1 简介

Terraform是管理许多平台的基础设施的工具，如AWS、GCP和Azure。这篇文章将讲解如何通过Terraform来管理GCP Pub/Sub。

创建GCP项目请参考：初始化一个GCP项目并用gcloud访问操作

2 Terraform创建Pub/Sub

2.1 下载Terraform插件

我们需要安装GCP的Terraform插件来管理GCP资源：

# 设置插件目录
$ export TERRAFORM_PLUGIN=/Users/larry/Software/terraform/plugins
# 创建目录
$ mkdir -p ${TERRAFORM_PLUGIN}/registry.terraform.io/hashicorp/google/4.0.0/darwin_amd64
$ cd ${TERRAFORM_PLUGIN}/registry.terraform.io/hashicorp/google/4.0.0/darwin_amd64
# 下载
$ wget https://releases.hashicorp.com/terraform-provider-google/4.0.0/terraform-provider-google_4.0.0_darwin_amd64.zip
# 解压
$ unzip terraform-provider-google_4.0.0_darwin_amd64.zip

2.2 准备Terraform代码

需要提供Terraform代码理管理Pub/Sub，更多细节请参考： Terrafrom GCP.

版本文件version.tf:

terraform {required_version = "= 1.0.11"required_providers {google = {source  = "hashicorp/google"version = "= 4.0.0"}}
}

主文件main.tf:

provider "google" {project     = "pkslow"
}resource "google_pubsub_topic" "pkslow-poc" {name = "pkslow-poc"
}resource "google_pubsub_subscription" "pkslow-poc" {name  = "pkslow-poc"topic = google_pubsub_topic.pkslow-poc.namelabels = {foo = "bar"}# 20 minutesmessage_retention_duration = "1200s"retain_acked_messages      = trueack_deadline_seconds = 20expiration_policy {ttl = "300000.5s"}retry_policy {minimum_backoff = "10s"}enable_message_ordering    = true
}

2.3 初始化和变更

指定插件目录初始化：

$ terraform init -plugin-dir=${TERRAFORM_PLUGIN}

使变更生效，就会在GCP上创建对应的资源：

$ terraform apply -auto-approve

如果没有发生错误，则意味着创建成功，我们检查一下：

$ gcloud pubsub topics list
---
name: projects/pkslow/topics/pkslow-poc$ gcloud pubsub subscriptions list
---
ackDeadlineSeconds: 20
enableMessageOrdering: true
expirationPolicy:ttl: 300000.500s
labels:foo: bar
messageRetentionDuration: 1200s
name: projects/pkslow/subscriptions/pkslow-poc
pushConfig: {}
retainAckedMessages: true
retryPolicy:maximumBackoff: 600sminimumBackoff: 10s
topic: projects/pkslow/topics/pkslow-poc

注意：我们并没有提供任何密码或密钥，那Terraform怎么可以直接操作我的GCP资源呢？因为它会根据环境变量GOOGLE_APPLICATION_CREDENTIALS来获取。

3 发送和接收消息

我们通过gcloud来发送消息到Pub/Sub上：

$ gcloud pubsub topics publish pkslow-poc --message="www.pkslow.com"
messageIds:
- '3491736520339885'$ gcloud pubsub topics publish pkslow-poc --message="Larry Deng"
messageIds:
- '3491738650256958'$ gcloud pubsub topics publish pkslow-poc --message="Hi, pkslower"
messageIds:
- '3491739306095970'

从Pub/Sub拉取消息：

$ gcloud pubsub subscriptions pull pkslow-poc --auto-ack

我们还能在GCP界面上监控对应的队列，十分方便：

4 代码

代码在 GitHub上： https://github.com/LarryDpk/pkslow-samples