distros-info: add option to print all active NM branches

Add option --all to distros_support.py to show all the NM versions that
are being actively used by any active distro. This will be useful to
decide what stable branches are we interested into actively backporting
fixes and which ones we're not.

.gitlab-ci/distros_support.py

@@ -44,11 +44,20 @@ def _nm_version_is_newer(nm_ver, nm_ver_from):
     return False
 
 
-if len(sys.argv) != 2:
-    print(f"Usage: {sys.argv[0]} <nm_version>")
+def _print_usage():
+    print("Usage: distros_support.py [-a|--all] | <nm_version>")
+    print(" -a|--all:   print NM versions still active in any distro")
+    print(" nm_version: print all info and config.yml file of the specified NM version")
+
+
+if len(sys.argv) == 2 and sys.argv[1] in ("-h", "--help", "help"):
+    _print_usage()
+    quit()
+elif len(sys.argv) > 2:
+    print("Error: wrong arguments.", file=sys.stderr)
+    _print_usage()
     quit(code=1)
 
-nm_version = sys.argv[1]
 today = datetime.date.today()
 with open(os.path.dirname(__file__) + "/distros-info.yml") as f:
     distros_info = yaml.load(f, Loader=yaml.BaseLoader)
@@ -67,6 +76,24 @@ for distro, versions in distros_info.items():
             file=sys.stderr,
         )
 
+# If --all is selected, print all active NM versions and return
+if len(sys.argv) < 2 or sys.argv[1] in ("-a", "--all"):
+    nm_versions = {}
+
+    for distro, versions in distros_info.items():
+        for info in versions:
+            if not _is_supported(info["support"], today):
+                continue
+            nm_versions.setdefault(info["nm"], []).append(f"{distro} {info['version']}")
+
+    for nm_ver, distros in sorted(nm_versions.items(), reverse=True):
+        print("- NM {}: {}".format(nm_ver, ", ".join(distros)))
+
+    quit()
+
+# Otherwise, print all the info related to the specified NM version
+nm_version = sys.argv[1]
+
 # Print distros that uses this nm_version
 print(f"# List of distros using NM {nm_version}")
 print("---")