Terraform中AWS CodePipeline的ignore_changes对OAuthToken不生效问题

Problem Description #

I've configured an AWS CodePipeline in Terraform with the following snippet:

resource "aws_codepipeline" "codepipeline" {
  name = "Cool Pipeline"
  # ... other configuration ...

  stage {
    name = "Source"
    # ... other stage configuration ...

    action {
      name = "Source"
      # ... other action configuration ...

      configuration {
        Owner       = "Me"
        Repo        = "<git-repo-uri>"
        Branch      = "develop"
        OAuthToken  = "b3287d649a28374e9283c749cc283ad74" # Fake token for example
      }
    }
  }

  lifecycle {
    ignore_changes = "OAuthToken"
  }
}

Since the AWS API returns **** instead of the actual OAuthToken when Terraform fetches state, running terraform plan always shows a pending update for this field:

module.modulename.aws_codepipeline.codepipeline
  stage.0.action.0.configuration.%: "3" => "4"
  stage.0.action.0.configuration.OAuthToken: "" => "b3287d649a28374e9283c749cc283ad74"

I've tried multiple ignore_changes configurations without success:

• ["OAuthToken"]
• ["oauthtoken"]
• ["stage.action.configuration.OAuthToken"]

How can I get ignore_changes to work for this OAuthToken field?

Solution #

The issue here is that both stage and action are list (array) types in the aws_codepipeline resource. Terraform can't resolve generic paths like stage.action.configuration.OAuthToken because it needs to target the specific index of the stage and action that contains the OAuthToken.

Correct Configuration #

Use the full, index-specific path in your ignore_changes block. Since your example uses the first stage (stage.0) and first action within that stage (action.0), the correct syntax is:

lifecycle {
  ignore_changes = [
    stage[0].action[0].configuration.OAuthToken,
  ]
}

Or using string-style path notation (both formats work):

lifecycle {
  ignore_changes = ["stage.0.action.0.configuration.OAuthToken"]
}

Why This Works #

• stage[0] targets the first stage in your pipeline (lists are 0-indexed in Terraform)
• action[0] targets the first action within that stage
• This precise path tells Terraform to ignore any changes to the OAuthToken field in that specific action's configuration, perfectly matching the structure shown in your terraform plan output.

For Multiple Stages/Actions #

If you have multiple stages or actions with OAuthToken fields, you can add each specific path to the ignore_changes list:

lifecycle {
  ignore_changes = [
    stage[0].action[0].configuration.OAuthToken,
    stage[1].action[0].configuration.OAuthToken,
    # Add more paths as needed
  ]
}

内容的提问来源于stack exchange，提问作者Wrench