DemoBench: open web page automatically once web server has started.

tools/demobench/src/main/kotlin/net/corda/demobench/views/NodeTerminalView.kt

@@ -1,6 +1,5 @@
 package net.corda.demobench.views
 
-import com.google.common.util.concurrent.RateLimiter
 import com.jediterm.terminal.TerminalColor
 import com.jediterm.terminal.TextStyle
 import com.jediterm.terminal.ui.settings.DefaultSettingsProvider
@@ -13,6 +12,8 @@ import javafx.scene.layout.StackPane
 import javafx.scene.layout.VBox
 import javafx.util.Duration
 import net.corda.client.rpc.notUsed
+import net.corda.core.success
+import net.corda.core.then
 import net.corda.demobench.explorer.ExplorerController
 import net.corda.demobench.model.NodeConfig
 import net.corda.demobench.model.NodeController
@@ -24,12 +25,9 @@ import net.corda.demobench.web.DBViewer
 import net.corda.demobench.web.WebServerController
 import tornadofx.*
 import java.awt.Dimension
-import java.io.IOException
-import java.net.SocketException
-import java.net.URL
+import java.net.URI
 import java.util.logging.Level
 import javax.swing.SwingUtilities
-import kotlin.concurrent.thread
 
 class NodeTerminalView : Fragment() {
     override val root by fxml<VBox>()
@@ -131,6 +129,8 @@ class NodeTerminalView : Fragment() {
         }
     }
 
+    private var webURL: URI? = null
+
     /*
      * We only want to run one web server for each node.
      * So disable the "launch" button when we have
@@ -139,32 +139,20 @@ class NodeTerminalView : Fragment() {
      */
     fun configureWebButton(config: NodeConfig) {
         launchWebButton.setOnAction {
+            if (webURL != null) {
+                app.hostServices.showDocument(webURL.toString())
+                return@setOnAction
+            }
             launchWebButton.isDisable = true
 
-            webServer.open(config, onExit = {
-                launchWebButton.isDisable = false
-            })
-
-            openBrowserWhenWebServerHasStarted(config)
-        }
-    }
-
-    private fun openBrowserWhenWebServerHasStarted(config: NodeConfig) {
-        thread {
-            log.info("Waiting for web server to start ...")
-            val url = URL("http://localhost:${config.webPort}/")
-            val rateLimiter = RateLimiter.create(1.0)
-            while (true) {
-                try {
-                    rateLimiter.acquire()
-                    val conn = url.openConnection()
-                    conn.connectTimeout = 1000  // msec
-                    conn.connect()
-                    log.info("Web server started")
-                    app.hostServices.showDocument(url.toString())
-                    break
-                } catch(e: SocketException) {
-                } catch(e: IOException) {
+            log.info("Starting web server for ${config.legalName}")
+            webServer.open(config) then {
+                Platform.runLater { launchWebButton.isDisable = false }
+            } success {
+                log.info("Web server for ${config.legalName} started on $it")
+                Platform.runLater {
+                    webURL = it
+                    app.hostServices.showDocument(it.toString())
                 }
             }
         }

tools/demobench/src/main/kotlin/net/corda/demobench/web/WebServer.kt

@@ -1,10 +1,21 @@
 package net.corda.demobench.web
 
+import com.google.common.util.concurrent.ListenableFuture
+import com.google.common.util.concurrent.RateLimiter
+import com.google.common.util.concurrent.SettableFuture
+import net.corda.core.catch
+import net.corda.core.minutes
+import net.corda.core.until
 import net.corda.core.utilities.loggerFor
 import net.corda.demobench.model.NodeConfig
 import net.corda.demobench.readErrorLines
 import java.io.IOException
+import java.net.HttpURLConnection
+import java.net.URI
+import java.time.Instant
 import java.util.concurrent.Executors
+import java.util.concurrent.TimeoutException
+import kotlin.concurrent.thread
 
 class WebServer internal constructor(private val webServerController: WebServerController) : AutoCloseable {
     private companion object {
@@ -15,13 +26,12 @@ class WebServer internal constructor(private val webServerController: WebServerC
     private var process: Process? = null
 
     @Throws(IOException::class)
-    fun open(config: NodeConfig, onExit: (NodeConfig) -> Unit) {
+    fun open(config: NodeConfig): ListenableFuture<URI> {
         val nodeDir = config.nodeDir.toFile()
 
         if (!nodeDir.isDirectory) {
             log.warn("Working directory '{}' does not exist.", nodeDir.absolutePath)
-            onExit(config)
-            return
+            return SettableFuture.create()
         }
 
         try {
@@ -46,12 +56,18 @@ class WebServer internal constructor(private val webServerController: WebServerC
                 } else {
                     log.error("Web Server for '{}' has exited (value={}, {})", config.legalName, exitValue, errors)
                 }
-
-                onExit(config)
             }
+
+            val future = SettableFuture.create<URI>()
+            thread {
+                future.catch {
+                    log.info("Waiting for web server for ${config.legalName} to start ...")
+                    waitForStart(config.webPort)
+                }
+            }
+            return future
         } catch (e: IOException) {
             log.error("Failed to launch Web Server for '{}': {}", config.legalName, e.message)
-            onExit(config)
             throw e
         }
     }
@@ -68,4 +84,24 @@ class WebServer internal constructor(private val webServerController: WebServerC
             log.error("Failed to close stream: '{}'", e.message)
         }
     }
+
+    private fun waitForStart(port: Int): URI {
+        val url = URI("http://localhost:$port/")
+        val rateLimiter = RateLimiter.create(2.0)
+        val start = Instant.now()
+        val timeout = 1.minutes
+        while ((start until Instant.now()) < timeout) {
+            try {
+                rateLimiter.acquire()
+                val conn = url.toURL().openConnection() as HttpURLConnection
+                conn.connectTimeout = 500  // msec
+                conn.requestMethod = "HEAD"
+                conn.connect()
+                conn.disconnect()
+                return url
+            } catch(e: IOException) {
+            }
+        }
+        throw TimeoutException("Web server did not start within ${timeout.seconds} seconds")
+    }
 }