From 21c75763345876c0909a300d3a5832bde1cede8d Mon Sep 17 00:00:00 2001
From: MarkKoz <KozlovMark@gmail.com>
Date: Sun, 12 May 2019 15:19:12 -0700
Subject: Retrieve previous build's commit using a REST API

The "Builds - List" endpoint is used to retrieve only the most recent
successful build. Builds will be fetched for the target branch if the
current build is for a PR. Otherwise, the current build's source branch
is used.

* Remove variable group and COMMIT_HASH stuff
* Add logging to the "Check Changed Files" step
---
 azure-pipelines.yml | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index b5a6860..883f554 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -33,9 +33,6 @@ jobs:
   displayName: 'Build'
   dependsOn: test
 
-  variables:
-    - group: snekbox
-
   steps:
   - task: Docker@1
     displayName: 'Login: Docker Hub'
@@ -46,11 +43,19 @@ jobs:
       command: 'login'
 
   - script: |
-      if [[ -z $COMMIT_HASH ]] || [[ -n "$(git diff $COMMIT_HASH -- docker/base.Dockerfile)" ]]; then
+      REQUEST_URL="https://dev.azure.com/python-discord/${SYSTEM_TEAMPROJECTID}/_apis/build/builds?queryOrder=finishTimeDescending&resultFilter=succeeded&\$top=1&repositoryType=${BUILD_REPOSITORY_PROVIDER}&repositoryId=${BUILD_REPOSITORY_NAME}&branchName=${SYSTEM_PULLREQUEST_TARGETBRANCH:-BUILD_SOURCEBRANCH}&api-version=5.0"
+      echo "Retrieving previous build's commit using $REQUEST_URL"
+
+      PREV_COMMIT="$(curl -sSL "${REQUEST_URL}" | grep -Po '"sourceVersion":"\K.*?[^\\](?=",)')"
+      echo "Retrieved $PREV_COMMIT as previous build's commit."
+
+      if [[ -z $PREV_COMMIT ]] || [[ -n "$(git diff $PREV_COMMIT -- docker/base.Dockerfile)" ]]; then
+        echo "Detected changes in docker/base.Dockerfile"
         echo "##vso[task.setvariable variable=BASE_CHANGED]1"
       fi
 
-      if [[ -z $COMMIT_HASH ]] || [[ -n "$(git diff $COMMIT_HASH -- Pipfile* docker/venv.Dockerfile)" ]]; then
+      if [[ -z $PREV_COMMIT ]] || [[ -n "$(git diff $PREV_COMMIT -- Pipfile* docker/venv.Dockerfile)" ]]; then
+        echo "Detected changes in Pipfile, Pipfile.lock, and/or docker/venv.Dockerfile"
         echo "##vso[task.setvariable variable=VENV_CHANGED]1"
       fi
     displayName: 'Check Changed Files'
@@ -74,8 +79,5 @@ jobs:
     displayName: 'Push Virtual Environment Image to Dockerhub'
     condition: and(succeeded(), or(variables.BASE_CHANGED, variables.VENV_CHANGED))
 
-  - script: echo "##vso[task.setvariable variable=COMMIT_HASH]$Build.SourceVersion"
-    displayName: 'Update Saved Commit Hash'
-
   - script: echo "Final image push simulation"
     displayName: 'Push Final Image to Dockerhub'
-- 
cgit v1.2.3