MDBF-1239: Create and save the Galera source archive

We need at least one source of truth for storing and archiving the galera sources.
One is GitHub Releases but it doesn't resolve submodules, see: https://github.com/orgs/community/discussions/31795

Better let Buildbot handle the source archive generation
and release scripts will pick it up from ci.mariadb.org

Author: RazvanLiviuVarzaru

master-galera/master.cfg

@@ -94,6 +94,9 @@ if os.environ["ENVIRON"] == "DEV":
 # worker name and password must be configured on the worker.
 c["workers"] = []
 
+# Docker workers
+GALERA_PACKAGES = os.environ["GALERA_PACKAGES_DIR"]
+
 c["workers"].append(
     worker.DockerLatentWorker(
         "hz-bbw1-docker-galera-trigger",
@@ -107,6 +110,7 @@ c["workers"].append(
         hostconfig={"shm_size": "1G"},
         max_builds=1,
         build_wait_timeout=0,
+        volumes=[GALERA_PACKAGES + "/:/packages"],
     )
 )
 
@@ -123,12 +127,10 @@ c["workers"].append(
         hostconfig={"shm_size": "1G"},
         max_builds=1,
         build_wait_timeout=0,
+        volumes=[GALERA_PACKAGES + "/:/packages"],
     )
 )
 
-# Docker workers
-GALERA_PACKAGES = os.environ["GALERA_PACKAGES_DIR"]
-
 workers = defaultdict(list)
 
 
@@ -241,6 +243,13 @@ def dpkgDeb():
     )
 
 
+def isPushToSavedBranch(step):
+    return step.getProperty("event") == "push" and any(
+        fnmatch.fnmatch(step.getProperty("branch"), pattern)
+        for pattern in SAVED_PACKAGE_BRANCHES_GALERA
+    )
+
+
 def rpmSave():
     return steps.ShellCommand(
         name="move rpm files",
@@ -273,6 +282,51 @@ f_trigger_builds.addStep(
         doStepIf=waitIfStaging,
     )
 )
+f_trigger_builds.addStep(
+    steps.GitHub(
+        repourl=util.Property("repository"),
+        mode="full",
+        method="clobber",
+        workdir="build",
+        submodules=True,
+    )
+)
+f_trigger_builds.addStep(
+    steps.ShellCommand(
+        name="build source archive",
+        haltOnFailure=True,
+        workdir="build",
+        command=[
+            "bash",
+            "-xc",
+            """set -e
+./scripts/build.sh -a
+galera_version=$(basename galera-*.tar.gz .tar.gz)
+dest=$PWD/$galera_version
+# build.sh's gen_source_archive uses `git checkout-index`, which is
+# submodule-unaware and leaves submodule dirs empty (the same gap GitHub
+# Releases tarballs have). Copy each submodule's checked-out content in
+# before repacking, so the archive is actually self-contained.
+git submodule foreach 'cp -rvi * "'"$dest"'/${path}/"'
+tar czf ${galera_version}.tar.gz ${galera_version}/
+""",
+        ],
+    )
+)
+f_trigger_builds.addStep(
+    steps.ShellCommand(
+        name="save_source_archive",
+        timeout=7200,
+        haltOnFailure=True,
+        command=util.Interpolate(
+            """set -e
+mkdir -p /packages/%(prop:branch)s/%(prop:revision)s
+cp -v galera-*.tar.gz /packages/%(prop:branch)s/%(prop:revision)s/
+"""
+        ),
+        doStepIf=(lambda step: isPushToSavedBranch(step)),
+    )
+)
 
 ## f_deb_build - create source tarball
 f_deb_build = util.BuildFactory()