Create an Output action (#108)

* Gather the terraform outputs and provide them as a step output to be used in further github actions

Author: jordanfinners

README.md

@@ -79,6 +79,7 @@ Inputs configure Terraform GitHub Actions to perform different actions.
 Outputs are used to pass information to subsequent GitHub Actions steps.
 
 * `tf_actions_plan_has_changes` - Whether or not the Terraform plan contained changes.
+* `tf_actions_output` - The Terraform outputs in JSON format.
 
 ## Secrets
 

action.yml

@@ -20,6 +20,8 @@ inputs:
 outputs:
   tf_actions_plan_has_changes:
     description: 'Whether or not the Terraform plan contained changes.'
+  tf_actions_output:
+    description: 'The Terraform outputs in JSON format.'
 runs:
   using: 'docker'
   image: './Dockerfile'

examples/output.md

@@ -0,0 +1,49 @@
+# Terraform Output
+
+If you need the outputs of your Terraform configuration later in your GitHub Actions workflow, you can use the `output` subcommand.
+
+```yaml
+name: 'Terraform GitHub Actions'
+on:
+  - push
+jobs:
+  terraform:
+    name: 'Terraform'
+    runs-on: ubuntu-latest
+    steps:
+      - name: 'Checkout'
+        uses: actions/checkout@master
+
+      - name: 'Terraform Outputs'
+        id: terraform
+        uses: hashicorp/terraform-github-actions@master
+        with:
+          tf_actions_version: 0.12.13
+          tf_actions_subcommand: 'outputs'
+          tf_actions_working_dir: '.'
+
+      - name: 'Use Terraform Output'
+        run: echo ${{ steps.terraform.outputs.tf_actions_output  }}
+
+      - name: 'Pull specific database name from outputs'
+        run: |
+          # Install jq in this shell
+          apt-get install jq
+
+          # Parse the outputs from the 'Terraform Outputs' step and grab the database name
+          DBNAME=$(echo ${{ steps.terraform.outputs.tf_actions_output }} | jq -r '.database.value.name')
+
+          # Will echo out 'test-database'
+          echo $DBNAME
+```
+
+In this example the `tf_actions_output` would look like:
+```json
+{
+  "database": {
+    "value": {
+      "name": "test-database"
+    }
+  }
+}
+```

src/main.sh

@@ -30,13 +30,13 @@ function parseInputs {
     echo "Input terraform_subcommand cannot be empty"
     exit 1
   fi
- 
+
   # Optional inputs
   tfWorkingDir="."
   if [ "${INPUT_TF_ACTIONS_WORKING_DIR}" != "" ] || [ "${INPUT_TF_ACTIONS_WORKING_DIR}" != "." ]; then
     tfWorkingDir=${INPUT_TF_ACTIONS_WORKING_DIR}
   fi
- 
+
   tfComment=0
   if [ "${INPUT_TF_ACTIONS_COMMENT}" == "1" ] || [ "${INPUT_TF_ACTIONS_COMMENT}" == "true" ]; then
     tfComment=1
@@ -71,6 +71,7 @@ function main {
   source ${scriptDir}/terraform_validate.sh
   source ${scriptDir}/terraform_plan.sh
   source ${scriptDir}/terraform_apply.sh
+  source ${scriptDir}/terraform_output.sh
 
   parseInputs
   cd ${GITHUB_WORKSPACE}/${tfWorkingDir}
@@ -96,6 +97,10 @@ function main {
       installTerraform
       terraformApply "${*}"
       ;;
+    output)
+      installTerraform
+      terraformOutput ${*}
+      ;;
     *)
       echo "Error: Must provide a valid value for terraform_subcommand"
       exit 1

src/terraform_output.sh

@@ -0,0 +1,23 @@
+#!/bin/bash
+
+function terraformOutput {
+  # Gather the output of `terraform output`.
+  echo "output: info: gathering all the outputs for the Terraform configuration in ${tfWorkingDir}"
+  outputOutput=$(terraform output -json ${*} 2>&1)
+  outputExitCode=${?}
+
+  # Exit code of 0 indicates success. Print the output and exit.
+  if [ ${outputExitCode} -eq 0 ]; then
+    echo "output: info: successfully gathered all the outputs for the Terraform configuration in ${tfWorkingDir}"
+    echo "${outputOutput}"
+    echo
+    echo ::set-output name=tf_actions_output::${outputOutput}
+    exit ${outputExitCode}
+  fi
+
+  # Exit code of !0 indicates failure.
+  echo "output: error: failed to gather all the outputs for the Terraform configuration in ${tfWorkingDir}"
+  echo "${outputOutput}"
+  echo
+  exit ${outputExitCode}
+}