Support compound tasks

[elaihau]

Description

VS Code supports having tasks that are dependent on other tasks.

See https://code.visualstudio.com/docs/editor/tasks#_compound-tasks for details

[akosyakov]

@elaihau @RomanNikitenko if you can find a moment to write down how it can be done it would helpful. @idoprz would like to have a look into it

[elaihau]

All tasks can be retrieved from the task-service.ts.

Configured tasks can be retrieved from task-configurations.ts, and detected tasks from provided-task-configurations.ts.

Take this compound task for example:

        {
            "label": "Build",
            "dependsOn": ["Client Build", "Server Build"]
        }

with all the task data in memory, I believe we are able to find Client Build task and Server Build task, and start them sequentially.

In current theia, we open a separate terminal window for each and every task. In my opinion, the difficult part of this feature is figuring out a good way to use ONE terminal for all the smaller tasks.

[idoprz]

task-service.ts and task-configurations.ts are both in the browser.
Looking at the code it seems that the correct place to run tasks are from task-server, which is in the node part.

Regarding the behavior you suggested, VSCode runs each dependent task on a new terminal.

[elaihau]

task-service.ts and task-configurations.ts are both in the browser.
Looking at the code it seems that the correct place to run tasks are from task-server, which is in the node part.

yep, that's how things work in theia. we just resolve the task config in browser and pass it to the node part.

Regarding the behavior you suggested, VSCode runs each dependent task on a new terminal.

running each dependent task in a new terminal sounds good. sorry for the misleading comment.

[idoprz]

task-service.ts and task-configurations.ts are both in the browser.
Looking at the code it seems that the correct place to run tasks are from task-server, which is in the node part.

yep, that's how things work in theia. we just resolve the task config in browser and pass it to the node part.

The dependencies can create a DAG, which should be converted to a tree. Do you suggest I will read all tasks in the browser and create the tree by adding to TaskCustomization interface:
dependentTasks: TaskCustomization[];

Regarding the behavior you suggested, VSCode runs each dependent task on a new terminal.

running each dependent task in a new terminal sounds good. sorry for the misleading comment.

[elaihau]

The dependencies can create a DAG, which should be converted to a tree. Do you suggest I will read all tasks in the browser and create the tree by adding to TaskCustomization interface:
dependentTasks: TaskCustomization[];

i have no issues with that :)

[ShimonBenYair]

@akosyakov @elaihau
I am taking this issue and trying to implement it.
I will send a PR in few days

[akosyakov]

@ShimonBenYair ok, please don't forget to follow PR checklist

[ShimonBenYair]

@elaihau @akosyakov

I want the "dependsOn" array, to be of type : string (the tasks labels) and also of type TaskIdentifier (like in VSCode) :

 taskIdentifier: IJSONSchema = {
    type: 'object',
    additionalProperties: true,
    properties: {
        type: {
            type: 'string',
            description: 'The task identifier.' }
          }
    };

But if the user will not write (in the dependsOn object) all the task required properties (every type has different required properties e.g. npm, gulp …), then how will I identify the task that is related to what is mention in the taskIdentifier ?
Foe example: the required properties of "npm" are : 'type' and 'script', and the user mentioned only 'type' and 'label' ? (or just 'type')

{
    "tasks": [
      {
         "label": "shimontask1",
         "type": "shell",
         "command": "sleep 5s &&& echo something",
         "dependsOn": ["task2",  {"type": "npm","label":"task1"}  ],
         "dependsOrder": "sequence"
      },
      {
   "label": "task1",
         "type": "npm",
         "script": "test1"
      },
      {
   "label": "task1",
         "type": "npm",
         "script": "test2"
      },
      {
   "label": "task2",
         "type": "npm",
         "script": "test44"
      }
}

[elaihau]

But if the user will not write (in the dependsOn object) all the task required properties (every type has different required properties e.g. npm, gulp …), then how will I identify the task that is related to what is mention in the taskIdentifier ?

The first thing I would try, is passing "taskIdentifier" (e.g., {"type": "npm","label": "task1"}) into TaskDefinitionRegistry.getDefinition(), to see what the function returns.

if the function returns undefined, the "taskIdentifier" does not have enough information. In this case I guess we should notify the user the error.

if the function returns something other than undefined, I would check each and every task config to find the one that matches the "taskIdentifier". If there are more than one matches we could either notify the user to ask for more specific info, or simply run the first matched task. You can try it in vs code and see what it does.

[akosyakov]

Please also make sure that all user facing JSON interfaces (i.e. used to parse data) are have the same shape as in VS Code. For it, please don't guess, but read VS Code codebase.

[ShimonBenYair]

@elaihau @akosyakov

Ok, thanks.
In addition, if i have a task in the "dependsOn" array that for example runs tomcat ( so it is running in the background and doesn't seems to have exit code ) , then what should be the behavior of the parent task ? (it will never start)

{
    "tasks": [
      {
         "label": "task1",
         "type": "shell",
         "command": "echo something",
         "dependsOn": ["task2" ],
         "dependsOrder": "sequence or parallel"
      },
      {
   "label": "task2",
         "type": "shell",
         "command": "run tomcat"
      }
}

How can i solve it ?

[elaihau]

@elaihau @akosyakov

Ok, thanks.
In addition, if i have a task in the "dependsOn" array that for example runs tomcat ( so it is running in the background and doesn't seems to have exit code ) , then what should be the behavior of the parent task ? (it will never start)

{
    "tasks": [
      {
         "label": "task1",
         "type": "shell",
         "command": "echo something",
         "dependsOn": ["task2" ],
         "dependsOrder": "sequence or parallel"
      },
      {
   "label": "task2",
         "type": "shell",
         "command": "run tomcat"
      }
}

How can i solve it ?

i am not sure. i would check what vs code does in this case.

at this moment, the property "background" is not supported in Theia. So i am a little skeptical on the feasiblity of running your task1 and task2 in parallell, because Theia does not know if task2 is a background task.

-------------- UPDATE ----------------------

This is what I found from the vscode documentation: https://code.visualstudio.com/docs/editor/tasks

If you specify "dependsOrder": "sequence" then your task dependencies are executed in the order > they are listed in dependsOn. Any background/watch tasks used in dependsOn with
"dependsOrder": "sequence" must have a problem matcher that tracks when they are "done". The > following task runs task Two, task Three, and then task One.

So I guess the trick is defining a problem matcher and pattern, so that Theia knows if the task2 has "ended". (It is your definition of "ended". The task does not have to terminate)