Show plan in PR comment

.github/workflows/terraform.yaml

@@ -2,6 +2,8 @@ name: Terraform
 
 on:
   push:
+    branches: [main]
+  pull_request:
 
 jobs:
   run:
@@ -12,6 +14,7 @@ jobs:
       pull-requests: write
     env:
       TF_HTTP_PASSWORD: ${{ github.token }}
+      TF_IN_AUTOMATION: "true"
     steps:
       - name: Checkout
         uses: actions/checkout@v3
@@ -21,4 +24,71 @@ jobs:
           terraform_version: "1.6.6"
 
       - run: terraform init
-      - run: terraform plan
+
+      - run: terraform plan -out=tfplan
+      - run: terraform apply tfplan
+        if: ${{ github.event_name == 'push' && github.ref_name == 'main' }}
+
+      - run: terraform show -no-color tfplan > summary.txt
+        if: ${{ github.event_name == 'pull_request' }}
+      - name: Show plan on PR
+        uses: actions/github-script@v7
+        if: ${{ github.event_name == 'pull_request' }}
+        with:
+          github-token: ${{ github.token }}
+          script: |
+            const { repository: { pullRequest: { comments } } } = await github.graphql(`
+              query($owner:String!, $name:String!, $pr:Int!) {
+                repository(owner:$owner, name:$name) {
+                  pullRequest(number:$pr) {
+                    comments(last: 10) {
+                      nodes {
+                        id,
+                        minimizedReason
+                        author {
+                          ...on Bot {
+                            login
+                          }
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+            `, {
+              owner: context.repo.owner,
+              name: context.repo.repo,
+              pr: context.issue.number,
+            })
+
+            const commentsToHide = comments.nodes.filter((comment) => {
+              return !comment.minimizedReason && comment.author.login == "github-actions"
+            })
+            console.log({ commentsToHide })
+            await github.graphql(`
+              mutation {
+                ${commentsToHide.map((c,i) =>
+                  `c${i}: minimizeComment(input: { subjectId: "${c.id}", classifier: OUTDATED }) {
+                    clientMutationId
+                  }
+                  `
+                ).join("")}
+              }
+            `)
+
+            const fs = require('fs').promises
+            const plan = await fs.readFile('summary.txt', 'utf-8')
+
+            const codefence = "```"
+            const body = `
+            🏗️ Terraform Plan
+            ${codefence}
+            ${plan.trim("\n")}
+            ${codefence}`
+
+            github.rest.issues.createComment({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body,
+            })