Use buildkit for harness builds (#582)

Author: kierenevans

Diff for: Jenkinsfile

@@ -1,6 +1,8 @@
 pipeline {
     agent none
     environment {
+        COMPOSE_DOCKER_CLI_BUILD = 1
+        DOCKER_BUILDKIT = 1
         MY127WS_KEY = credentials('base-my127ws-key-20190523')
     }
     options {

Diff for: src/_base/application/overlay/Jenkinsfile.twig

@@ -1,6 +1,8 @@
 pipeline {
     agent { label "my127ws" }
     environment {
+        COMPOSE_DOCKER_CLI_BUILD = {{ @('jenkins.docker.buildkit.enabled') ? '1' : '0' }}
+        DOCKER_BUILDKIT = {{ @('jenkins.docker.buildkit.enabled') ? '1' : '0' }}
         MY127WS_KEY = credentials('{{ @('jenkins.credentials.my127ws_key') }}')
         MY127WS_ENV = "pipeline"
     }

Diff for: src/_base/harness/attributes/common.yml

@@ -23,10 +23,13 @@ attributes.default:
   mutagen: yes
 
   jenkins:
-    tests:
-      isolated: true
     credentials:
       my127ws_key: = @('workspace.name') ~ '-my127ws-key'
+    docker:
+      buildkit:
+        enabled: true
+    tests:
+      isolated: true
 
   pipeline:
     base:

Diff for: src/drupal8/application/overlay/Jenkinsfile.twig

@@ -1,6 +1,8 @@
 pipeline {
     agent { label "my127ws" }
     environment {
+        COMPOSE_DOCKER_CLI_BUILD = {{ @('jenkins.docker.buildkit.enabled') ? '1' : '0' }}
+        DOCKER_BUILDKIT = {{ @('jenkins.docker.buildkit.enabled') ? '1' : '0' }}
         MY127WS_KEY = credentials('{{ @('jenkins.credentials.my127ws_key') }}')
         MY127WS_ENV = "pipeline"
     }