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Public preview


Public preview: This is a public preview component. Public preview components are subject to breaking changes, and may be replaced with equivalent functionality that cover the same use case.

The import.file block imports custom components from a file or a directory and exposes them to the importer. import.file blocks must be given a label that determines the namespace where custom components are exposed.

Imported directories are treated as single modules to support composability. That means that you can define a custom component in one file and use it in another custom component in another file in the same directory.


import.file "NAMESPACE" {
  filename = PATH_NAME


The following arguments are supported:

filenamestringPath of the file or directory on disk to watch.yes
detectorstringWhich file change detector to use (fsnotify, poll)."fsnotify"no
poll_frequencydurationHow often to poll for file changes."1m"no

File change detectors

File change detectors detect when the file needs to be re-read from disk. local.file supports two detectors: fsnotify and poll.


The fsnotify detector subscribes to filesystem events, which indicate when the watched file is updated. This detector requires a filesystem that supports events at the operating system level. Network-based filesystems like NFS or FUSE won’t work.

The component re-reads the watched file when a filesystem event is received. This re-read happens for any filesystem event related to the file, including a permissions change.

fsnotify also polls for changes to the file with the configured poll_frequency as a fallback.

fsnotify stops receiving filesystem events if the watched file has been deleted, renamed, or moved. The subscription is re-established on the next poll once the watched file exists again.


The poll file change detector causes the watched file to be re-read every poll_frequency, regardless of whether the file changed.


This example imports a module from a file and instantiates a custom component from the import that adds two numbers: