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See [here](https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/) for more explanations: > We are monitoring telemetry for the usage of these commands and plan to fully disable them on 31st May 2023. Starting 1st June 2023 workflows using save-state or set-output commands via stdout will fail with an error.
49 lines
1.5 KiB
Markdown
49 lines
1.5 KiB
Markdown
# Capture An Output Value For Use In A Later Step
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GitHub Actions has a workflow command called `set-output`. This can be used to
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capture the output from a shell command in step. That output value can then be
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used in a later step.
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A useful example of this is reading the version of a tool from a dot-file to
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tell a later step what version of that tool to install.
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Here's the `.tool-versions` file included in my repository:
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```
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postgres 13.1
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ruby 3.0.0
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nodejs 15.4.0
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```
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Assuming I've already [checked out my
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repo](https://github.com/actions/checkout), I can find and read the `nodejs`
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version from my `.tool-versions` file with a step that uses `set-output`.
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```yaml
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- name: Read Node.js version to install from `.tool-versions`
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id: nodejs
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run: >-
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echo "NODE_VERSION=$(
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cat .tool-versions |
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grep nodejs |
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sed 's/nodejs \(.*\)$/\1/'
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)" >> $GITHUB_OUTPUT
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```
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`echo` runs the command in the string which sets `NODE_VERSION` as an output
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value to what ends up being `15.4.0`.
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This output value can be referenced in a later step.
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```yaml
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- name: Install required Node.js version
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uses: actions/setup-node@v1
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with:
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node-version: "${{ steps.nodejs.outputs.NODE_VERSION }}"
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```
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`steps` has a reference to the `nodejs` step (note the `id` above) which then
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has `outputs` like the `NODE_VERSION`.
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[source](https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#setting-an-output-parameter)
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