Using config file produces misleading comment with module paths from clone of main branch and the real module paths

[Tomasz-Kluczkowski]

Since config file can accept anything between 1 and infinite amount of projects it should work fine for just 1 project too.
This is not the case.

I am testing infracost for a variety of projects (terraform and terragrunt) and building a common ci-job template in gitlab.

For this issue we are considering a simple terraform project, with 1 folder terraform where the code is , with no multiple environments.

Consider this config file:

version: 0.1

projects:
  - path: ./terraform
    name: azure-infrastructure-costs

and running using this code (as per instructions here: https://gitlab.com/infracost/infracost-gitlab-ci/-/tree/master/examples/multi-project-config-file):

  script:
    - git clone $CI_REPOSITORY_URL --branch=$CI_MERGE_REQUEST_TARGET_BRANCH_NAME --single-branch /tmp/base

    - |
      cd /tmp/base
      infracost breakdown --config-file=${CONFIG_FILE} \
                          --format=json \
                          --out-file=infracost-base.json

    - |
      cd -
      infracost diff --config-file=${CONFIG_FILE} \
                     --compare-to=/tmp/base/infracost-base.json \
                     --format=json \
                     --out-file=infracost.json

    - |
      infracost comment gitlab --path=infracost.json \
                               --repo=$CI_PROJECT_PATH \
                               --merge-request=$CI_MERGE_REQUEST_IID \
                               --gitlab-server-url=$CI_SERVER_URL \
                               --gitlab-token=$GITLAB_API_TOKEN \
                               --behavior=update

Produces the following comment:

Infracost report

💰 Monthly cost will not change

Project	Module path	Cost change	New monthly cost
azure-infrastructure-costs	../../../../tmp/base/terraform	-£11	£0
azure-infrastructure-costs	terraform	+£11	£11

Where I would expect, that similarly to if I use --path=./terraform without config file, it will figure out there is only 1 project and provide result just for it.

We can see that it correctly states: Monthly cost will not change, but it does it for 2 projects:

• ../../../../tmp/base/terraform which is the path for the cloned code from the main branch
• terraform which is the path of the current branch.

Am I doing something wrong or using config file for 1 project was never considered but should?

[Tomasz-Kluczkowski]

Additionally I just tested this setup for a multi terraform project repo, and the result is similar to when using only one project - the reports are shown for base modules for main branch and for real modules.

💰 Monthly cost will not change

Project	Module path	Cost change	New monthly cost
management	../../../tmp/base/management/terraform	-£224	£0
management	management/terraform	+£224	£224
playground	../../../tmp/base/playground/terraform	-£30	£0
playground	playground/terraform	+£30	£30

[Tomasz-Kluczkowski]

So in conclusion, am I doing something wrong?

[aliscott]

@Tomasz-Kluczkowski what is your CONFIG_FILE variable set to? Also does it work if you copy the config file into /tmp/base before running infracost breakdown, e.g.:

    - |
      cp infracost.yml /tmp/base
      cd /tmp/base
      infracost breakdown --config-file=${CONFIG_FILE} \
                          --format=json \
                          --out-file=infracost-base.json

[Tomasz-Kluczkowski]

Hi,
I am running in gitlab. In my repo the .infracost.yml is in the root of the project.

CONFIG_FILE: ${CI_PROJECT_DIR}/.infracost.yml

[Tomasz-Kluczkowski]

I will try running with your instructions and report back.

[Tomasz-Kluczkowski]

ok I changed the code to be:

      cp .infracost.yml /tmp/base
      cd /tmp/base
      infracost breakdown --config-file=.infracost.yml \
                          --format=json \
                          --out-file=infracost-base.json

    - |
      cd -
      infracost diff --config-file=.infracost.yml \
                     --compare-to=/tmp/base/infracost-base.json \
                     --format=json \
                     --out-file=infracost.json

Which produced expected results for no changes to resources:

Infracost report

💰 Monthly cost will not change

_{This comment will be updated when code changes.}

And also when resources were changed:

💰 Monthly cost will increase by £9 📈

Project	Cost change	New monthly cost
playground	+£9 (+31%)	£40

So I think your solution is correct @aliscott . Should then infracost's documentation here: https://gitlab.com/infracost/infracost-gitlab-ci/-/tree/master/examples/multi-project-config-file be updated?