watchtower

A simple file/directory watcher library

This is a fork of ibdknox/watchtower. The original implementation uses polling to detect changes on file system, this version uses the gmethvin/directory-watcher.

The purpose for this change is to provide much faster notifications for file changes, and consume much less CPU, especially on large projects.

The public API is the same, so this almost a drop-in replacement (see the changes below). You can just override the dependency to ibdknox/watchtower with jarppe/watchtower.

The status of this is pretty much alpha for now.

Usage

(watcher ["src/" "resources/"]
  (file-filter ignore-dotfiles) ;; add a filter for the files we care about
  (file-filter (extensions :clj :cljs)) ;; filter by extensions
  (on-change #(println "files changed: " %)))

Changes to ibdknox/watchtower

The original watchtower polls filesystem and detects changes to files based on file timestamp. This version uses gmethvin/directory-watcher.

1. The gmethvin/directory-watcher, and therefore this library, requires JDK 8
2. The ibdknox/watchtower calls callback immediately with every file in event, this library does not call the callback initially. Only the actual changes cause the callback invocation.
3. In ibdknox/watchtower the watchtower.core/watcher returned a future, this version returns a zero arity fn that will shutdown watcher when invoked.

This version also has some tests for public API and adds some annotations to avoid reflection.

Testing

This version uses clojure tools-deps instead of Leiningen, so make sure you have clojure CLI installed (on Mac's you can just brew install clojure).

clojure -A:test -m kaocha.runner

You can run tests on docker container:

docker run --rm -v ~/.m2:/root/.m2 -v $(pwd):/watchtower -w /watchtower clojure:openjdk-11-tools-deps clojure -A:test -m kaocha.runner

You can run the nrepl in docker container too, here's an example that binds nrepl to localhost:6000:

docker run --rm -v ~/.m2:/root/.m2 -v $(pwd):/watchtower -w /watchtower -p 6000:6000 clojure:openjdk-11-tools-deps clojure -R:dev:test:nrepl -m nrepl.cmdline -b 0.0.0.0 -p 6000

Instruct your favourite IDE to open an nrepl client to localhost:6000 and hack on. The tests can be run in repl by calling:

(user/run-unit-tests)

License

Copyright (C) 2011 Chris Granger

Distributed under the Eclipse Public License, the same as Clojure.