jobd: add set-target-concurrency request

README.md

@@ -67,6 +67,9 @@ for target is not enough for you, change it to fit your needs.
 * **`run-manual(ids: int[])`** — enqueue and run jobs with specified IDs and
   `status` set to `manual`, and return results.
 
+* **`set-target-concurrency(target: string, concurrency: int)`** — set concurrency
+  of target `target`.
+
 ### jobd-master requests
 
 * **`register-worker(targets: string[])`** — used by a jobd instance to register

src/jobd.js

@@ -5,7 +5,7 @@ const config = require('./lib/config')
 const db = require('./lib/db')
 const {uniq} = require('lodash')
 const {createCallablePromise} = require('./lib/util')
-const {validateTargetsListFormat} = require('./lib/data-validator')
+const {validateObjectSchema, validateTargetsListFormat} = require('./lib/data-validator')
 const RequestHandler = require('./lib/request-handler')
 const {
     Server,
@@ -136,6 +136,7 @@ function initRequestHandler() {
     requestHandler.set('run-manual', onRunManual)
     requestHandler.set('pause', onPause)
     requestHandler.set('continue', onContinue)
+    requestHandler.set('set-target-concurrency', onSetTargetConcurrency)
 }
 
 function initServer() {
@@ -324,6 +325,33 @@ function onContinue(data, requestNo, connection) {
     )
 }
 
+/**
+ * @param {object} data
+ * @param {number} requestNo
+ * @param {Connection} connection
+ */
+function onSetTargetConcurrency(data, requestNo, connection) {
+    try {
+        validateObjectSchema(data, [
+            // name         // type  // required
+            ['concurrency', 'i',     true],
+            ['target',      's',     true],
+        ])
+    } catch (e) {
+        connection.send(
+            new ResponseMessage(requestNo)
+                .setError(e.message)
+        )
+        return
+    }
+
+    worker.setTargetConcurrency(data.target, data.concurrency)
+    connection.send(
+        new ResponseMessage(requestNo)
+            .setData('ok')
+    )
+}
+
 /**
  * @private
  * @param data

src/lib/worker.js

@@ -72,6 +72,17 @@ class Worker extends EventEmitter {
         }
     }
 
+    /**
+     * @param {string} target
+     * @param {number} concurrency
+     */
+    setTargetConcurrency(target, concurrency) {
+        if (!(target in this.targets))
+            throw new Error(`target '${target}' not found`)
+
+        this.targets[target].queue.concurrency = concurrency
+    }
+
     /**
      * Stop queues associated with specified targets.
      *