Created
January 29, 2020 11:26
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Checks if a given docker image exists.
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| #!/bin/sh | |
| # | |
| # Checks if a given docker image exists. | |
| # | |
| # Usage: ./docker-image-exists.sh image[:tag] | |
| # | |
| # Requires curl and jq to be installed. | |
| # | |
| # Copyright 2016, Sebastian Tschan | |
| # https://blueimp.net | |
| # | |
| # Licensed under the MIT license: | |
| # https://opensource.org/licenses/MIT | |
| # | |
| # Exit immediately if a command exits with a non-zero status: | |
| set -e | |
| if [ -z "$1" ]; then | |
| echo 'Usage: ./docker-image-exists.sh image[:tag]' >&2 | |
| exit 1 | |
| fi | |
| # Parse aguments: | |
| IMAGE="${1%:*}" | |
| TAG="${1##*:}" | |
| if [ "$IMAGE" = "$TAG" ]; then | |
| TAG=latest | |
| fi | |
| # Retrieve Docker Basic Authentication token: | |
| CREDS_STORE="$(jq -r '.credsStore' "$HOME/.docker/config.json")" | |
| if [ "$CREDS_STORE" = null ]; then | |
| BASIC_AUTH="$(jq -r '.auths["https://index.docker.io/v1/"].auth' \ | |
| "$HOME/.docker/config.json")" | |
| else | |
| BASIC_AUTH=$(echo https://index.docker.io/v1/ | | |
| docker-credential-"$CREDS_STORE" get | | |
| jq -j '"\(.Username):\(.Secret)"' | | |
| base64) | |
| fi | |
| # Define Docker access scope: | |
| SCOPE="repository:$IMAGE:pull" | |
| # Define the Docker token and registry URLs: | |
| TOKEN_URL="https://auth.docker.io/token?service=registry.docker.io&scope=$SCOPE" | |
| REGISTRY_URL="https://registry-1.docker.io/v2/$IMAGE/manifests/$TAG" | |
| # Retrieve the access token: | |
| TOKEN="$(curl -sSL -H "Authorization: Basic $BASIC_AUTH" "$TOKEN_URL" | | |
| jq -r '.token')" | |
| # Check if the given image tag exists: | |
| curl -fsSLI -o /dev/null -H "Authorization: Bearer $TOKEN" "$REGISTRY_URL" |
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