Metadata "tmpdir"

The tmpdir metadata creates a temporary directory for the duration of the action execution. The directory is decommissioned right before the action finishes its execution unless the dirty metadata is enabled.

• Type: boolean|string|function

Usage

To create a temporary directory set the value true to the metadata tmpdir property. The pathname of the created directory is available inside the action handler:

nikita
// Call an action with $tmpdir
.call({
  $tmpdir: true}, ({metadata: {tmpdir}}) => {
  // Print pathname
  console.info(tmpdir) // /var/folders/by/fbqj_yjx30xgx_4tc0fr50q80000gn/T/nikita-005a47fc-0d7d-49c2-9411-c4989e6c16f3
})

When actions are running over SSH, the temporary directory is always created inside the /tmp folder. Otherwise, it is inside the default OS temporary directory returned by the Node.js native function os.tmpdir().

The directory name is generated based on the uuid metadata. When it is created with boolean true, the directory is unique for the entire Nikita's session and shared with all the child actions. Thus, enabling the property with true in children doesn't create a new directory when it is already enabled in the parent action. The following example validate this behavior:

const assert = require('assert');
(async () => {
  await nikita
  // Call parent action with tmpdir enabled
  .call({
    $tmpdir: true  }, async function({metadata: {tmpdir}}) {
    // Save parent tmpdir
    const parentDir = tmpdir
    // Call child action with tmpdir enabled
    await this.call({
      $tmpdir: true    }, function({metadata: {tmpdir}}) {
      // Assert directories are the same
      assert.equal(parentDir, tmpdir)    })
  })
})()

String value

To provide a pathname to a directory being created, pass a string value. The pathname can be relative to the default OS temporary folder or absolute to the file system:

nikita
// Relative pathname
.call({
  $tmpdir: './a_relative_dir',}, ({metadata: {tmpdir}}) => {
  // Print pathname
  console.info(tmpdir) // /var/folders/by/fbqj_yjx30xgx_4tc0fr50q80000gn/T/a_relative_dir
})
// Absolute pathname
.call({
  $tmpdir: '/tmp/an_absolute_dir',}, ({metadata: {tmpdir}}) => {
  // Print pathname
  console.info(tmpdir) // /tmp/an_absolute_dir
})

Function value

To provide a custom logic on creating a directory pathname, associate a function to the tmpdir metadata that returns the pathname. It receives an object as the first argument with the following properties:

• action
  Current action object
• os_tmpdir
  Default OS temporary folder
• tmpdir
  Generated directory name basing on the uuid metadata.

The following example demonstrates creating a directory basing on a configuration property:

nikita
// Relative pathname
.call({
  user: 'leon',
  $tmpdir: ({action, os_tmpdir, tmpdir}) => `/tmp/${action.config.user}`}, ({metadata: {tmpdir}}) => {
  // Print pathname
  console.info(tmpdir) // /tmp/leon
})