ci: Create Zulip server pre-installed docker image template.

These Docker images will be useful for testing the upgrade process
from previous Zulip major releases to master.

Fixes part of #18346.

tools/ci/Dockerfile.prod.template

@@ -0,0 +1,30 @@
+# To build these production upgrade test images, say a Debian Buster system
+# preinstalled with Zulip 3.4 (RELEASE=buster, VERSION=3.4):
+#   0. $ tools/ci/generate-dockerfiles # Defined in tools/ci/images.yml
+#   1. $ docker build tools/ci/images/$RELEASE-$VERSION/ --tag zulip/ci:$RELEASE-$VERSION
+#   2. $ docker push zulip/ci:$RELEASE-$VERSION
+
+FROM {base_image}
+
+# Remove already existing rabbitmq mnesia directory files
+RUN sudo rm -rf /var/lib/rabbitmq/mnesia/*
+
+# The bionic hack used in production suite
+RUN if [ -f /etc/os-release ]; then \
+    . /etc/os-release \
+    && os_codename=$VERSION_CODENAME \
+    && if [ "$os_codename" = "bionic" ]; then \
+      sudo sed -i '/^bind/s/bind.*/bind 0.0.0.0/' /etc/redis/redis.conf; \
+    fi; \
+  fi
+
+
+# Download the release tarball, start rabbitmq server and install the server
+RUN cd $(mktemp -d) \
+  && wget https://www.zulip.org/dist/releases/zulip-server-{version}.tar.gz \
+  && tar -xf zulip-server-{version}.tar.gz \
+  && sudo service rabbitmq-server start \
+  && sudo service rabbitmq-server status \
+  && sudo -s ./zulip-server-{version}/scripts/setup/install --self-signed-cert --hostname 127.0.0.1 --email circleci@example.com
+
+CMD ["/bin/sh"]

tools/ci/Dockerfile.template

@@ -21,9 +21,9 @@
 # then borrows from the CircleCI Dockerfile.
 
 # To rebuild from this file for a given release, say bionic:
-#   0. $ tools/ci/generate-dockerfiles
-#   1. $ docker build tools/ci/images/$RELEASE/ --tag zulip/ci:$RELEASE
-#   2. $ docker push zulip/ci:$RELEASE
+#   1. $ tools/ci/generate-dockerfiles
+#   2. $ docker build tools/ci/images/$RELEASE/ --tag zulip/ci:$RELEASE
+#   3. $ docker push zulip/ci:$RELEASE
 
 FROM {base_image}
 

tools/ci/generate-dockerfiles

@@ -10,10 +10,13 @@ if __name__ == "__main__":
     with open("Dockerfile.template") as f:
         docker_template = f.read()
 
+    with open("Dockerfile.prod.template") as p:
+        docker_prod_template = p.read()
+
     with open("images.yml") as f:
         dockerfile_settings = yaml.safe_load(f)
 
-    for distro in dockerfile_settings:
+    for distro in dockerfile_settings["distros"]:
         dockerfile_path = f"images/{distro}/Dockerfile"
         os.makedirs(os.path.dirname(dockerfile_path), exist_ok=True)
         with open(dockerfile_path, "w") as f:
@@ -24,4 +27,17 @@ if __name__ == "__main__":
 
 """
             )
-            f.write(docker_template.format_map(dockerfile_settings[distro]))
+            f.write(docker_template.format_map(dockerfile_settings["distros"][distro]))
+
+    for server in dockerfile_settings["servers"]:
+        dockerfile_path = f"images/{server}/Dockerfile"
+        os.makedirs(os.path.dirname(dockerfile_path), exist_ok=True)
+        with open(dockerfile_path, "w") as f:
+            f.write(
+                """\
+# THIS IS A GENERATED FILE. DO NOT EDIT.
+# See template: tools/ci/Dockerfile.prod.template
+
+"""
+            )
+            f.write(docker_prod_template.format_map(dockerfile_settings["servers"][server]))

tools/ci/images.yml

@@ -1,11 +1,16 @@
-bionic:
+distros:
+  bionic:
     base_image: buildpack-deps:bionic-scm
 
-focal:
+  focal:
     base_image: buildpack-deps:focal-scm
 
-buster:
+  buster:
     base_image: buildpack-deps:buster-scm
 
-bullseye:
+  bullseye:
     base_image: buildpack-deps:bullseye-scm
+servers:
+  buster-3.4:
+    base_image: zulip/ci:buster
+    version: 3.4