问题
Our CloudFormation templates are stored in GitHub. Inside CodePipeline we're using GitHub as our Source, but we can't reference nested CloudFormation Stacks when they're not stored on S3.
How can we reference CloudFormation nested Stacks when using GitHub as our source in CodePipeline?
If this is not possible, how can we upload the CloudFormation Templates from GitHub to S3 between the Source Stage (from GitHub) and the Deploy Stage in CodePipeline?
回答1:
There are two approaches I can think of to reference nested CloudFormation Stacks from a GitHub source for a CodePipeline deployment:
1. pre-commit Git hook
Add a pre-commit client-side Git hook that runs aws cloudformation package on your template, committing a generated template with the S3 reference to your GitHub repository alongside the changes to the source template.
The benefit to this approach is that you can leverage the existing template-rewriting logic in aws cloudformation package, and you don't have to modify your existing CodePipeline configuration.
2. Lambda pipeline Stage
Add a Lambda-based pipeline Stage that extracts the specified nested-stack template file from the GitHub Source Artifact and uploads it to a specified location in S3 referenced in the parent stack template.
The benefit to this approach is that the Pipeline will remain entirely self-contained, without any extra pre-processing step required by the committer.
I've published a complete reference example implementation to wjordan/aws-codepipeline-nested-stack:
AWSTemplateFormatVersion: 2010-09-09
Description: Infrastructure Continuous Delivery with CodePipeline and CloudFormation, with a project containing a nested stack.
Parameters:
ArtifactBucket:
Type: String
Description: Name of existing S3 bucket for storing pipeline artifacts
StackFilename:
Type: String
Default: cfn-template.yml
Description: CloudFormation stack template filename in the Git repo
GitHubOwner:
Type: String
Description: GitHub repository owner
GitHubRepo:
Type: String
Default: aws-codepipeline-nested-stack
Description: GitHub repository name
GitHubBranch:
Type: String
Default: master
Description: GitHub repository branch
GitHubToken:
Type: String
Description: GitHub repository OAuth token
NestedStackFilename:
Type: String
Description: GitHub filename (and S3 Object Key) for nested stack template.
Default: nested.yml
Resources:
Pipeline:
Type: AWS::CodePipeline::Pipeline
Properties:
RoleArn: !GetAtt [PipelineRole, Arn]
ArtifactStore:
Type: S3
Location: !Ref ArtifactBucket
Stages:
- Name: Source
Actions:
- Name: Source
ActionTypeId:
Category: Source
Owner: ThirdParty
Version: 1
Provider: GitHub
Configuration:
Owner: !Ref GitHubOwner
Repo: !Ref GitHubRepo
Branch: !Ref GitHubBranch
OAuthToken: !Ref GitHubToken
OutputArtifacts: [Name: Template]
RunOrder: 1
- Name: Deploy
Actions:
- Name: S3Upload
ActionTypeId:
Category: Invoke
Owner: AWS
Provider: Lambda
Version: 1
InputArtifacts: [Name: Template]
Configuration:
FunctionName: !Ref S3UploadObject
UserParameters: !Ref NestedStackFilename
RunOrder: 1
- Name: Deploy
RunOrder: 2
ActionTypeId:
Category: Deploy
Owner: AWS
Version: 1
Provider: CloudFormation
InputArtifacts: [Name: Template]
Configuration:
ActionMode: REPLACE_ON_FAILURE
RoleArn: !GetAtt [CFNRole, Arn]
StackName: !Ref AWS::StackName
TemplatePath: !Sub "Template::${StackFilename}"
Capabilities: CAPABILITY_IAM
ParameterOverrides: !Sub |
{
"ArtifactBucket": "${ArtifactBucket}",
"StackFilename": "${StackFilename}",
"GitHubOwner": "${GitHubOwner}",
"GitHubRepo": "${GitHubRepo}",
"GitHubBranch": "${GitHubBranch}",
"GitHubToken": "${GitHubToken}",
"NestedStackFilename": "${NestedStackFilename}"
}
CFNRole:
Type: AWS::IAM::Role
Properties:
AssumeRolePolicyDocument:
Statement:
- Action: ['sts:AssumeRole']
Effect: Allow
Principal: {Service: [cloudformation.amazonaws.com]}
Version: '2012-10-17'
Path: /
ManagedPolicyArns:
# TODO grant least privilege to only allow managing your CloudFormation stack resources
- "arn:aws:iam::aws:policy/AdministratorAccess"
PipelineRole:
Type: AWS::IAM::Role
Properties:
AssumeRolePolicyDocument:
Statement:
- Action: ['sts:AssumeRole']
Effect: Allow
Principal: {Service: [codepipeline.amazonaws.com]}
Version: '2012-10-17'
Path: /
Policies:
- PolicyName: CodePipelineAccess
PolicyDocument:
Version: '2012-10-17'
Statement:
- Action:
- 's3:*'
- 'cloudformation:*'
- 'iam:PassRole'
- 'lambda:*'
Effect: Allow
Resource: '*'
Dummy:
Type: AWS::CloudFormation::WaitConditionHandle
NestedStack:
Type: AWS::CloudFormation::Stack
Properties:
TemplateURL: !Sub "https://s3.amazonaws.com/${ArtifactBucket}/${NestedStackFilename}"
S3UploadObject:
Type: AWS::Lambda::Function
Properties:
Description: Extracts and uploads the specified InputArtifact file to S3.
Handler: index.handler
Role: !GetAtt LambdaExecutionRole.Arn
Code:
ZipFile: !Sub |
var exec = require('child_process').exec;
var AWS = require('aws-sdk');
var codePipeline = new AWS.CodePipeline();
exports.handler = function(event, context, callback) {
var job = event["CodePipeline.job"];
var s3Download = new AWS.S3({
credentials: job.data.artifactCredentials,
signatureVersion: 'v4'
});
var s3Upload = new AWS.S3({
signatureVersion: 'v4'
});
var jobId = job.id;
function respond(e) {
var params = {jobId: jobId};
if (e) {
params['failureDetails'] = {
message: JSON.stringify(e),
type: 'JobFailed',
externalExecutionId: context.invokeid
};
codePipeline.putJobFailureResult(params, (err, data) => callback(e));
} else {
codePipeline.putJobSuccessResult(params, (err, data) => callback(e));
}
}
var filename = job.data.actionConfiguration.configuration.UserParameters;
var location = job.data.inputArtifacts[0].location.s3Location;
var bucket = location.bucketName;
var key = location.objectKey;
var tmpFile = '/tmp/file.zip';
s3Download.getObject({Bucket: bucket, Key: key})
.createReadStream()
.pipe(require('fs').createWriteStream(tmpFile))
.on('finish', ()=>{
exec(`unzip -p ${!tmpFile} ${!filename}`, (err, stdout)=>{
if (err) { respond(err); }
s3Upload.putObject({Bucket: bucket, Key: filename, Body: stdout}, (err, data) => respond(err));
});
});
};
Timeout: 30
Runtime: nodejs4.3
LambdaExecutionRole:
Type: AWS::IAM::Role
Properties:
AssumeRolePolicyDocument:
Version: '2012-10-17'
Statement:
- Effect: Allow
Principal: {Service: [lambda.amazonaws.com]}
Action: ['sts:AssumeRole']
Path: /
ManagedPolicyArns:
- "arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole"
- "arn:aws:iam::aws:policy/AWSCodePipelineCustomActionAccess"
Policies:
- PolicyName: S3Policy
PolicyDocument:
Version: '2012-10-17'
Statement:
- Effect: Allow
Action:
- 's3:PutObject'
- 's3:PutObjectAcl'
Resource: !Sub "arn:aws:s3:::${ArtifactBucket}/${NestedStackFilename}"
回答2:
Besides the solution with a lambda stage, a simple approach is to use CodeBuild and AWS SAM.
In the main CloudFormation template (let's call it main.yaml), use 'Transform: AWS::Serverless-2016-10-31'
AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Resources:
NestedTemplate:
AWS::CloudFormation::Stack
Properties:
TemplateUri: ./nested-template.yaml
Note that you just need to put the relative path to the child template instead of an absolution s3 uri.
Add a CodeBuild stage with the following buildspecification.yaml
version: 0.1
phases:
build:
commands:
aws cloudformation package --template-file main.yaml --output-template-file transformed_main.yaml --s3-bucket my_bucket
artifacts:
type: zip
files:
- transformed_main.yaml
The build command 'aws cloudformation package' will upload the nested-template.yaml to the s3 bucket 'my_bucket' and inject the absolute s3 uri to the transformed template.
In the CloudFormation deployment stage, use 'Create change set' and 'Execute change set' to create the stack. Note that 'Create or update stack' does not work for 'Transform: AWS::Serverless-2016-10-31'.
Here are the docs you may find useful:
- http://docs.aws.amazon.com/cli/latest/reference/cloudformation/package.html
- http://docs.aws.amazon.com/lambda/latest/dg/automating-deployment.html
The second doc shows how to deploy a lambda function, but it is essentially the same to reference a nested stack.
来源：https://stackoverflow.com/questions/41590687/codepipeline-how-to-reference-nested-cloudformation-stacks-from-github-as-sourc