Action inputs can be read with `getInput` which returns a `string` or `getBooleanInput` which parses a boolean based on the [yaml 1.2 specification](https://yaml.org/spec/1.2/spec.html#id2804923). If `required` set to be false, the input should have a default value in `action.yml`.
Outputs can be set with `setOutput` which makes them available to be mapped into inputs of other actions to ensure they are decoupled.
Since each step runs in a separate process, you can use `exportVariable` to add it to this step and future steps environment blocks.
```js
core.exportVariable('envVar', 'Val');
```
#### Setting a secret
Setting a secret registers the secret with the runner to ensure it is masked in logs.
```js
core.setSecret('myPassword');
```
#### PATH Manipulation
To make a tool's path available in the path for the remainder of the job (without altering the machine or containers state), use `addPath`. The runner will prepend the path given to the jobs PATH.
```js
core.addPath('/path/to/mytool');
```
#### Exit codes
You should use this library to set the failing exit code for your action. If status is not set and the script runs to completion, that will lead to a success.
```js
const core = require('@actions/core');
try {
// Do stuff
}
catch (err) {
// setFailed logs the message and sets a failing exit code
core.setFailed(`Action failed with error ${err}`);
Note that `setNeutral` is not yet implemented in actions V2 but equivalent functionality is being planned.
#### Logging
Finally, this library provides some utilities for logging. Note that debug logging is hidden from the logs by default. This behavior can be toggled by enabling the [Step Debug Logs](../../docs/action-debugging.md#step-debug-logs).
```js
const core = require('@actions/core');
const myInput = core.getInput('input');
try {
core.debug('Inside try block');
if (!myInput) {
core.warning('myInput was not set');
}
if (core.isDebug()) {
// curl -v https://github.com
} else {
// curl https://github.com
}
// Do stuff
core.info('Output to the actions build log')
}
catch (err) {
core.error(`Error ${err}, action may still succeed though`);
}
```
This library can also wrap chunks of output in foldable groups.
Colored output is supported in the Action logs via standard [ANSI escape codes](https://en.wikipedia.org/wiki/ANSI_escape_code). 3/4 bit, 8 bit and 24 bit colors are all supported.
core.info('\u001b[35mThis foreground will be magenta')
core.info('This foreground will reset to the default')
```
Manually typing escape codes can be a little difficult, but you can use third party modules such as [ansi-styles](https://github.com/chalk/ansi-styles).