Merge pull request #22 from ewbankkit/add-parallelism-option-public

Add terraform '-parallelism=' option

DOCS.md

@@ -8,8 +8,9 @@ Use the Terraform plugin to apply the infrastructure configuration contained wit
  <key>=<value>` option.
 * `ca_cert` - ca cert to add to your environment to allow terraform to use internal/private resources
 * `sensitive` (default: `false`) - Whether or not to suppress terraform commands to stdout.
-* `role_arn_to_assume` - A role to assume before running the terraform commands
+* `role_arn_to_assume` - A role to assume before running the terraform commands.
 * `root_dir` - The root directory where the terraform files live. When unset, the top level directory will be assumed.
+* `parallelism` - The number of concurrent operations as Terraform walks its graph.
 
 The following is a sample Terraform configuration in your .drone.yml file:
 
@@ -113,3 +114,23 @@ deploy:
       app_version: 1.0.0
     root_dir: some/path/here
 ```
+
+## Parallelism
+You may want to limit the number of concurrent operations as Terraform walks its graph.
+If you want to change Terraform's default parallelism (currently equal to 10) then set the `parallelism` parameter.
+
+```yaml
+deploy:
+  terraform:
+    plan: false
+    remote:
+      backend: S3
+      config:
+        bucket: my-terraform-config-bucket
+        key: tf-states/my-project
+        region: us-east-1
+    vars:
+      app_name: my-project
+      app_version: 1.0.0
+    parallelism: 2
+```

Dockerfile

@@ -6,10 +6,10 @@
 FROM gliderlabs/alpine:3.2
 RUN apk-install ca-certificates git
 
-ENV TERRAFORM_VERSION 0.6.14
+ENV TERRAFORM_VERSION 0.6.16
 
 RUN apk update && \
-    wget -q "https://circle-artifacts.com/gh/andyshinn/alpine-pkg-glibc/6/artifacts/0/home/ubuntu/alpine-pkg-glibc/packages/x86_64/glibc-2.21-r2.apk" && \
+    wget -q "https://github.com/sgerrand/alpine-pkg-glibc/releases/download/2.21-r2/glibc-2.21-r2.apk" && \
     apk add --allow-untrusted glibc-2.21-r2.apk && \
     wget -q -O terraform.zip "https://releases.hashicorp.com/terraform/${TERRAFORM_VERSION}/terraform_${TERRAFORM_VERSION}_linux_amd64.zip" && \
     unzip terraform.zip -d /bin && \

main.go

@@ -26,6 +26,7 @@ type terraform struct {
 	Sensitive   bool              `json:"sensitive"`
 	RoleARN     string            `json:"role_arn_to_assume"`
 	RootDir     string            `json:"root_dir"`
+	Parallelism int               `json:"parallelism"`
 }
 
 type remote struct {
@@ -57,9 +58,9 @@ func main() {
 		commands = append(commands, remoteConfigCommand(remote))
 	}
 	commands = append(commands, getModules())
-	commands = append(commands, planCommand(vargs.Vars))
+	commands = append(commands, planCommand(vargs.Vars, vargs.Parallelism))
 	if !vargs.Plan {
-		commands = append(commands, applyCommand())
+		commands = append(commands, applyCommand(vargs.Parallelism))
 	}
 	commands = append(commands, deleteCache())
 
@@ -129,7 +130,7 @@ func getModules() *exec.Cmd {
 	)
 }
 
-func planCommand(variables map[string]string) *exec.Cmd {
+func planCommand(variables map[string]string, parallelism int) *exec.Cmd {
 	args := []string{
 		"plan",
 		"-out=plan.tfout",
@@ -138,17 +139,26 @@ func planCommand(variables map[string]string) *exec.Cmd {
 		args = append(args, "-var")
 		args = append(args, fmt.Sprintf("%s=%s", k, v))
 	}
+	if parallelism > 0 {
+		args = append(args, fmt.Sprintf("-parallelism=%d", parallelism))
+	}
 	return exec.Command(
 		"terraform",
 		args...,
 	)
 }
 
-func applyCommand() *exec.Cmd {
+func applyCommand(parallelism int) *exec.Cmd {
+	args := []string{
+		"apply",
+	}
+	if parallelism > 0 {
+		args = append(args, fmt.Sprintf("-parallelism=%d", parallelism))
+	}
+	args = append(args, "plan.tfout")
 	return exec.Command(
 		"terraform",
-		"apply",
+		args...,
-		"plan.tfout",
 	)
 }