Current File : //home2/vacivi36/ava/.grunt/tasks/watch.js
/**
* This is a wrapper task to handle the grunt watch command. It attempts to use
* Watchman to monitor for file changes, if it's installed, because it's much faster.
*
* If Watchman isn't installed then it falls back to the grunt-contrib-watch file
* watcher for backwards compatibility.
*/
/* eslint-env node */
module.exports = grunt => {
/**
* This is a wrapper task to handle the grunt watch command. It attempts to use
* Watchman to monitor for file changes, if it's installed, because it's much faster.
*
* If Watchman isn't installed then it falls back to the grunt-contrib-watch file
* watcher for backwards compatibility.
*/
const watchHandler = function() {
const async = require('async');
const watchTaskDone = this.async();
let watchInitialised = false;
let watchTaskQueue = {};
let processingQueue = false;
const watchman = require('fb-watchman');
const watchmanClient = new watchman.Client();
// Grab the tasks and files that have been queued up and execute them.
var processWatchTaskQueue = function() {
if (!Object.keys(watchTaskQueue).length || processingQueue) {
// If there is nothing in the queue or we're already processing then wait.
return;
}
processingQueue = true;
// Grab all tasks currently in the queue.
var queueToProcess = watchTaskQueue;
// Reset the queue.
watchTaskQueue = {};
async.forEachSeries(
Object.keys(queueToProcess),
function(task, next) {
var files = queueToProcess[task];
var filesOption = '--files=' + files.join(',');
grunt.log.ok('Running task ' + task + ' for files ' + filesOption);
// Spawn the task in a child process so that it doesn't kill this one
// if it failed.
grunt.util.spawn(
{
// Spawn with the grunt bin.
grunt: true,
// Run from current working dir and inherit stdio from process.
opts: {
cwd: grunt.moodleEnv.fullRunDir,
stdio: 'inherit'
},
args: [task, filesOption]
},
function(err, res, code) {
if (code !== 0) {
// The grunt task failed.
grunt.log.error(err);
}
// Move on to the next task.
next();
}
);
},
function() {
// No longer processing.
processingQueue = false;
// Once all of the tasks are done then recurse just in case more tasks
// were queued while we were processing.
processWatchTaskQueue();
}
);
};
const originalWatchConfig = grunt.config.get(['watch']);
const watchConfig = Object.keys(originalWatchConfig).reduce(function(carry, key) {
if (key == 'options') {
return carry;
}
const value = originalWatchConfig[key];
const taskNames = value.tasks;
const files = value.files;
let excludes = [];
if (value.excludes) {
excludes = value.excludes;
}
taskNames.forEach(function(taskName) {
carry[taskName] = {
files,
excludes,
};
});
return carry;
}, {});
watchmanClient.on('error', function(error) {
// We have to add an error handler here and parse the error string because the
// example way from the docs to check if Watchman is installed doesn't actually work!!
// See: https://github.com/facebook/watchman/issues/509
if (error.message.match('Watchman was not found')) {
// If watchman isn't installed then we should fallback to the other watch task.
grunt.log.ok('It is recommended that you install Watchman for better performance using the "watch" command.');
// Fallback to the old grunt-contrib-watch task.
grunt.renameTask('watch-grunt', 'watch');
grunt.task.run(['watch']);
// This task is finished.
watchTaskDone(0);
} else {
grunt.log.error(error);
// Fatal error.
watchTaskDone(1);
}
});
watchmanClient.on('subscription', function(resp) {
if (resp.subscription !== 'grunt-watch') {
return;
}
resp.files.forEach(function(file) {
grunt.log.ok('File changed: ' + file.name);
var fullPath = grunt.moodleEnv.fullRunDir + '/' + file.name;
Object.keys(watchConfig).forEach(function(task) {
const fileGlobs = watchConfig[task].files;
var match = fileGlobs.some(function(fileGlob) {
return grunt.file.isMatch(`**/${fileGlob}`, fullPath);
});
if (match) {
// If we are watching a subdirectory then the file.name will be relative
// to that directory. However the grunt tasks expect the file paths to be
// relative to the Gruntfile.js location so let's normalise them before
// adding them to the queue.
var relativePath = fullPath.replace(grunt.moodleEnv.gruntFilePath + '/', '');
if (task in watchTaskQueue) {
if (!watchTaskQueue[task].includes(relativePath)) {
watchTaskQueue[task] = watchTaskQueue[task].concat(relativePath);
}
} else {
watchTaskQueue[task] = [relativePath];
}
}
});
});
processWatchTaskQueue();
});
process.on('SIGINT', function() {
// Let the user know that they may need to manually stop the Watchman daemon if they
// no longer want it running.
if (watchInitialised) {
grunt.log.ok('The Watchman daemon may still be running and may need to be stopped manually.');
}
process.exit();
});
// Initiate the watch on the current directory.
watchmanClient.command(['watch-project', grunt.moodleEnv.fullRunDir], function(watchError, watchResponse) {
if (watchError) {
grunt.log.error('Error initiating watch:', watchError);
watchTaskDone(1);
return;
}
if ('warning' in watchResponse) {
grunt.log.error('warning: ', watchResponse.warning);
}
var watch = watchResponse.watch;
var relativePath = watchResponse.relative_path;
watchInitialised = true;
watchmanClient.command(['clock', watch], function(clockError, clockResponse) {
if (clockError) {
grunt.log.error('Failed to query clock:', clockError);
watchTaskDone(1);
return;
}
// Generate the expression query used by watchman.
// Documentation is limited, but see https://facebook.github.io/watchman/docs/expr/allof.html for examples.
// We generate an expression to match any value in the files list of all of our tasks, but excluding
// all value in the excludes list of that task.
//
// [anyof, [
// [allof, [
// [anyof, [
// ['match', validPath, 'wholename'],
// ['match', validPath, 'wholename'],
// ],
// [not,
// [anyof, [
// ['match', invalidPath, 'wholename'],
// ['match', invalidPath, 'wholename'],
// ],
// ],
// ],
var matchWholeName = fileGlob => ['match', fileGlob, 'wholename'];
var matches = Object.keys(watchConfig).map(function(task) {
const matchAll = [];
matchAll.push(['anyof'].concat(watchConfig[task].files.map(matchWholeName)));
if (watchConfig[task].excludes.length) {
matchAll.push(['not', ['anyof'].concat(watchConfig[task].excludes.map(matchWholeName))]);
}
return ['allof'].concat(matchAll);
});
matches = ['anyof'].concat(matches);
var sub = {
expression: matches,
// Which fields we're interested in.
fields: ["name", "size", "type"],
// Add our time constraint.
since: clockResponse.clock
};
if (relativePath) {
/* eslint-disable camelcase */
sub.relative_root = relativePath;
}
watchmanClient.command(['subscribe', watch, 'grunt-watch', sub], function(subscribeError) {
if (subscribeError) {
// Probably an error in the subscription criteria.
grunt.log.error('failed to subscribe: ', subscribeError);
watchTaskDone(1);
return;
}
grunt.log.ok('Listening for changes to files in ' + grunt.moodleEnv.fullRunDir);
});
});
});
};
// Rename the grunt-contrib-watch "watch" task because we're going to wrap it.
grunt.renameTask('watch', 'watch-grunt');
// Register the new watch handler.
grunt.registerTask('watch', 'Run tasks on file changes', watchHandler);
grunt.config.merge({
watch: {
options: {
nospawn: true // We need not to spawn so config can be changed dynamically.
},
},
});
return watchHandler;
};
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