +118,46 @@ def rows_for_ncols(elts, ncols):
         yield row
 
 
+def get_dependencies(pkg):
+    all_deps = {}
+    for deptype in spack.dependency.all_deptypes:
+        deps = pkg.dependencies_of_type(deptype)
+        all_deps[deptype] = [d for d in deps]
+
+    return all_deps
+
+
+@formatter
+def version_json(pkg_names, out):
+    """Print all packages with their latest versions."""
+    pkgs = [spack.repo.get(name) for name in pkg_names]
+
+    out.write('[\n')
+
+    # output name and latest version for each package
+    pkg_latest = ",\n".join([
+        '  {{"name": "{0}",\n'
+        '   "latest_version": "{1}",\n'
+        '   "versions": {2},\n'
+        '   "homepage": "{3}",\n'
+        '   "file": "{4}",\n'
+        '   "maintainers": {5},\n'
+        '   "dependencies": {6}'
+        '}}'.format(
+            pkg.name,
+            VersionList(pkg.versions).preferred(),
+            json.dumps([str(v) for v in reversed(sorted(pkg.versions))]),
+            pkg.homepage,
+            github_url(pkg),
+            json.dumps(pkg.maintainers),
+            json.dumps(get_dependencies(pkg))
+        ) for pkg in pkgs
+    ])
+    out.write(pkg_latest)
+    # important: no trailing comma in JSON arrays
+    out.write('\n]\n')
+
+
 @formatter
 def html(pkg_names, out):
     """Print out information on all packages in Sphinx HTML.
diff --git a/lib/spack/spack/test/cmd/list.py b/lib/spack/spack/test/cmd/list.py
index 3cd8207ba2..6590b9ab2a 100644
--- a/lib/spack/spack/test/cmd/list.py
+++ b/lib/spack/spack/test/cmd/list.py
@@ -45,6 +45,15 @@ def test_list_format_name_only():
 
 
 @pytest.mark.maybeslow
+def test_list_format_version_json():
+    output = list('--format', 'version_json')
+    assert '  {"name": "cloverleaf3d",' in output
+    assert '  {"name": "hdf5",' in output
+    import json
+    json.loads(output)
+
+
+@pytest.mark.maybeslow
 def test_list_format_html():
     output = list('--format', 'html')
     assert '<div class="section" id="cloverleaf3d">' in output
diff --git a/lib/spack/spack/test/versions.py b/lib/spack/spack/test/versions.py
index 11da83df8c..b39da0c698 100644
--- a/lib/spack/spack/test/versions.py
+++ b/lib/spack/spack/test/versions.py
@@ -9,7 +9,7 @@ where it makes sense.
 """
 import pytest
 
-from spack.version import Version, ver
+from spack.version import Version, VersionList, ver
 
 
 def assert_ver_lt(a, b):
@@ -548,3 +548,15 @@ def test_get_item():
     # Raise TypeError on tuples
     with pytest.raises(TypeError):
         b.__getitem__(1, 2)
+
+
+def test_list_highest():
+    vl = VersionList(['master', '1.2.3', 'develop', '3.4.5', 'foobar'])
+    assert vl.highest() == Version('develop')
+    assert vl.lowest() == Version('foobar')
+    assert vl.highest_numeric() == Version('3.4.5')
+
+    vl2 = VersionList(['master', 'develop'])
+    assert vl2.highest_numeric() is None
+    assert vl2.preferred() == Version('develop')
+    assert vl2.lowest() == Version('master')
diff --git a/lib/spack/spack/version.py b/lib/spack/spack/version.py
index 0235ce0182..286943119f 100644
--- a/lib/spack/spack/version.py
+++ b/lib/spack/spack/version.py
@@ -643,6 +643,23 @@ class VersionList(object):
         else:
             return self[-1].highest()
 
+    def highest_numeric(self):
+        """Get the highest numeric version in the list."""
+        numeric_versions = list(filter(
+            lambda v: str(v) not in infinity_versions,
+            self.versions))
+        if not any(numeric_versions):
+            return None
+        else:
+            return numeric_versions[-1].highest()
+
+    def preferred(self):
+        """Get the preferred (latest) version in the list."""
+        latest = self.highest_numeric()
+        if latest is None:
+            latest = self.highest()
+        return latest
+
     @coerced
     def overlaps(self, other):
         if not other or not self: