GCP Toolbox (i.e. scripts)

gcp_container_registry_cleanup.md

GCR Image Cleanup Script

A simple Bash script to clean up Google Container Registry (GCR) images older than a specified number of days. Includes a dry-run mode to preview deletions without making any changes.

Prerequisites

• Google Cloud SDK (gcloud) installed and authenticated.
• jq installed for JSON processing.
• Access to the GCR repository from Cloud Shell or your local environment.

Setup

1. Download the Script:

   Save the cleanup_gcr.sh script to your desired directory.

2. Make the Script Executable:

   chmod +x cleanup_gcr.sh

gcp_container_registry_cleanup.sh

#!/bin/bash

# Script to clean up Google Container Registry images older than a specified number of days.
# Supports a dry-run mode to simulate deletions without performing them.

# Exit immediately if a command exits with a non-zero status
set -e

# Variables
PROJECT_ID="your-gcp-project-id"        # Replace with your GCP Project ID
GCR_REPO="your-container-registry"      # Replace with your GCR repository name, e.g., "gcr.io/project-id"
OLDER_THAN_DAYS=30                      # Number of days to consider for deletion

# Default mode is actual deletion
DRY_RUN=false

# Function to display usage
usage() {
  echo "Usage: $0 [--dry-run]"
  echo ""
  echo "Options:"
  echo "  --dry-run    Simulate deletions without removing any images."
  echo "  -h, --help   Display this help message."
  exit 1
}

# Parse command-line arguments
while [[ "$#" -gt 0 ]]; do
    case $1 in
        --dry-run)
            DRY_RUN=true
            shift
            ;;
        -h|--help)
            usage
            ;;
        *)
            echo "Unknown parameter passed: $1"
            usage
            ;;
    esac
done

# Set the project
gcloud config set project "${PROJECT_ID}"

# Get the current date and calculate the cutoff date
CUTOFF_DATE=$(date -d "-${OLDER_THAN_DAYS} days" +%s)

# Fetch all images in the GCR repository
echo "Fetching images from ${GCR_REPO}..."
IMAGES=$(gcloud container images list --repository="${GCR_REPO}" --format="value(NAME)")

if [[ -z "$IMAGES" ]]; then
  echo "No images found in the repository: ${GCR_REPO}."
  exit 0
fi

# Iterate through each image and check tags
for IMAGE in $IMAGES; do
  echo "Processing image: $IMAGE"
  
  # Get all tags for the image in JSON format
  TAGS=$(gcloud container images list-tags "$IMAGE" --format="json")

  if [[ "$TAGS" == "[]" ]]; then
    echo "No tags found for $IMAGE. Skipping..."
    continue
  fi

  # Process each tag
  echo "$TAGS" | jq -c '.[]' | while read -r TAG; do
    # Extract timestamp, digest, and tag name
    TIMESTAMP=$(echo "$TAG" | jq -r '.timestamp.datetime')
    DIGEST=$(echo "$TAG" | jq -r '.digest')
    TAG_NAME=$(echo "$TAG" | jq -r '.tags[]?')

    # Convert timestamp to seconds since epoch
    TIMESTAMP_SECONDS=$(date -d "$TIMESTAMP" +%s)

    # Check if the image is older than the cutoff date
    if [[ $TIMESTAMP_SECONDS -lt $CUTOFF_DATE ]]; then
      if $DRY_RUN; then
        echo "[Dry-Run] Would delete: $IMAGE@$DIGEST (tag: $TAG_NAME, timestamp: $TIMESTAMP)"
      else
        echo "Deleting old image: $IMAGE@$DIGEST (tag: $TAG_NAME, timestamp: $TIMESTAMP)"
        # Delete the specific digest
        gcloud container images delete "${IMAGE}@${DIGEST}" --quiet --force-delete-tags
      fi
    else
      echo "Skipping recent image: $IMAGE@$DIGEST (tag: $TAG_NAME, timestamp: $TIMESTAMP)"
    fi
  done
done

if $DRY_RUN; then
  echo "Dry-run completed. No images were deleted."
else
  echo "Cleanup completed."
fi