[FAB-17166] Gate UT, IT and DocBuild

Adds a gate behind VerifyBuild that will tell
the other jobs which of them should run depending
on which directories in the source tree have
been updated

Signed-off-by: Brett Logan <Brett.T.Logan@ibm.com>

ci/azure-pipelines.yml

@@ -23,9 +23,13 @@ jobs:
         path: 'go/src/github.com/hyperledger/fabric'
         displayName: Checkout Fabric Code
       - script: make basic-checks native
-        displayName: Verify Build
+        displayName: Run Basic Checks
+      - script: ./ci/scripts/evaluate_commits.sh
+        name: SetJobTriggers
 
   - job: DocBuild
+    condition: eq(dependencies.VerifyBuild.outputs['SetJobTriggers.buildDoc'], 'true')
+    dependsOn: VerifyBuild
     pool:
       vmImage: ubuntu-18.04
     container:
@@ -40,6 +44,8 @@ jobs:
         displayName: Publish Documentation Artifacts
 
   - job: UnitTests
+    condition: eq(dependencies.VerifyBuild.outputs['SetJobTriggers.runTests'], 'true')
+    dependsOn: VerifyBuild
     pool:
       vmImage: ubuntu-18.04
     steps:
@@ -53,6 +59,8 @@ jobs:
         displayName: Run Unit Tests
 
   - job: IntegrationTests
+    condition: eq(dependencies.VerifyBuild.outputs['SetJobTriggers.runTests'], 'true')
+    dependsOn: VerifyBuild
     pool:
       vmImage: ubuntu-18.04
     strategy:

ci/scripts/evaluate_commits.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+# Copyright IBM Corp. All Rights Reserved.
+#
+# SPDX-License-Identifier: Apache-2.0
+set -euo pipefail
+
+if [[ $(git diff-tree --no-commit-id --name-only 'HEAD^..HEAD') == "docs" ]]; then
+  echo "##vso[task.setvariable variable=buildDoc;isOutput=true]true"
+else
+  echo "##vso[task.setvariable variable=buildDoc;isOutput=true]true"
+  echo "##vso[task.setvariable variable=runTests;isOutput=true]true"
+fi