From 360cfeed5e6b7b7389a3d0e4ae6438401191b29c Mon Sep 17 00:00:00 2001
From: pat-s <pat-s@noreply.gitea.io>
Date: Thu, 2 Mar 2023 14:24:51 +0800
Subject: [PATCH] Add PR preview (#237)

Following the example repo at https://gitea.com/gitea/website-pr-preview, this PR will allow for automatically generated PR previews.

Required drone secrets:

- [ ] `GITEA_ACCESS_TOKEN`
- [ ] `AWS_ACCESS_KEY_ID`
- [ ] `AWS_SECRET_ACCESS_KEY`

I've also adjusted the old pipeline to only run for pushes to the default branch to avoid unneeded runs.

Co-authored-by: pat-s <patrick.schratz@gmail.com>
Reviewed-on: https://gitea.com/gitea/blog/pulls/237
Co-authored-by: pat-s <pat-s@noreply.gitea.io>
Co-committed-by: pat-s <pat-s@noreply.gitea.io>
---
 .drone.yml | 99 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 97 insertions(+), 2 deletions(-)

diff --git a/.drone.yml b/.drone.yml
index d667753..50d785e 100644
--- a/.drone.yml
+++ b/.drone.yml
@@ -1,6 +1,7 @@
 ---
 kind: pipeline
-name: default
+type: docker
+name: Build and deploy live website
 
 platform:
   os: linux
@@ -49,4 +50,98 @@ steps:
 
 trigger:
   branch:
-  - main
\ No newline at end of file
+    - main
+  event:
+    exclude:
+      - pull_request
+
+---
+kind: pipeline
+type: docker
+name: Build and deploy PR preview
+
+platform:
+  os: linux
+  arch: arm64
+
+trigger:
+  event:
+    - pull_request
+
+steps:
+  - name: build website
+    pull: always
+    image: golang:1.19
+    commands:
+      - make clean
+      - make build
+
+  - name: "[PR] create s3 bucket"
+    when:
+      event:
+        - pull_request
+    pull: always
+    image: alpine:latest
+    environment:
+      AWS_ACCESS_KEY_ID:
+        from_secret: preview_aws_access_token
+      AWS_SECRET_ACCESS_KEY:
+        from_secret: preview_aws_secret_access_key
+      AWS_REGION: eu-central-1
+    commands:
+      - apk add --no-cache aws-cli
+      - aws s3api create-bucket --acl public-read --bucket preview-gitea-org-blog-${DRONE_REPO_NAME}-${DRONE_PULL_REQUEST} --region $${AWS_REGION} --create-bucket-configuration LocationConstraint=$${AWS_REGION} || /bin/true
+      - aws s3 website s3://preview-gitea-org-blog-${DRONE_REPO_NAME}-${DRONE_PULL_REQUEST}/ --index-document index.html --error-document error.html || /bin/true
+
+  - name: "[PR] deploy website to S3 bucket"
+    when:
+      event:
+        - pull_request
+    pull: always
+    image: plugins/s3-sync
+    environment:
+      AWS_ACCESS_KEY_ID:
+        from_secret: preview_aws_access_token
+      AWS_SECRET_ACCESS_KEY:
+        from_secret: preview_aws_secret_access_key
+      AWS_REGION: eu-central-1
+    settings:
+      source: public/
+      target: /
+      region: eu-central-1
+      bucket: preview-gitea-org-blog-${DRONE_REPO_NAME}-${DRONE_PULL_REQUEST}
+      acl: public-read
+
+  - name: "[PR] Post comment to PR"
+    when:
+      event:
+        - pull_request
+    image: byrnedo/alpine-curl
+    environment:
+      GITEA_TOKEN:
+        from_secret: access_token
+      AWS_REGION: eu-central-1
+    commands:
+      # approach: check if comment already exists to prevent spamming in future runs
+      - 'COMMENTS=$(curl -sL -X GET -H "Authorization: token $GITEA_TOKEN" https://gitea.com/api/v1/repos/${DRONE_REPO_OWNER}/${DRONE_REPO_NAME}/issues/${DRONE_PULL_REQUEST}/comments)'
+      - 'if [[ $COMMENTS == "[]" ]]; then curl -sL -X POST -H "Authorization: token $GITEA_TOKEN" -H "Content-type: application/json" https://gitea.com/api/v1/repos/${DRONE_REPO_OWNER}/${DRONE_REPO_NAME}/issues/${DRONE_PULL_REQUEST}/comments -d "{\"body\": \"Website preview: http://preview-gitea-org-blog-${DRONE_REPO_NAME}-${DRONE_PULL_REQUEST}.s3-website.$${AWS_REGION}.amazonaws.com/\"}"; else echo -e "\n INFO: Comment already exist, doing nothing"; fi'
+
+  ### NB: not working as of 2023-02-06 due to Drone ignoring the Gitea webhook for PR close events: https://community.harness.io/t/closing-pull-request/13205
+  # - name: "[PR] Delete S3 bucket after closing PR"
+  #   image: byrnedo/alpine-curl
+  #   environment:
+  #     preview_aws_access_token:
+  #       from_secret: preview_aws_access_token
+  #     preview_aws_secret_access_key:
+  #       from_secret: preview_aws_secret_access_key
+  #     AWS_REGION: eu-central-1
+  #   commands:
+  #     - apk add --no-cache jq
+  #     # check if PR got closed
+  #     - "PR_STATE=$(curl https://gitea.com/api/v1/repos/${DRONE_REPO_OWNER}/${DRONE_REPO_NAME}/pulls/${DRONE_PULL_REQUEST} | jq -r .state)"
+  #     # delete S3 if PR is closed
+  #     - "if [[ $PR_STATE == 'closed' ]]; then aws s3 rb s3://preview-gitea-org-blog-${DRONE_REPO_NAME}-${DRONE_PULL_REQUEST} --force; else echo -e '\n INFO: PR not in state closed, doing nothing'; fi"
+
+volumes:
+  - name: cache
+    temp: {}