tf-plan-summary-action

Parses terraform show -json output and writes a human-readable summary to the GitHub Actions job summary — a diff table plus a collapsible, terraform plan-style field-level diff. The plan parsing and rendering are provided by the importable unum/pkg/terraform package, so the action is a single self-contained Go build with no runtime CLI dependency.

Example output

The ## Terraform Plan heading, the Terraform will perform… preamble and the Plan: summary line sit outside the code block. Inside the fenced diff block, change markers are in column 0 so GitHub colours the lines: + created (green), - destroyed (red) and ! updated-in-place (amber):

---

Terraform Plan

Terraform will perform the following actions:

    # aws_instance.web will be created
+   resource "aws_instance" "web" {
+     ami           = "ami-123"
+     arn           = (known after apply)
+     instance_type = "t3.micro"
+   }

    # aws_s3_bucket.assets will be updated in-place
!   resource "aws_s3_bucket" "assets" {
!     versioning {
!       enabled = false -> true
!     }
      # (1 unchanged attribute hidden)
!   }

    # aws_instance.legacy will be destroyed
-   resource "aws_instance" "legacy" {
-     ami           = "ami-old" -> null
-     instance_type = "t2.micro" -> null
-   }

Plan: 2 to add, 1 to change, 1 to destroy, 0 to replace.

---

Usage

- name: Generate plan JSON
  run: terraform show -json tfplan > plan.json

- name: Terraform Plan Summary
  uses: danielriddell21/tf-plan-summary-action@v2.0.2
  with:
    plan-file: plan.json

Inputs

Input	Description	Required	Default
plan-file	Path to the terraform show -json output file, relative to the workspace root.	No	plan.json

Example workflow

jobs:
  plan:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - uses: hashicorp/setup-terraform@v3
        with:
          terraform_version: "~1.6"

      - name: init
        run: terraform init

      - name: plan
        run: |
          terraform plan -no-color -input=false -out=tfplan
          terraform show -json tfplan > plan.json

      - name: Terraform Plan Summary
        uses: danielriddell21/tf-plan-summary-action@v2.0.2
        with:
          plan-file: plan.json