Determining if Gulp task called from another task - gulp

Question

Is there a way to find out if a task been invoked directly or from another task?
runSequence = require 'run-sequence'
gulp.task 'build', ->
....
gulp.task 'run', ->
runSequence 'build', -> gulp.start('server')
I need an if case in build task that says:
if it was called directly - (gulp build) then do something;
or if it was invoked from run task then do something else

Answer 1

This might be an X/Y problem. What are you actually trying to accomplish?
But to answer the question; I think the only way is to look at the call stack trace and make sure only Gulp touches the task. I wrote a function that finds who orchestrated the task. You can just put the function inline with your gulpfile.js and use it like boolean.
The following code relies on npm parse-stack so make sure to npm install parse-stack
Usage: if(wasGulpTaskCalledDirectly()) { /*...*/ }
function wasGulpTaskCalledDirectly()
{
var parseStack = require("parse-stack");
var stack = parseStack(new Error());
// Find the index in the call stack where the task was started
var stackTaskStartIndex = -1;
for(var i = 0; i < stack.length; i++)
{
if(stack[i].name == 'Gulp.Orchestrator.start')
{
stackTaskStartIndex = i;
break;
}
}
// Once we find where the orchestrator started the task
// Find who called the orchestrator (one level up)
var taskStarterIndex = stackTaskStartIndex+1;
var isValidIndex = taskStarterIndex > 0 && taskStarterIndex < stack.length;
if(isValidIndex && /gulp\.js$/.test((stack[taskStarterIndex].filepath || "")))
{
return true;
}
return false;
}
You can find my full gulpfile.js used for testing below:
// This is a test for this SE question: http://stackoverflow.com/q/25928170/796832
// Figure out how to detect `gulp` vs `gulp build`
// Include gulp
var gulp = require('gulp');
var runSequence = require('run-sequence');
// Add this in from the above code block in the answer
//function wasGulpTaskCalledDirectly()
// ...
gulp.task('build', function() {
//console.log(wasGulpTaskCalledDirectly());
if(wasGulpTaskCalledDirectly())
{
// Do stuff here
}
else
{
// Do other stuff here
}
return gulp.src('./index.html', {base: './'})
.pipe(gulp.dest('./dist'));
});
// This does nothing
gulp.task('start-server', function() {
return gulp.src('./index.html', {base: './'});
});
// Default Task
gulp.task('default', function(callback) {
runSequence('build',
['start-server'],
callback
);
});