Tmp dir naming

[joliss]

/cc @rwjblue, @stefanpenner, @caitp

When tmp dir handling is centralized, what do we want the names of the temporary directories to be?

Currently we have names like babel-tmp_dest_dir-kbIdaoyR.tmp, which isn't terribly user-friendly.

Are we going to do something like this (numbered by order of execution), or should we try to put more information into the names?

01-babel
02-babel
03-babel
04-babel
05-sass
06-sass
07-funnel
08-jshint
09-merge-trees
10-merge-trees
11-merge-trees

If we wanted to put more information (like 01-babel-lib, 02-babel-vendor), it would likely have to be supplied by the build definition (like Brocfile.js or ember-app.js). I have no idea whether this is doable in practice. But if we plan on doing this, I'd like to take it into account for the API.

Semi-relatedly, currently everything is in ./tmp, but we likely want to change this. I'm thinking maybe /tmp/broccoli.$PID/trees/01-babel for the output directory of the first plugin, and /tmp/broccoli.$PID/caches/01-babel for its cache directory. Alternatively, we could use /tmp/broccoli.$PID/01-babel/{out,cache}, and create symlinks at /tmp/broccoli.$PID/01-babel/in-{0,1,2,3,4,5} pointing to the input directories; those symlinks would not be used by Broccoli, but created for the convenience of people inspecting the tmp dirs.

[caitp]

Ordering the temp directories by use order would work well for us. We don't care a whole lot about tracking the pid as we clean the temp dir when killing gulp. Just naming the temp dirs something more informative would be a bit nicer. @IgorMinar has more insight into the angular use case, so cc-ing him

[cecchi]

Somewhat related: Should we consider a different name for the temporary directory itself? I could imagine a case where a project has an existing tmp/ directory. Would renaming to .broc/ or .broccoli/ make sense?

[joliss]

@cecchi, yes, unless there are unforeseen issues with this, we'll likely use the system /tmp dir when available (and it would be configurable as well).

[stefanpenner]

• these names seem much more friendly.
• we should work hard to make tmp dir configurable

[stefanpenner]

broccoli 1.x has this

broccoli/lib/builder.js

Lines 272 to 292 in 0bc034c

	// Create temporary directory, like
	// /tmp/broccoli-9rLfJh/out-067-merge_trees_vendor_packages
	// type is 'out' or 'cache'
	mkTmpDir(nodeWrapper, type) {
	let nameAndAnnotation =
	nodeWrapper.nodeInfo.name + ' ' + (nodeWrapper.nodeInfo.annotation || '');
	// slugify turns fooBar into foobar, so we call underscored first to
	// preserve word boundaries
	let suffix = underscoreString.underscored(nameAndAnnotation.substr(0, 60));
	suffix = underscoreString.slugify(suffix).replace(/-/g, '_');
	// 1 .. 147 -> '001' .. '147'
	const paddedId = underscoreString.pad(
	'' + nodeWrapper.id,
	('' + this.nodeWrappers.length).length,
	'0'
	);
	const dirname = type + '-' + paddedId + '-' + suffix;
	const tmpDir = path.join(this.builderTmpDir, dirname);
	fs.mkdirSync(tmpDir);
	return tmpDir;
	}