Use new idempotent API for mazerunner command fetch

features/fixtures/ios/Fixture/CommandReaderThread.swift

@@ -12,6 +12,7 @@ import os
 class CommandReaderThread: Thread {
     var fixtureConfig: FixtureConfig
     var commandReceiver: CommandReceiver
+    var lastCommandID: String = ""
 
     init(fixtureConfig: FixtureConfig, commandReceiver: CommandReceiver) {
         self.fixtureConfig = fixtureConfig
@@ -29,29 +30,53 @@ class CommandReaderThread: Thread {
         }
     }
 
-    func receiveNextCommand() {
-        let fetchTask = CommandFetchTask(url: fixtureConfig.commandURL)
+    func newStartedFetchTask() -> CommandFetchTask {
+        let fetchTask = CommandFetchTask(url: fixtureConfig.commandURL, afterCommandID: lastCommandID)
         fetchTask.start()
+        return fetchTask
+    }
+
+    func receiveNextCommand() {
+        let maxWaitTime = 5.0
+        let pollingInterval = 1.0
+
+        var fetchTask = newStartedFetchTask()
+        let startTime = Date()
 
         while true {
+            Thread.sleep(forTimeInterval: pollingInterval)
             switch fetchTask.state {
             case CommandFetchState.success:
-                commandReceiver.receiveCommand(command: fetchTask.command!)
+                logDebug("Command fetch: Request succeeded")
+                let command = fetchTask.command!
+                lastCommandID = command.uuid
+                commandReceiver.receiveCommand(command: command)
                 return
             case CommandFetchState.fetching:
-                logDebug("Command fetch server hasn't responded yet, waiting 1 second more...")
-                Thread.sleep(forTimeInterval: 1)
+                let duration = Date() - startTime
+                if duration < maxWaitTime {
+                    logDebug("Command fetch: Server hasn't responded in \(duration)s (max \(maxWaitTime)). Waiting \(pollingInterval)s more...")
+                } else {
+                    fetchTask.cancel()
+                    logInfo("Command fetch: Server hasn't responded in \(duration)s (max \(maxWaitTime)). Trying again...")
+                    fetchTask = newStartedFetchTask()
+                }
                 break
             case CommandFetchState.failed:
-                logInfo("Command fetch request failed. Trying again...")
-                Thread.sleep(forTimeInterval: 1)
-                fetchTask.start()
+                logInfo("Command fetch: Request failed. Trying again...")
+                fetchTask = newStartedFetchTask()
                 break
             }
         }
     }
 }
 
+extension Date {
+    static func - (lhs: Date, rhs: Date) -> TimeInterval {
+        return lhs.timeIntervalSinceReferenceDate - rhs.timeIntervalSinceReferenceDate
+    }
+}
+
 enum CommandFetchState {
     case failed, fetching, success
 }
@@ -60,16 +85,21 @@ class CommandFetchTask {
     var url: URL
     var state = CommandFetchState.failed
     var command: MazeRunnerCommand?
+    var task: URLSessionTask?
+
+    init(url: URL, afterCommandID: String) {
+        self.url = URL(string: "\(url.absoluteString)?after=\(afterCommandID)")!
+    }
 
-    init(url: URL) {
-        self.url = url
+    func cancel() {
+        task?.cancel()
     }
 
     func start() {
         logInfo("Fetching next command from \(url)")
         state = CommandFetchState.fetching
         let request = URLRequest(url: url)
-        let task = URLSession.shared.dataTask(with: request) { data, response, error in
+        task = URLSession.shared.dataTask(with: request) { data, response, error in
             if let data = data {
                 let decoder = JSONDecoder()
                 decoder.keyDecodingStrategy = .convertFromSnakeCase
@@ -88,6 +118,6 @@ class CommandFetchTask {
                 logError("Failed to fetch command: HTTP Request to \(String(describing: self.url)) failed: \(error)")
             }
         }
-        task.resume()
+        task?.resume()
     }
 }

features/fixtures/ios/Fixture/MazeRunnerCommand.swift

@@ -10,16 +10,19 @@ import Foundation
 class MazeRunnerCommand: Codable {
     let message: String
     let action: String
+    let uuid: String
     let args: Array<String>
 
-    init(action: String, args: Array<String>, message: String) {
+    init(uuid: String, action: String, args: Array<String>, message: String) {
+        self.uuid = uuid
         self.message = message
         self.action = action
         self.args = args
     }
 
     required init(from decoder: Decoder) throws {
         let container = try decoder.container(keyedBy: CodingKeys.self)
+        self.uuid = try container.decodeIfPresent(String.self, forKey: .uuid) ?? ""
         self.message = try container.decodeIfPresent(String.self, forKey: .message) ?? ""
         self.action = try container.decodeIfPresent(String.self, forKey: .action) ?? ""
         self.args = try container.decodeIfPresent(Array<String>.self, forKey: .args) ?? []

features/fixtures/ios/Scenarios/Scenario.swift

@@ -57,14 +57,17 @@ class Scenario: NSObject {
     }
 
     func isMazeRunnerAdministrationURL(url: URL) -> Bool {
-        switch url {
-        case fixtureConfig.tracesURL, fixtureConfig.commandURL, fixtureConfig.metricsURL:
+        if url.absoluteString.hasPrefix(fixtureConfig.tracesURL.absoluteString) ||
+            url.absoluteString.hasPrefix(fixtureConfig.commandURL.absoluteString) ||
+            url.absoluteString.hasPrefix(fixtureConfig.metricsURL.absoluteString) {
             return true
-        case fixtureConfig.reflectURL:
+        }
+
+        if url.absoluteString.hasPrefix(fixtureConfig.reflectURL.absoluteString) {
             return false // reflectURL is fair game!
-        default:
-            return false
         }
+
+        return false
     }
 
     func reportMeasurements() {