AWS CodePipeline CodeBuild SAM Lambda

Question

I have a PipeLine for Lambda (NodeJS) Auto Deploy from CodeCommit.

My buildspec.yml

version: 0.1
phases:
 install:
  commands:
    - npm install
    - aws cloudformation package --template-file samTemplate.yaml --s3-bucket codepipeline-551 --output-template-file outputSamTemplate.yaml
artifacts:
  type: zip
  files:
    - samTemplate.yaml
    - outputSamTemplate.yaml

My samTemplate.yaml

AWSTemplateFormatVersion: '2010-09-09'
Transform: 'AWS::Serverless-2016-10-31'
Description: An AWS Serverless Specification template describing your function.
Resources:
  KashIoTLambda:
    Type: 'AWS::Serverless::Function'
    Properties:
      Handler: lambda.handler
      Runtime: nodejs8.10
      CodeUri: ./
      Description: ''
      MemorySize: 128
      Timeout: 3
      Role: 'arn:aws:iam::1234:role/abc-backend'
      Events:
        Api1:
          Type: Api
          Properties:
            Path: '/{proxy+}'
            Method: OPTIONS
        Api2:
          Type: Api
          Properties:
            Path: /MyResource
            Method: ANY
      Environment:
        Variables:
          REGION: ap-south-1

The policy attached to the role mentioned for CodeBuild gives access to All Resources & All S3 commands.

However, I have the following error from build logs

[Container] 2019/01/03 13:25:39 Running command npm install
added 122 packages in 3.498s
 [Container] 2019/01/03 13:25:44 Running command aws cloudformation package --template-file samTemplate.yaml --s3-bucket codepipeline-551 --output-template-file outputSamTemplate.yaml
 Unable to upload artifact ./ referenced by CodeUri parameter of ABCLambda resource.
An error occurred (AccessDenied) when calling the PutObject operation: Access Denied
 [Container] 2019/01/03 13:25:46 Command did not exit successfully aws cloudformation package --template-file samTemplate.yaml --s3-bucket codepipeline-551 --output-template-file outputSamTemplate.yaml exit status 255
[Container] 2019/01/03 13:25:46 Phase complete: INSTALL Success: false
[Container] 2019/01/03 13:25:46 Phase context status code: COMMAND_EXECUTION_ERROR Message: Error while executing command: aws cloudformation package --template-file samTemplate.yaml --s3-bucket codepipeline-551 --output-template-file outputSamTemplate.yaml. Reason: exit status 255

Answer 1

Check the policies/permissions on the bucket itself.

If you were like me, you may have selected the default location option as the artifact store in the pipeline settings when you first set it up. In which case, there may be policies on the S3 bucket itself blocking access.

For me, once I removed the bucket policy the unable to upload artifact error was resolved and my build process went on to complete successfully.

I hope this helps you.