Cirrus: Print images that should be pruned

Over time unless they're removed, the project could grow quite a large
collection of VM images.  While generally cheap (less than a penny each,
per month), these will become a significant cost item if not kept
in-check.

Add a specialized container for handling image-pruning, but limit
it to only finding and printing (not actually deleting) images.

Also update the image-building workflow so that base-images used to
compose cache-images are also labeled with metadata.

N/B: As an additional safeguard, the service account which
     executes the new container in production *DOES NOT*
     have access to delete images.  This can be enabled
     by adding the GCE IAM role: CustomComputeImagePrune

Signed-off-by: Chris Evich <cevich@redhat.com>

1 files changed, 38 insertions, 1 deletions

diff --git a/contrib/cirrus/build_vm_images.sh b/contrib/cirrus/build_vm_images.sh
index f5d53a92e..74b10158c 100755
--- a/contrib/cirrus/build_vm_images.sh
+++ b/contrib/cirrus/build_vm_images.sh
@@ -3,7 +3,8 @@
 set -e
 source $(dirname $0)/lib.sh
 
-ENV_VARS='PACKER_BUILDS BUILT_IMAGE_SUFFIX UBUNTU_BASE_IMAGE FEDORA_BASE_IMAGE PRIOR_FEDORA_BASE_IMAGE SERVICE_ACCOUNT GCE_SSH_USERNAME GCP_PROJECT_ID PACKER_VER SCRIPT_BASE PACKER_BASE'
+BASE_IMAGE_VARS='FEDORA_BASE_IMAGE PRIOR_FEDORA_BASE_IMAGE UBUNTU_BASE_IMAGE'
+ENV_VARS="PACKER_BUILDS BUILT_IMAGE_SUFFIX $BASE_IMAGE_VARS SERVICE_ACCOUNT GCE_SSH_USERNAME GCP_PROJECT_ID PACKER_VER SCRIPT_BASE PACKER_BASE CIRRUS_BUILD_ID CIRRUS_CHANGE_IN_REPO"
 req_env_var $ENV_VARS
 # Must also be made available through make, into packer process
 export $ENV_VARS
@@ -24,6 +25,20 @@ then
 fi
 
 cd "$GOSRC/$PACKER_BASE"
+# Add/update labels on base-images used in this build to prevent premature deletion
+ARGS="
+"
+for base_image_var in $BASE_IMAGE_VARS
+do
+    # See entrypoint.sh in contrib/imgts and contrib/imgprune
+    # These updates can take a while, run them in the background, check later
+    gcloud compute images update "$image" \
+        --update-labels=last-used=$(date +%s) \
+        --update-labels=build-id=$CIRRUS_BUILD_ID \
+        --update-labels=repo-ref=$CIRRUS_CHANGE_IN_REPO \
+        --update-labels=project=$GCP_PROJECT_ID \
+        ${!base_image_var} &
+done
 
 make libpod_images \
     PACKER_BUILDS=$PACKER_BUILDS \
@@ -33,9 +48,31 @@ make libpod_images \
     PACKER_BASE=$PACKER_BASE \
     BUILT_IMAGE_SUFFIX=$BUILT_IMAGE_SUFFIX
 
+# Separate PR-produced images from those produced on master.
+if [[ "${CIRRUS_BRANCH:-}" == "master" ]]
+then
+    POST_MERGE_BUCKET_SUFFIX="-master"
+else
+    POST_MERGE_BUCKET_SUFFIX=""
+fi
+
 # When successful, upload manifest of produced images using a filename unique
 # to this build.
 URI="gs://packer-import${POST_MERGE_BUCKET_SUFFIX}/manifest${BUILT_IMAGE_SUFFIX}.json"
 gsutil cp packer-manifest.json "$URI"
 
+# Ensure any background 'gcloud compute images update' processes finish
+set +e  # need 'wait' exit code to avoid race
+while [[ -n "$(jobs)" ]]
+do
+    wait -n
+    RET=$?
+    if [[ "$RET" -eq "127" ]] || \   # Avoid TOCTOU race w/ jobs + wait
+       [[ "$RET" -eq "0" ]]
+    then
+        continue
+    fi
+    die $RET "Required base-image metadata update failed"
+done
+
 echo "Finished. A JSON manifest of produced images is available at $URI"