gitlab: add a CI job to validate the DCO sign off

While checkpatch.pl can validate DCO sign off that job must always be
advisory only since it is expected that certain patches will fail some
code style rules.

We require the DCO sign off to be mandatory for all commits though, so
it benefits from being validated in a standalone job.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20200918132903.1848939-3-berrange@redhat.com>
[thuth: Use "stage: build" to let it run earlier]
Signed-off-by: Thomas Huth <thuth@redhat.com>

.gitlab-ci.d/check-dco.py

@@ -0,0 +1,94 @@
+#!/usr/bin/env python3
+#
+# check-dco.py: validate all commits are signed off
+#
+# Copyright (C) 2020 Red Hat, Inc.
+#
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+import os
+import os.path
+import sys
+import subprocess
+
+namespace = "qemu-project"
+if len(sys.argv) >= 2:
+    namespace = sys.argv[1]
+
+cwd = os.getcwd()
+reponame = os.path.basename(cwd)
+repourl = "https://gitlab.com/%s/%s.git" % (namespace, reponame)
+
+subprocess.check_call(["git", "remote", "add", "check-dco", repourl])
+subprocess.check_call(["git", "fetch", "check-dco", "master"],
+                      stdout=subprocess.DEVNULL,
+                      stderr=subprocess.DEVNULL)
+
+ancestor = subprocess.check_output(["git", "merge-base",
+                                    "check-dco/master", "HEAD"],
+                                   universal_newlines=True)
+
+ancestor = ancestor.strip()
+
+subprocess.check_call(["git", "remote", "rm", "check-dco"])
+
+errors = False
+
+print("\nChecking for 'Signed-off-by: NAME <EMAIL>' " +
+      "on all commits since %s...\n" % ancestor)
+
+log = subprocess.check_output(["git", "log", "--format=%H %s",
+                               ancestor + "..."],
+                              universal_newlines=True)
+
+if log == "":
+    commits = []
+else:
+    commits = [[c[0:40], c[41:]] for c in log.strip().split("\n")]
+
+for sha, subject in commits:
+
+    msg = subprocess.check_output(["git", "show", "-s", sha],
+                                  universal_newlines=True)
+    lines = msg.strip().split("\n")
+
+    print("🔍 %s %s" % (sha, subject))
+    sob = False
+    for line in lines:
+        if "Signed-off-by:" in line:
+            sob = True
+            if "localhost" in line:
+                print("    ❌ FAIL: bad email in %s" % line)
+                errors = True
+
+    if not sob:
+        print("    ❌ FAIL missing Signed-off-by tag")
+        errors = True
+
+if errors:
+    print("""
+
+❌ ERROR: One or more commits are missing a valid Signed-off-By tag.
+
+
+This project requires all contributors to assert that their contributions
+are provided in compliance with the terms of the Developer's Certificate
+of Origin 1.1 (DCO):
+
+  https://developercertificate.org/
+
+To indicate acceptance of the DCO every commit must have a tag
+
+  Signed-off-by: REAL NAME <EMAIL>
+
+This can be achieved by passing the "-s" flag to the "git commit" command.
+
+To bulk update all commits on current branch "git rebase" can be used:
+
+  git rebase -i master -x 'git commit --amend --no-edit -s'
+
+""")
+
+    sys.exit(1)
+
+sys.exit(0)

.gitlab-ci.yml

@@ -411,3 +411,13 @@ check-patch:
   variables:
     GIT_DEPTH: 1000
   allow_failure: true
+
+check-dco:
+  stage: build
+  image: $CI_REGISTRY_IMAGE/qemu/centos8:latest
+  script: .gitlab-ci.d/check-dco.py
+  except:
+    variables:
+      - $CI_PROJECT_NAMESPACE == 'qemu-project' && $CI_COMMIT_BRANCH == 'master'
+  variables:
+    GIT_DEPTH: 1000