Post Run: Error: Value cannot be null. (Parameter 'target')

Describe the bug Some of our “Post job cleanup” steps are failing when using actions/cache@v2 (https://github.com/actions/cache). Unclear if the issue is related to that action or with the runner.

The error manifests as the following:

Post job cleanup.
Error: Value cannot be null. (Parameter 'target')
Post job cleanup.
Cache hit occurred on the primary key Linux-terraform-, not saving cache.
Post job cleanup.

To Reproduce Define a composite action like the following:

name: "terraform-apply"
description: "Execute terraform apply against a working directory."
inputs:
  backend-bucket:
    description: "The name of the terraform backend state bucket."
    required: true
  backend-dynamodb-table:
    description: "The name of the DynamoDB table which stores the terraform backend state locks."
    required: true
  backend-kms-key-id:
    description: "The ID of the KMS key which is used to encrypt/decrypt the terraform backend state files."
    required: true
  input-variables-file:
    description: "The filename of a .tfvars file, relative to the working directory."
    required: false
  working-directory:
    description: "The working directory to use when running terraform apply."
    required: true
  workspace:
    default: "${{ github.event.number }}"
    description: "The terraform workspace to use."
    required: true
outputs:
  exitcode:
    description: "The exit code of the call to the terraform binary."
    value: ${{ steps.apply.outputs.exitcode }}
  stderr:
    description: "The STDERR stream of the call to the terraform binary."
    value: ${{ steps.apply.outputs.stderr }}
  stdout:
    description: "The STDOUT stream of the call to the terraform binary."
    value: ${{ steps.apply.outputs.stdout }}
runs:
  using: "composite"
  steps:
    - name: "Create Terraform cache directory"
      env:
        TF_PLUGIN_CACHE_DIR: "${{ github.workspace }}/.terraform.d/plugin-cache"
      run: mkdir --parents "$TF_PLUGIN_CACHE_DIR"
      shell: bash
    - name: "Setup Terraform cache"
      env:
        TF_PLUGIN_CACHE_DIR: "${{ github.workspace }}/.terraform.d/plugin-cache"
      uses: actions/cache@v2
      with:
        path: ${{ env.TF_PLUGIN_CACHE_DIR }}
        key: ${{ runner.os }}-terraform-${{ hashFiles('${{ inputs.working-directory }}/.terraform.lock.hcl') }}
    - uses: hashicorp/setup-terraform@v1
    - run: terraform version
      shell: bash
    - name: "Lint"
      run: terraform fmt -check -diff -recursive
      shell: bash
      working-directory: "${{ inputs.working-directory }}"
    - name: "Apply"
      id: apply
      env:
        TF_IN_AUTOMATION: "true"
        TF_PLUGIN_CACHE_DIR: "${{ github.workspace }}/.terraform.d/plugin-cache"
      working-directory: "${{ inputs.working-directory }}"
      run: |
        terraform init -input=false -no-color \
          -backend-config="bucket=${{ inputs.backend-bucket }}" \
          -backend-config="dynamodb_table=${{ inputs.backend-dynamodb-table }}" \
          -backend-config="key=${{ inputs.working-directory }}.tfstate" \
          -backend-config="kms_key_id=${{ inputs.backend-kms-key-id }}"
        terraform workspace select "${{ inputs.workspace }}" || terraform workspace new "${{ inputs.workspace }}"
        if [[ -n "${{ inputs.input-variables-file }}" ]]; then
          terraform apply -auto-approve -no-color -var-file="${{ inputs.input-variables-file }}"
        else
          terraform apply -auto-approve -no-color
        fi
        terraform output -json
      shell: bash

And then invoke that action in a workflow:

    - name: "Apply management resources"
      id: management
      uses: ./.github/actions/terraform-apply
      with:
        backend-bucket: "${{ env.TF_BACKEND_STATE_BUCKET }}"
        backend-dynamodb-table: "${{ env.TF_DYNAMO_DB_LOCK_TABLE }}"
        backend-kms-key-id: "${{ env.TF_KMS_KEY_ID }}"
        working-directory: "${{ inputs.project-path }}/infra/terraform/management"

This results in the above error during the “Post Run” phase of the job. An example run with this error: https://github.com/solarmosaic-internal/mosaic/runs/4098670986 (note: this is a private organization).

If the following is commented out from the composite action:

#    - name: "Create Terraform cache directory"
#      env:
#        TF_PLUGIN_CACHE_DIR: "${{ github.workspace }}/.terraform.d/plugin-cache"
#      run: mkdir --parents "$TF_PLUGIN_CACHE_DIR"
#      shell: bash
#    - name: "Setup Terraform cache"
#      env:
#        TF_PLUGIN_CACHE_DIR: "${{ github.workspace }}/.terraform.d/plugin-cache"
#      uses: actions/cache@v2
#      with:
#        path: ${{ env.TF_PLUGIN_CACHE_DIR }}
#        key: ${{ runner.os }}-terraform-${{ hashFiles('${{ inputs.working-directory }}/.terraform.lock.hcl') }}

The workflow succeeds without error.

Expected behavior I expect the “Post run” steps to succeed. Additionally, if they do fail, I would expect a better indication of where the failure is happening and why. It’s not clear to me if this is an issue with actions/cache, or the runner, or both.

Runner Version and Platform

Current runner version: '2.284.0'
Operating System
  Ubuntu
  20.04.3
  LTS
Virtual Environment
  Environment: ubuntu-20.04
  Version: 20211101.1
  Included Software: https://github.com/actions/virtual-environments/blob/ubuntu20/20211101.1/images/linux/Ubuntu2004-README.md
  Image Release: https://github.com/actions/virtual-environments/releases/tag/ubuntu20%2F20211101.1
Virtual Environment Provisioner
  1.0.0.0-master-20211022-1
GITHUB_TOKEN Permissions
  Actions: write
  Checks: write
  Contents: write
  Deployments: write
  Discussions: write
  Issues: write
  Metadata: read
  Packages: write
  Pages: write
  PullRequests: write
  RepositoryProjects: write
  SecurityEvents: write
  Statuses: write

What’s not working?

Potentially related to https://github.com/actions/runner/pull/1438

Job Log Output

2021-11-03T22:03:50.0333306Z Post job cleanup.
2021-11-03T22:03:50.0386558Z Post job cleanup.
2021-11-03T22:03:50.0517077Z ##[error]Value cannot be null. (Parameter 'target')
2021-11-03T22:03:50.8698990Z Post job cleanup.
2021-11-03T22:03:51.0061804Z Cache hit occurred on the primary key Linux-terraform-, not saving cache.
2021-11-03T22:03:51.0208763Z Post job cleanup.

Runner and Worker’s Diagnostic Logs

Not sure how to access diagnostic logs.

[fhammerl]

@TingluoHuang it could be related to either https://github.com/actions/runner/pull/1433 or https://github.com/actions/runner/pull/1438.

@solarmosaic-kflorence did this workflow ever fail on the previous runner version (2.283.3) or did it ever run successfully on the current one?

[fhammerl]

@solarmosaic-kflorence Thanks for confirming it, we’ll be tracking this issue as a regression.

As an alternative workaround, perhaps you could try invoking is as a global action?

    - name: "Apply management resources"
      id: management
      uses: owner/repo/.github/actions/terraform-apply@main # <--
      with:
...