feat: add ubuntu version-specific image tags

Add version-specific tags (e.g., ubuntu-noble, ubuntu-24.04) when pushing
images to Docker Hub. This allows users to pin to a specific Ubuntu version
and avoid unexpected breakage when the base image changes.

New tags pushed per image:
- ubuntu-{codename} (e.g., ubuntu-noble)
- ubuntu-{codename}-{date} (e.g., ubuntu-noble-20250101)
- ubuntu-{version} (e.g., ubuntu-24.04)
- ubuntu-{version}-{date} (e.g., ubuntu-24.04-20250101)

Existing tags (ubuntu, ubuntu-{date}, latest) are unchanged.

Closes #282

Author: matifali

README.md

@@ -19,6 +19,20 @@ https://hub.docker.com/r/codercom/example-base. The tag is taken from the
 filename of the Dockerfile. For example, `base/ubuntu.Dockerfile` is
 under the `ubuntu` tag.
 
+### Available Tags
+
+Each image is published with the following tag variants:
+
+| Tag                        | Example                                       | Description                                        |
+| -------------------------- | --------------------------------------------- | -------------------------------------------------- |
+| `ubuntu`                   | `codercom/example-base:ubuntu`                | Latest Ubuntu version (rolling)                    |
+| `ubuntu-{codename}`        | `codercom/example-base:ubuntu-noble`          | Pinned to a specific Ubuntu release codename       |
+| `ubuntu-{version}`         | `codercom/example-base:ubuntu-24.04`          | Pinned to a specific Ubuntu release version        |
+| `ubuntu-{date}`            | `codercom/example-base:ubuntu-20250101`       | Snapshot from a specific build date                |
+| `ubuntu-{codename}-{date}` | `codercom/example-base:ubuntu-noble-20250101` | Version-pinned snapshot from a specific build date |
+| `ubuntu-{version}-{date}`  | `codercom/example-base:ubuntu-24.04-20250101` | Version-pinned snapshot from a specific build date |
+| `latest`                   | `codercom/example-base:latest`                | Alias for the latest build                         |
+
 > For backward compatibility, these images are also available with the `enterprise-` prefix
 > (e.g., `codercom/enterprise-base`), but the `example-` prefix is recommended for new deployments.
 

scripts/push_images.sh

@@ -88,6 +88,23 @@ if [ $QUIET = true ]; then
   )
 fi
 
+# Extract Ubuntu version information from a locally loaded Docker image.
+# Sets UBUNTU_VERSION_ID (e.g., "24.04") and UBUNTU_VERSION_CODENAME (e.g., "noble").
+# Returns 1 if the version information could not be extracted.
+function get_ubuntu_version() {
+  local image_ref="$1"
+  local os_release
+
+  os_release=$(docker run --rm --entrypoint cat "$image_ref" /etc/os-release 2>/dev/null) || return 1
+
+  UBUNTU_VERSION_ID=$(echo "$os_release" | grep "^VERSION_ID=" | cut -d'"' -f2)
+  UBUNTU_VERSION_CODENAME=$(echo "$os_release" | grep "^VERSION_CODENAME=" | cut -d'=' -f2)
+
+  if [ -z "${UBUNTU_VERSION_ID:-}" ] || [ -z "${UBUNTU_VERSION_CODENAME:-}" ]; then
+    return 1
+  fi
+}
+
 date_str=$(date --utc +%Y%m%d)
 for image in "${IMAGES[@]}"; do
   image_dir="$PROJECT_ROOT/images/$image"
@@ -106,14 +123,31 @@ for image in "${IMAGES[@]}"; do
   fi
 
   build_id=$(cat "build_${image}.json" | jq -r .\[\"depot.build\"\].buildID)
-  
+
   # Push example images (primary)
   run_trace $DRY_RUN depot push --project "gb3p8xrshk" --tag "$example_image_ref" "$build_id"
   run_trace $DRY_RUN depot push --project "gb3p8xrshk" --tag "$example_image_ref_date" "$build_id"
   run_trace $DRY_RUN depot push --project "gb3p8xrshk" --tag "codercom/example-${image}:latest" "$build_id"
-  
+
   # Push enterprise images (alias)
   run_trace $DRY_RUN depot push --project "gb3p8xrshk" --tag "$enterprise_image_ref" "$build_id"
   run_trace $DRY_RUN depot push --project "gb3p8xrshk" --tag "$enterprise_image_ref_date" "$build_id"
   run_trace $DRY_RUN depot push --project "gb3p8xrshk" --tag "codercom/enterprise-${image}:latest" "$build_id"
+
+  # Push Ubuntu version-specific tags (e.g., ubuntu-noble, ubuntu-24.04)
+  # These allow users to pin to a specific Ubuntu version and avoid
+  # unexpected breakage when the base image changes.
+  if get_ubuntu_version "$enterprise_image_ref"; then
+    for prefix in "example" "enterprise"; do
+      # Codename tags (e.g., codercom/example-base:ubuntu-noble)
+      run_trace $DRY_RUN depot push --project "gb3p8xrshk" --tag "codercom/${prefix}-${image}:${TAG}-${UBUNTU_VERSION_CODENAME}" "$build_id"
+      run_trace $DRY_RUN depot push --project "gb3p8xrshk" --tag "codercom/${prefix}-${image}:${TAG}-${UBUNTU_VERSION_CODENAME}-${date_str}" "$build_id"
+
+      # Version number tags (e.g., codercom/example-base:ubuntu-24.04)
+      run_trace $DRY_RUN depot push --project "gb3p8xrshk" --tag "codercom/${prefix}-${image}:${TAG}-${UBUNTU_VERSION_ID}" "$build_id"
+      run_trace $DRY_RUN depot push --project "gb3p8xrshk" --tag "codercom/${prefix}-${image}:${TAG}-${UBUNTU_VERSION_ID}-${date_str}" "$build_id"
+    done
+  else
+    echo "Could not detect Ubuntu version for '$enterprise_image_ref'; skipping version-specific tags" >&2
+  fi
 done