Add PoC script that generates a changelog from GitLab MRs

refs #17886

bin/generate-changelog

+#! /usr/bin/python3
+
+import datetime
+import email.utils
+import functools
+import gitlab
+import jinja2
+import logging
+import os
+import pprint
+import re
+
+from pathlib import Path
+
+PYTHON_GITLAB_CONFIG_FILE = os.getenv('PYTHON_GITLAB_CONFIG_FILE',
+                                      default=Path.home() /
+                                      '.python-gitlab.cfg')
+
+PYTHON_GITLAB_NAME = os.getenv('GITLAB_NAME', default='Tails')
+
+GROUP_NAME = 'tails'
+
+# Only changes in these projects are considered
+PROJECTS = [
+    GROUP_NAME + '/' + project for project in [
+        'chutney',
+        'installer',
+        'tails',
+        'whisperback',
+        'workarounds',
+    ]
+]
+
+# Merge requests that modify only files whose path match one of IGNORED_PATHS
+# are ignored.
+# Patterns will be passed to re.fullmatch().
+IGNORED_PATHS = [
+    r'po/.*',
+    r'wiki/.*',
+]
+
+LOG_FORMAT = "%(asctime)-15s %(levelname)s %(message)s"
+log = logging.getLogger()
+
+
+class GitLabWrapper(gitlab.Gitlab):
+    @functools.lru_cache
+    def project(self, project_id):
+        return self.projects.get(project_id)
+
+    @functools.lru_cache
+    def project_path_with_namespace(self, project_id):
+        return self.project(project_id).path_with_namespace
+
+
+class ChangelogGenerator(object):
+    def __init__(self, gl, group, version: str):
+        self.gl = gl
+        self.group = group
+        self.version = version
+
+    def merge_requests(self, milestone) -> list:
+        mrs = []
+
+        gl_mrs = [
+            mr for mr in milestone.merge_requests(all=True, state='merged')
+            if self.gl.project_path_with_namespace(mr.target_project_id) in
+            PROJECTS
+        ]
+
+        for mr in gl_mrs:
+            project = self.gl.project(mr.target_project_id)
+            mr = project.mergerequests.get(mr.iid)
+            if ignore_merge_request(mr):
+                continue
+            # yapf: disable
+            mrs.append({
+                "ref": mr.references['full'],
+                "title": mr.title,
+                "web_url": mr.web_url,
+                "closes_issues": [
+                    {
+                        "ref": project.issues.get(issue.iid).references['full'],
+                        "title": issue.title,
+                    }
+                    for issue in mr.closes_issues()
+                ],
+                "commit_messages": [commit.title for commit in mr.commits()],
+            })
+            # yapf: enable
+
+        return mrs
+
+    def changes(self) -> dict:
+        milestone_title = "Tails_" + self.version
+        milestone = [
+            m for m in self.group.milestones.list(search=milestone_title)
+            # Disambiguate between milestones whose names share a common prefix
+            if m.title == milestone_title
+        ][0]
+        assert isinstance(milestone, gitlab.v4.objects.GroupMilestone)
+
+        return {
+            "merge_requests": self.merge_requests(milestone),
+            "issues": {},  # XXX: do we we really want this?
+        }
+
+
+def ignore_merge_request(mr) -> bool:
+    for change in mr.changes()['changes']:
+        for path in [change['old_path'], change['new_path']]:
+            if all([
+                    re.fullmatch(ignored_path, path) is None
+                    for ignored_path in IGNORED_PATHS
+            ]):
+                log.debug("Returning false")
+                return False
+    log.debug("Returning true")
+    return True
+
+
+def changelog_entry(version: str, date: datetime, changes: dict):
+    jinja2_env = jinja2.Environment(
+        loader=jinja2.FileSystemLoader('config/release_management/templates'),
+        trim_blocks=True,
+        lstrip_blocks=True,
+    )
+
+    return jinja2_env.get_template('changelog.jinja2').render(
+        merge_requests=changes['merge_requests'],
+        issues=changes['issues'],
+        date=email.utils.format_datetime(date),
+        version=version,
+    )
+
+
+if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--version', required=True)
+    parser.add_argument("--debug", action="store_true", help="debug output")
+    args = parser.parse_args()
+
+    if args.debug:
+        logging.basicConfig(level=logging.DEBUG, format=LOG_FORMAT)
+    else:
+        logging.basicConfig(level=logging.INFO, format=LOG_FORMAT)
+
+    gl = GitLabWrapper.from_config(PYTHON_GITLAB_NAME,
+                                   config_files=[PYTHON_GITLAB_CONFIG_FILE])
+    gl.auth()
+
+    group = gl.groups.list(search=GROUP_NAME)[0]
+    assert isinstance(group, gitlab.v4.objects.Group)
+
+    changes = ChangelogGenerator(gl, group, args.version).changes()
+
+    log.debug(pprint.PrettyPrinter().pformat(changes))
+
+    print(
+        changelog_entry(version=args.version,
+                        date=datetime.datetime.now(datetime.timezone.utc),
+                        changes=changes))

config/release_management/templates/changelog.jinja2

+{# Jinja2 template used by bin/generate-changelog -#}
+
+tails ({{version}}) unstable; urgency=medium
+
+{% for mr in merge_requests %}
+  {% set mr_desc = mr.title + " (" + mr.ref + ")" %}
+  * {{ mr_desc|wordwrap(wrapstring="\n    ")}}
+    {% if mr.closes_issues %}
+    Closes issues:
+      {% for issue in mr.closes_issues %}
+	{% set issue_desc = issue.title + " (" + issue.ref + ")" %}
+      - {{ issue_desc|wordwrap(wrapstring="\n        ") }}
+      {% endfor %}
+    {% endif %}
+    Commits:
+      {% for commit_message in mr.commit_messages %}
+      - {{ commit_message|wordwrap(wrapstring="\n        ") }}
+      {% endfor %}
+
+{% endfor %}
+ -- Tails developers <tails@boum.org>  {{date}}