use consistent TF version when invoking TF

- ensure the generation of the `example` directory data is done in a
  consistent, reproducible fashion
- ensure GH Actions uses the same version of TF expected by the `example` directory
- add plan and plan JSON files to source control, for testing purposes

.github/workflows/demo.yml

@@ -11,49 +11,54 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
-
-    - name: Setup Terraform
-      uses: hashicorp/setup-terraform@v2
-      with:
-        terraform_wrapper: false
-
-    - name: Install terraform-plan-summary
-      run: |
-        REPO="dineshba/tf-summarize"
-        curl -LO https://github.com/$REPO/releases/latest/download/tf-summarize_linux_amd64.zip
-        tmpDir=$(mktemp -d -t tmp.XXXXXXXXXX)
-        mv tf-summarize_linux_amd64.zip $tmpDir
-        cd $tmpDir
-        unzip tf-summarize_linux_amd64.zip
-        chmod +x tf-summarize
-        echo $PWD >> $GITHUB_PATH
-
-    - name: Print tf-summarize version and help
-      run: |
-        tf-summarize -v
-        tf-summarize -h
-
-    - name: Terraform Init
-      run: terraform init
-      working-directory: ./example
-
-    - name: Terraform Plan
-      run: terraform plan -out=tfplan -refresh=false # -refresh=false is only for demo workflow
-      working-directory: ./example
-
-    - name: summary in table format
-      run: terraform show -json tfplan | tf-summarize
-      working-directory: ./example
-
-    - name: summary in tree format
-      run: terraform show -json tfplan | tf-summarize -tree
-      working-directory: ./example
-
-    - name: summary in separate tree format
-      run: terraform show -json tfplan | tf-summarize -separate-tree
-      working-directory: ./example
-
-    - name: summary in draw visual tree format
-      run: terraform show -json tfplan | tf-summarize -tree -draw
-      working-directory: ./example
+      - uses: actions/checkout@v3
+
+      - name: Set Terraform version
+        id: set-terraform-version
+        run: echo "terraform-version=$(cat example/.terraform-version)" >> $GITHUB_OUTPUT
+
+      - name: Setup Terraform
+        uses: hashicorp/setup-terraform@v2
+        with:
+          terraform_wrapper: false
+          terraform_version: ${{ steps.set-terraform-version.outputs.terraform-version }}
+
+      - name: Install terraform-plan-summary
+        run: |
+          REPO="dineshba/tf-summarize"
+          curl -LO https://github.com/$REPO/releases/latest/download/tf-summarize_linux_amd64.zip
+          tmpDir=$(mktemp -d -t tmp.XXXXXXXXXX)
+          mv tf-summarize_linux_amd64.zip $tmpDir
+          cd $tmpDir
+          unzip tf-summarize_linux_amd64.zip
+          chmod +x tf-summarize
+          echo $PWD >> $GITHUB_PATH
+
+      - name: Print tf-summarize version and help
+        run: |
+          tf-summarize -v
+          tf-summarize -h
+
+      - name: Terraform Init
+        run: terraform init
+        working-directory: ./example
+
+      - name: Terraform Plan
+        run: terraform plan -out=tfplan -refresh=false # -refresh=false is only for demo workflow
+        working-directory: ./example
+
+      - name: summary in table format
+        run: terraform show -json tfplan | tf-summarize
+        working-directory: ./example
+
+      - name: summary in tree format
+        run: terraform show -json tfplan | tf-summarize -tree
+        working-directory: ./example
+
+      - name: summary in separate tree format
+        run: terraform show -json tfplan | tf-summarize -separate-tree
+        working-directory: ./example
+
+      - name: summary in draw visual tree format
+        run: terraform show -json tfplan | tf-summarize -tree -draw
+        working-directory: ./example

Makefile

@@ -1,3 +1,5 @@
+TERRAFORM_VERSION:=$(shell cat example/.terraform-version)
+
 .PHONY: help
 help: ## prints help (only for tasks with comment)
 	@grep -E '^[a-zA-Z._-]+:.*?## .*$$' $(MAKEFILE_LIST) | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'
@@ -17,4 +19,22 @@ test: lint
 i: install ## build and install to /usr/local/bin/
 
 lint:
-	golangci-lint run --timeout 10m -v
+	golangci-lint run --timeout 10m -v
+
+define generate-example
+	docker run \
+		--interactive \
+		--tty \
+		--volume $(shell pwd):/src \
+		--workdir /src/example \
+		--entrypoint /bin/sh \
+		hashicorp/terraform:$(1) \
+			-c \
+				"terraform init && \
+				terraform plan -out tfplan && \
+				terraform show -json tfplan > tfplan.json"
+endef
+
+example:
+	$(call generate-example,$(TERRAFORM_VERSION))
+.PHONY: example

example/.terraform-version

@@ -0,0 +1 @@
+1.1.4