From 2e1c1fd3c8deecb0105c44507b1c12e19abd046a Mon Sep 17 00:00:00 2001
From: Hornwitser <github@hornwitser.no>
Date: Sun, 27 Mar 2022 20:19:52 +0200
Subject: [PATCH] Remove duplicated instance check

Deduplicate instance existence check for requests in master.
---
 packages/master/src/ControlConnection.js | 34 +++++-------------------
 packages/master/src/Master.js            | 21 +++++++++++----
 2 files changed, 22 insertions(+), 33 deletions(-)

diff --git a/packages/master/src/ControlConnection.js b/packages/master/src/ControlConnection.js
index 068076ee..5a10a780 100644
--- a/packages/master/src/ControlConnection.js
+++ b/packages/master/src/ControlConnection.js
@@ -159,10 +159,7 @@ class ControlConnection extends BaseConnection {
 
 	async getInstanceRequestHandler(message) {
 		let id = message.data.id;
-		let instance = this._master.instances.get(id);
-		if (!instance) {
-			throw new libErrors.RequestError(`Instance with ID ${id} does not exist`);
-		}
+		let instance = this._master.getRequestInstance(id);
 
 		return {
 			id,
@@ -249,11 +246,7 @@ class ControlConnection extends BaseConnection {
 	}
 
 	async deleteInstanceRequestHandler(message, request) {
-		let instance = this._master.instances.get(message.data.instance_id);
-		if (!instance) {
-			throw new libErrors.RequestError(`Instance with ID ${message.data.instance_id} does not exist`);
-		}
-
+		let instance = this._master.getRequestInstance(message.data.instance_id);
 		if (instance.config.get("instance.assigned_slave") !== null) {
 			await this.forwardRequestToInstance(message, request);
 		}
@@ -266,11 +259,7 @@ class ControlConnection extends BaseConnection {
 	}
 
 	async getInstanceConfigRequestHandler(message) {
-		let instance = this._master.instances.get(message.data.instance_id);
-		if (!instance) {
-			throw new libErrors.RequestError(`Instance with ID ${message.data.instance_id} does not exist`);
-		}
-
+		let instance = this._master.getRequestInstance(message.data.instance_id);
 		return {
 			serialized_config: instance.config.serialize("control"),
 		};
@@ -290,11 +279,7 @@ class ControlConnection extends BaseConnection {
 	}
 
 	async setInstanceConfigFieldRequestHandler(message) {
-		let instance = this._master.instances.get(message.data.instance_id);
-		if (!instance) {
-			throw new libErrors.RequestError(`Instance with ID ${message.data.instance_id} does not exist`);
-		}
-
+		let instance = this._master.getRequestInstance(message.data.instance_id);
 		if (message.data.field === "instance.assigned_slave") {
 			throw new libErrors.RequestError("instance.assigned_slave must be set through the assign-slave interface");
 		}
@@ -309,11 +294,7 @@ class ControlConnection extends BaseConnection {
 	}
 
 	async setInstanceConfigPropRequestHandler(message) {
-		let instance = this._master.instances.get(message.data.instance_id);
-		if (!instance) {
-			throw new libErrors.RequestError(`Instance with ID ${message.data.instance_id} does not exist`);
-		}
-
+		let instance = this._master.getRequestInstance(message.data.instance_id);
 		let { field, prop, value } = message.data;
 		instance.config.setProp(field, prop, value, "control");
 		await this.updateInstanceConfig(instance);
@@ -321,10 +302,7 @@ class ControlConnection extends BaseConnection {
 
 	async assignInstanceCommandRequestHandler(message, request) {
 		let { slave_id, instance_id } = message.data;
-		let instance = this._master.instances.get(instance_id);
-		if (!instance) {
-			throw new libErrors.RequestError(`Instance with ID ${instance_id} does not exist`);
-		}
+		let instance = this._master.getRequestInstance(instance_id);
 
 		// Check if target slave is connected
 		let newSlaveConnection;
diff --git a/packages/master/src/Master.js b/packages/master/src/Master.js
index 3d83e849..863bf48a 100644
--- a/packages/master/src/Master.js
+++ b/packages/master/src/Master.js
@@ -424,6 +424,21 @@ class Master {
 		}
 	}
 
+	/**
+	 * Get instance by ID for a request
+	 *
+	 * @param {number} instanceId - ID of instance to get.
+	 * @returns {object} instance
+	 * @throws {module:lib/errors.RequestError} if the instance does not exist.
+	 */
+	getRequestInstance(instanceId) {
+		let instance = this.instances.get(instanceId);
+		if (!instance) {
+			throw new libErrors.RequestError(`Instance with ID ${instanceId} does not exist`);
+		}
+		return instance;
+	}
+
 	addInstanceHooks(instance) {
 		instance.config.on("fieldChanged", (group, field, prev) => {
 			if (group.name === "instance" && field === "name") {
@@ -608,11 +623,7 @@ class Master {
 	 * @returns {object} data returned from the request.
 	 */
 	async forwardRequestToInstance(request, data) {
-		let instance = this.instances.get(data.instance_id);
-		if (!instance) {
-			throw new libErrors.RequestError(`Instance with ID ${data.instance_id} does not exist`);
-		}
-
+		let instance = this.getRequestInstance(data.instance_id);
 		let slaveId = instance.config.get("instance.assigned_slave");
 		if (slaveId === null) {
 			throw new libErrors.RequestError("Instance is not assigned to a slave");