circle-lock.sh

#!/usr/bin/env bash

set -o xtrace -o errexit -o pipefail -o nounset

########################################################################################
# CircleCI's current recommendation for roughly serializing a subset
# of build commands for a given branch
#
# circle discussion thread - https://discuss.circleci.com/t/serializing-deployments/153
# Code from - https://github.com/bellkev/circle-lock-test
########################################################################################


# sets $branch, $job_name, $tag, $rest
parse_args() {
    while [[ $# -gt 0 ]]; do
        case $1 in
            -b|--branch) branch="$2" ;;
            -j|--job-name) job_name="$2" ;;
            -t|--tag) tag="$2" ;;
            *) break ;;
        esac
        shift 2
    done
    rest=("$@")
}

# reads $branch, $tag, $commit_message
should_skip() {
    if [[ "$branch" && "$CIRCLE_BRANCH" != "$branch" ]]; then
        echo "Not on branch $branch. Skipping..."
        return 0
    fi

    if [[ "$job_name" && "$CIRCLE_JOB" != "$job_name" ]]; then
        echo "Not running $job_name. Skipping..."
        return 0
    fi

    if [[ "$tag" && "$commit_message" != *\[$tag\]* ]]; then
        echo "No [$tag] commit tag found. Skipping..."
        return 0
    fi

    return 1
}

# reads $branch, $job_name, $tag
# sets $jq_prog
make_jq_prog() {
    local jq_filters=""

    if [[ $branch ]]; then
        jq_filters+=" and .branch == \"$branch\""
    fi

    if [[ $job_name ]]; then
        jq_filters+=" and .workflows?.job_name? == \"$job_name\""
    fi

    if [[ $tag ]]; then
        jq_filters+=" and (.subject | contains(\"[$tag]\"))"
    fi

    jq_prog=".[] | select(.build_num < $CIRCLE_BUILD_NUM and (.status | test(\"running|pending|queued\")) $jq_filters) | .build_num"
    jq_later_builds_prog=".[] | select(.build_num > $CIRCLE_BUILD_NUM and (.status | test(\"running|pending|queued\")) $jq_filters) | .build_num"
}


if [[ "$0" != *bats* ]]; then
set -e
set -u
set -o pipefail

    branch=""
    tag=""
    job_name=""
    rest=()
    api_url="https://circleci.com/api/v1/project/$CIRCLE_PROJECT_USERNAME/$CIRCLE_PROJECT_REPONAME?circle-token=$CIRCLE_TOKEN&limit=100"
    if [[ $branch ]]; then
        api_url="https://circleci.com/api/v1/project/$CIRCLE_PROJECT_USERNAME/$CIRCLE_PROJECT_REPONAME/tree/$branch?circle-token=$CIRCLE_TOKEN&limit=100"
    fi

    parse_args "$@"
    commit_message=$(git log -1 --pretty=%B)
    if should_skip; then exit 0; fi
    make_jq_prog

    echo "Checking for running builds..."

    while true; do
        builds=$(curl -s -H "Accept: application/json" "$api_url" | jq "$jq_prog")
        later_builds=$(curl -s -H "Accept: application/json" "$api_url" | jq "$jq_later_builds_prog")
        if [[ $later_builds ]]; then
            echo "Later builds detected, bailing"
            echo "$later_builds"
            exit 0
        fi
        if [[ $builds ]]; then
            echo "Waiting on builds:"
            echo "$builds"
        else
            break
        fi
        echo "Retrying in 10 seconds..."
        sleep 10
    done

    echo "Acquired lock"

    if [[ "${#rest[@]}" -ne 0 ]]; then
        "${rest[@]}"
    fi
fi