CI(CircleCI): Halt building if a draft PR (#1214)

* Halt building if a draft PR

.circleci/config.yml

@@ -30,6 +30,8 @@ workflows:
           filters: *filters-allow-all
 
       - docker-build-server:
+          context: &build-context
+            - github-readonly-public-repos
           filters: &filters-build
             tags:
               only: /.*/
@@ -38,35 +40,41 @@ workflows:
             - get-version
 
       - docker-build-frontend:
+          context: *build-context
           filters: *filters-build
           requires:
             - get-version
 
       - docker-build-webhooks:
+          context: *build-context
           filters: *filters-build
           requires:
             - get-version
             - test-server
 
       - docker-build-file-imports:
+          context: *build-context
           filters: *filters-build
           requires:
             - get-version
             - test-server
 
       - docker-build-previews:
+          context: *build-context
           filters: *filters-build
           requires:
             - get-version
             - test-server
 
       - docker-build-test-container:
+          context: *build-context
           filters: *filters-build
           requires:
             - get-version
             - test-server
 
       - docker-build-monitor-container:
+          context: *build-context
           filters: *filters-build
           requires:
             - get-version
@@ -365,11 +373,16 @@ jobs:
       - checkout
       - attach_workspace:
           at: /tmp/ci/workspace
+      - run:
+          name: determine if draft PR
+          command: |
+            echo "export IS_DRAFT_PR=$(.circleci/is_draft.sh)" >> workspace/env-vars
       - run: cat workspace/env-vars >> $BASH_ENV
+      - run: echo "IS_DRAFT_PR=${IS_DRAFT_PR}"
       - run:
           name: 'Check if should proceed'
           command: |
-            [[ "${CIRCLE_BRANCH}" != "main" && -z "${CIRCLE_PULL_REQUEST}" ]] && echo "Should not build, stopping" && circleci-agent step halt && exit 1
+            [[ "${CIRCLE_BRANCH}" != "main" && ("${IS_DRAFT_PR}" == "TRUE" || -z "${CIRCLE_PULL_REQUEST}") ]] && echo "Should not build, stopping" && circleci-agent step halt && exit 1
             echo "proceeding"
       - setup_remote_docker:
           # a weird issue with yarn installing packages throwing EPERM errors

.circleci/is_draft.sh

@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+
+# acknowledgements: https://github.com/vitalinfo/circleci-cancel-draft
+
+set -euf -o pipefail
+
+if [[ -z "$CIRCLE_PULL_REQUEST" ]]; then
+  echo "FALSE"
+fi
+
+PR_NUMBER="${CIRCLE_PULL_REQUEST//[!0-9]/}"
+RESPONSE=$(curl --silent \
+  -H "Authorization: token ${GITHUB_TOKEN}" \
+  -H "Accept: application/vnd.github.v3+json" \
+ "https://api.github.com/repos/${CIRCLE_PROJECT_USERNAME}/${CIRCLE_PROJECT_REPONAME}/pulls/${PR_NUMBER}"
+)
+
+DRAFT=$(echo "${RESPONSE}" | jq ".draft")
+DRAFT_LABEL=$(echo "${RESPONSE}" | jq ".labels | map(select(.name | test(\"Draft\"))) | .[]")
+
+if [[ ${DRAFT} == 'true' || ${DRAFT_LABEL} ]]; then
+  echo "TRUE"
+else
+  echo "FALSE"
+fi
+
+exit 0