fetch_tags.sh

#!/bin/bash

###
# EXIT CODES
# 0 - success
# 1 - parameter error
# 50 - dockerhub pull error
# 51 - no valid docker image tag
# 52 - no old tag file found
# 53 - max tag count iteration reached
# 100 - new tag found, pr_script triggered
###

# Sample envionment variables
# IMAGE_ID="weaver-worker"
# DOCKERHUB_REPO="pavics/weaver"
# TAG_FILTER="^[0-9]+(\\.[0-9]+)*$"
# BUMP_TAG="s/(.*pavics\/canarieapi:).*/\\1NEW_TAG_VALUE/"
# BUMP_FILE="birdhouse/default.env"
# RAW_REPO="https://raw.githubusercontent.com/Ouranosinc/birdhouse-deploy-for-testing/master"

REQUIRED_ENV_VARS='
    IMAGE_ID
    DOCKERHUB_REPO
    TAG_FILTER
    BUMP_TAG
    BUMP_FILE
    RAW_REPO
'

# args parsing
for env_var in $REQUIRED_ENV_VARS
do
    if [[ ! -v "${env_var}" ]]; then
        echo "[ERROR] [$0] Missing ${env_var} environment variable. Exiting."
        exit 1
    fi
done

BLUE='\033[0;36m'
NC='\033[0m'

echo "[STEP] [$0] [$IMAGE_ID] Fetch tags"

# get latest image tag from dockerhub
mkdir -p $DATA_DIR
NAME=${DOCKERHUB_REPO//\//_}_$IMAGE_ID
NEW_FILENAME=$NAME.new
NEW_FILEPATH=$DATA_DIR/$NEW_FILENAME
DOCKERHUB_IMAGE_TAGS=$(wget -t 3 --timeout=3000 -q $DOCKERHUB_IMAGE_TAGS_URL$DOCKERHUB_REPO/tags?page_size=1024 -O-)

if [ "$DOCKERHUB_IMAGE_TAGS" == "" ]; then
    echo "[INFO] [$0] [$IMAGE_ID] DockerHub fetch timeout reached. Exiting."
    exit 50
fi

MAX_TAG_ITERATION=$(echo $DOCKERHUB_IMAGE_TAGS | jq -r '.results' | jq length)

if [ "$MAX_TAG_ITERATION" == "null" ]; then
    echo "[INFO] [$0] [$IMAGE_ID] DockerHub fetched null results. Exiting."
    exit 51
fi

TAG_INDEX=0
TAG_FILTER=${TAG_FILTER//\\\\/\\}    # replace \\ with \ in regex

while [[ ! $LATEST_TAG =~ $TAG_FILTER ]]
do
    # assumption that results are always in the same order, most recent first
    LATEST_TAG=$(echo $DOCKERHUB_IMAGE_TAGS | jq '.results['$TAG_INDEX'].name' | tr -d \")
    TAG_INDEX=$(($TAG_INDEX+1))

    if [[ $TAG_INDEX -gt $MAX_TAG_ITERATION ]]; then
        echo "[INFO] [$0] Reached max tag iteration count. Exiting."
        exit 53
    fi
done

if [ "$LATEST_TAG" == "" ]; then
    echo "[INFO] [$0] [$IMAGE_ID] No valid tag found. Exiting."
    exit 51
fi

echo $LATEST_TAG > $NEW_FILEPATH


# make sure data is persisted to file
if [ ! -f "$NEW_FILEPATH" ]; then
    echo "[WARNING] [$0] [$IMAGE_ID] Error when pulling DockerHub data. Exiting."
    exit 50
fi


# diff with old file
OLD_FILENAME=$NAME.old
OLD_FILEPATH=$DATA_DIR/$OLD_FILENAME

NEW_TAG_FOUND=false

# default tag values, sync with real repo values, if .old file does not exists
if [ ! -f "$OLD_FILEPATH" ]; then
    CURRENT_BUMP_FILE_CONTENT=$(curl --silent $RAW_REPO/$BUMP_FILE)
    TRIMMED_TAG_FILTER=${TAG_FILTER:1:-1}    # remove first and last string chars (^ and $). TODO: cleaner way to do this
    CURRENT_DEFAULT_TAG=$(echo "$CURRENT_BUMP_FILE_CONTENT" | grep "$DOCKERHUB_REPO" | grep -oE "$TRIMMED_TAG_FILTER" | tail -1)

    echo "[INFO] [$0] [$IMAGE_ID] No old file found to compare with. Took [$CURRENT_DEFAULT_TAG]"
    echo $CURRENT_DEFAULT_TAG > $OLD_FILEPATH
fi

if [ -f "$OLD_FILEPATH" ] && [ -f "$NEW_FILEPATH" ]; then
    if diff $OLD_FILEPATH $NEW_FILEPATH &> /dev/null; then
        echo "[INFO] [$0] [$IMAGE_ID] No new tag found. Exiting."
        rm $NEW_FILEPATH
        exit 0
    else
        NEW_TAG_FOUND=true
        OLD_TAG=$(cat $OLD_FILEPATH)

        printf "${BLUE}"
        echo "[INFO] [$0] [$IMAGE_ID] Found new tag: $LATEST_TAG, old tag was $OLD_TAG"
        printf "${NC}"

        # dry run
        if [[ $DRY_RUN == 1 ]]; then
            exit 0
        fi
    fi
else
    echo "[INFO] [$0] [$IMAGE_ID] No old file found to compare with. Skipping diff."
fi


# rotate historical files
mv $NEW_FILEPATH $OLD_FILEPATH

# useful for first time use
if [[ ! -z "${ONLY_UPDATE_TAGS_HISTORY}" ]]; then
    echo "[INFO] Tag for [$IMAGE_ID] updated and ONLY_UPDATE_TAGS_HISTORY used. Exiting."
    exit 0
fi

# launch pr_script with params
if [[ $NEW_TAG_FOUND = true ]]; then
    DOCKERHUB_REPO=$DOCKERHUB_REPO IMAGE_ID=$IMAGE_ID BUMP_TAG=$BUMP_TAG NEW_TAG_VALUE=$LATEST_TAG BUMP_FILE=$BUMP_FILE ./pr_script.sh
    
    # output to logs
    echo ${IMAGE_ID}:${LATEST_TAG} > $DATA_DIR/last-update-result.log    
    
    if [[ -z "${EXIT_BEFORE_PR}" ]]; then
        echo "[INFO] Created PR for [${IMAGE_ID}]. Exiting."
    fi

    exit 100
fi