diff options
Diffstat (limited to 'kamon-status-page/src/main/scala/kamon/status/page/StatusPageServer.scala')
| -rw-r--r-- | kamon-status-page/src/main/scala/kamon/status/page/StatusPageServer.scala | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/kamon-status-page/src/main/scala/kamon/status/page/StatusPageServer.scala b/kamon-status-page/src/main/scala/kamon/status/page/StatusPageServer.scala new file mode 100644 index 00000000..cf6588bf --- /dev/null +++ b/kamon-status-page/src/main/scala/kamon/status/page/StatusPageServer.scala @@ -0,0 +1,117 @@ +package kamon.status.page + +import java.io.InputStream +import java.util.Collections +import java.util.concurrent.{ExecutorService, Executors} + +import fi.iki.elonen.NanoHTTPD +import fi.iki.elonen.NanoHTTPD.Response.{Status => StatusCode} +import kamon.status.Status + +import scala.collection.JavaConverters.asScalaBufferConverter + +/** + * Exposes an embedded HTTP server based on NanoHTTP. + */ +class StatusPageServer(hostname: String, port: Int, resourceLoader: ClassLoader, status: Status) + extends NanoHTTPD(hostname, port) { + + private val RootResourceDirectory = "status-page" + private val ResourceExtensionRegex = ".*\\.([a-zA-Z0-9]*)".r + + override def serve(session: NanoHTTPD.IHTTPSession): NanoHTTPD.Response = { + if(session.getMethod() == NanoHTTPD.Method.GET) { + if(session.getUri().startsWith("/status")) { + + // Serve the current status data on Json. + session.getUri() match { + case "/status/settings" => json(status.settings()) + case "/status/modules" => json(status.moduleRegistry()) + case "/status/metrics" => json(status.metricRegistry()) + case "/status/instrumentation" => json(status.instrumentation()) + case _ => NotFound + } + + } else { + + // Serve resources from the status page folder. + val requestedResource = if (session.getUri() == "/") "/index.html" else session.getUri() + val resourcePath = RootResourceDirectory + requestedResource + val resourceStream = resourceLoader.getResourceAsStream(resourcePath) + + if (resourceStream == null) NotFound else resource(requestedResource, resourceStream) + } + + } else NotAllowed + } + + override def start(): Unit = { + setAsyncRunner(new ThreadPoolRunner(Executors.newFixedThreadPool(2))) + start(NanoHTTPD.SOCKET_READ_TIMEOUT, false) + } + + private def mimeType(resource: String): String = { + val ResourceExtensionRegex(resourceExtension) = resource + resourceExtension match { + case "css" => "text/css" + case "js" => "application/javascript" + case "ico" => "image/x-icon" + case "svg" => "image/svg+xml" + case "html" => "text/html" + case "woff2" => "font/woff2" + case _ => "text/plain" + } + } + + private def json[T](instance: T)(implicit marshalling: JsonMarshalling[T]) = { + val builder = new java.lang.StringBuilder() + marshalling.toJson(instance, builder) + + val response = NanoHTTPD.newFixedLengthResponse(StatusCode.OK, "application/json", builder.toString()) + response.closeConnection(true) + response + } + + private def resource(name: String, stream: InputStream) = { + val response = NanoHTTPD.newChunkedResponse(StatusCode.OK, mimeType(name), stream) + response.closeConnection(true) + response + } + + private val NotAllowed = NanoHTTPD.newFixedLengthResponse( + StatusCode.METHOD_NOT_ALLOWED, + NanoHTTPD.MIME_PLAINTEXT, + "Only GET requests are allowed." + ) + + private val NotFound = NanoHTTPD.newFixedLengthResponse( + StatusCode.NOT_FOUND, + NanoHTTPD.MIME_PLAINTEXT, + "The requested resource was not found." + ) + + // Closing the connections will ensure that the thread pool will not be exhausted by keep alive + // connections from the browsers. + NotAllowed.closeConnection(true) + NotFound.closeConnection(true) + + + /** + * AsyncRunner that uses a thread pool for handling requests rather than spawning a new thread for each request (as + * the default runner does). + */ + private class ThreadPoolRunner(executorService: ExecutorService) extends NanoHTTPD.AsyncRunner { + final private val _openRequests = Collections.synchronizedList(new java.util.LinkedList[NanoHTTPD#ClientHandler]()) + + override def closeAll(): Unit = + _openRequests.asScala.foreach(_.close()) + + override def closed(clientHandler: NanoHTTPD#ClientHandler): Unit = + _openRequests.remove(clientHandler) + + override def exec(clientHandler: NanoHTTPD#ClientHandler): Unit = { + executorService.submit(clientHandler) + _openRequests.add(clientHandler) + } + } +}
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