Getting `Argument list too long` in GitHub Actions - github

Question

I am following HashiCorp's learning guide on how to set up GitHub Actions and terraform. All is running great besides the step to update the PR with the Terraform Plan.
I am hitting the following error:
An error occurred trying to start process '/home/runner/runners/2.287.1/externals/node12/bin/node' with working directory '/home/runner/work/ccoe-aws-ou-scp-manage/ccoe-aws-ou-scp-manage'. Argument list too long
The code I am using is:
- uses: actions/github-script#0.9.0
if: github.event_name == 'pull_request'
env:
PLAN: "terraform\n${{ steps.plan.outputs.stdout }}"
with:
github-token: ${{ secrets.GITHUB_TOKEN }}
script: |
const output = `#### Terraform Format and Style 🖌\`${{ steps.fmt.outcome }}\`
#### Terraform Initialization ⚙️\`${{ steps.init.outcome }}\`
#### Terraform Plan 📖\`${{ steps.plan.outcome }}\`
<details><summary>Show Plan</summary>
\`\`\`${process.env.PLAN}\`\`\`
</details>
*Pusher: #${{ github.actor }}, Action: \`${{ github.event_name }}\`*`;
github.issues.createComment({
issue_number: context.issue.number,
owner: context.repo.owner,
repo: context.repo.repo,
body: output
})
A clear COPY/Paste from the docs: https://learn.hashicorp.com/tutorials/terraform/github-actions
I have tried with
actions/github-script version 5 and 6 and still the same problem, But when I copy paste the plan all is great. If I do not use the output variable and use some place holder text for the body all is working great. I can see that the step.plan.outputs.stdout is Ok if I print only that.
I will be happy to share more details if needed.

Answer 1

I also encountered a similar issue.
I seem github-script can't give to argument for too long script.
reference:
https://github.com/robburger/terraform-pr-commenter/issues/6#issuecomment-826966670
https://github.community/t/maximum-length-for-the-comment-body-in-issues-and-pr/148867
my answer:
- name: truncate terraform plan result
run: |
plan=$(cat <<'EOF'
${{ format('{0}{1}', steps.plan.outputs.stdout, steps.plan.outputs.stderr) }}
EOF
)
echo "${plan}" | grep -v 'Refreshing state' >> $GITHUB_ENV
echo "EOF" >> $GITHUB_ENV
- name: create comment from plan result
uses: actions/github-script#0.9.0
if: github.event_name == 'pull_request'
with:
github-token: ${{ secrets.GITHUB_TOKEN }}
script: |
const output = `#### Terraform Initialization ⚙️\`${{ steps.init.outcome }}\`
#### Terraform Plan 📖\`${{ steps.plan.outcome }}\`
<details><summary>Show Plan</summary>
\`\`\`\n
${ process.env.PLAN }
\`\`\`
</details>
*Pusher: #${{ github.actor }}, Action: \`${{ github.event_name }}\`, Working Directory: \`${{ inputs.TF_WORK_DIR }}\`, Workflow: \`${{ github.workflow }}\`*`;
github.issues.createComment({
issue_number: context.issue.number,
owner: context.repo.owner,
repo: context.repo.repo,
body: output
})```

Answer 2

Based on #Zambozo's hint in the comments, this worked for me great:
- name: Terraform Plan
id: plan
run: terraform plan -no-color -input=false
- name: generate random delimiter
run: echo "DELIMITER=$(uuidgen)" >> $GITHUB_ENV
- name: truncate terraform plan result
run: |
echo "PLAN<<${{ env.DELIMITER }}" >> $GITHUB_ENV
echo '[maybe truncated]' >> $GITHUB_ENV
tail --bytes=10000 <<'${{ env.DELIMITER }}' >> $GITHUB_ENV
${{ format('{0}{1}', steps.plan.outputs.stderr, steps.plan.outputs.stdout) }}
${{ env.DELIMITER }}
echo >> $GITHUB_ENV
echo "${{ env.DELIMITER }}" >> $GITHUB_ENV
- name: post plan as sticky comment
uses: marocchino/sticky-pull-request-comment#v2
with:
header: plan
message: |
#### Terraform Plan 📖\`${{ steps.plan.outcome }}\`
<details><summary>Show Plan</summary>
```
${{ env.PLAN }}
```
</details>
Notably GitHub does have an upper limit on comment size, so this only displays the last 10kB of the plan (showing the summary and warnings).
This also implements secure heredoc delimiting to avoid malicious output escaping.
Also note that the empty lines before and after the triplebacktics in the message are significant to avoid destroying the formatting.