tools/generate-changelog.py: add a permalink in the changelog from wh…

…ich the current build is sourced

Makefile

@@ -2,6 +2,7 @@
 TESTDIR ?= "prime/"
 SNAP_NAME=core24
 BUILDDIR=/build/$(SNAP_NAME)
+REPO_URL=https://github.com/canonical/core-base
 
 .PHONY: all
 all: check
@@ -48,12 +49,14 @@ install:
 
 	# generate the changelog, for this we need the previous core snap
 	# to be installed, this should be handled in snapcraft.yaml
+	commit="$$(git rev-parse HEAD)"
 	if [ -e "/snap/$(SNAP_NAME)/current/usr/share/snappy/dpkg.yaml" ]; then \
 		./tools/generate-changelog.py \
 			"/snap/$(SNAP_NAME)/current/usr/share/snappy/dpkg.yaml" \
 			"$(DESTDIR)/usr/share/snappy/dpkg.yaml" \
 			"$(DESTDIR)/usr/share/doc" \
 			$(DESTDIR)/usr/share/doc/ChangeLog; \
+			"$(REPO_URL)/tree/$(commit)"
 	else \
 		echo "WARNING: changelog will not be generated for this build"; \
 	fi

tools/generate-changelog.py

@@ -27,6 +27,7 @@
 import gzip
 import os
 import requests
+import subprocess
 import sys
 import yaml
 from collections import namedtuple
@@ -175,13 +176,17 @@ def main():
     parser.add_argument('new', metavar='new-manifest', help='Path to the manifest of the new snap')
     parser.add_argument('docs', metavar='docs-dir', help='Path to the usr/share/doc directory in the rootfs of the new snap')
     parser.add_argument('out', help='Optionally a path to where the changelog should be written')
+    parser.add_argument('permalink', help='Permalink to embed inside the changelog')
     args = parser.parse_args()
 
     old_manifest = args.old
     new_manifest = args.new
     docs_dir = args.docs
 
-    changes = '[ Changes in primed packages ]\n\n'
+    # add a header that helps us audit where the current build is
+    # sourced from.
+    changes = f"Built from commit {args.permalink}\n\n"
+    changes += '[ Changes in primed packages ]\n\n'
     pkg_changes = compare_manifests(old_manifest, new_manifest, docs_dir)
     if pkg_changes != '':
         changes += pkg_changes