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1 files changed, 195 insertions, 0 deletions

diff --git a/container-core/src/main/java/com/yahoo/container/handler/VipStatusHandler.java b/container-core/src/main/java/com/yahoo/container/handler/VipStatusHandler.java
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+++ b/container-core/src/main/java/com/yahoo/container/handler/VipStatusHandler.java
@@ -0,0 +1,195 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.container.handler;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import com.google.inject.Inject;
+import com.yahoo.container.core.VipStatusConfig;
+import com.yahoo.container.jdisc.HttpRequest;
+import com.yahoo.container.jdisc.HttpResponse;
+import com.yahoo.container.jdisc.ThreadedHttpRequestHandler;
+import com.yahoo.container.logging.AccessLog;
+import com.yahoo.jdisc.Metric;
+import com.yahoo.log.LogLevel;
+import com.yahoo.text.Utf8;
+import com.yahoo.vespa.defaults.Defaults;
+
+/**
+ * Transmit status to VIP from file or memory. Bind this to
+ * "http://{@literal *}/status.html" to serve VIP status requests.
+ *
+ * @author <a href="mailto:steinar@yahoo-inc.com">Steinar Knutsen</a>
+ */
+public final class VipStatusHandler extends ThreadedHttpRequestHandler {
+
+    private static final Logger log = Logger.getLogger(VipStatusHandler.class.getName());
+
+    private static final String NUM_REQUESTS_METRIC = "jdisc.http.requests.status";
+
+    private final boolean accessDisk;
+    private final File statusFile;
+    private final VipStatus vipStatus;
+    private final boolean noSearchBackendsImpliesOutOfService;
+
+    private volatile boolean previouslyInRotation = true;
+
+    // belongs in the response, but that's not a static class
+    static final String OK_MESSAGE = "<title>OK</title>\n";
+    static final byte[] VIP_OK = Utf8.toBytes(OK_MESSAGE);
+
+    class StatusResponse extends HttpResponse {
+
+        static final String COULD_NOT_FIND_STATUS_FILE = "Could not find status file.\n";
+        static final String NO_SEARCH_BACKENDS = "No search backends available, VIP status disabled.";
+        private static final String TEXT_HTML = "text/html";
+        private String contentType = TEXT_HTML;
+        private byte[] data = null;
+        private File file = null;
+
+        private StatusResponse() {
+            super(com.yahoo.jdisc.http.HttpResponse.Status.OK); // status may be overwritten below
+            if (noSearchBackendsImpliesOutOfService && !vipStatus.isInRotation()) {
+                searchContainerOutOfService();
+            } else if (accessDisk) {
+                preSlurpFile();
+            } else {
+                vipRespond();
+            }
+        }
+
+        @Override
+        public void render(OutputStream stream) throws IOException {
+            if (file != null) {
+                readAndWrite(stream);
+            }
+            else if (data != null) {
+                stream.write(data);
+            }
+            else {
+                throw new IllegalStateException(
+                        "Neither file nor hardcoded data. This is a bug, please notify the Vespa team.");
+            }
+            stream.close();
+        }
+
+        private void readAndWrite(OutputStream stream) throws IOException {
+            InputStream input;
+            int lastRead = 0;
+            input = new FileInputStream(file);
+            try {
+                while (lastRead != -1) {
+                    byte[] buffer = new byte[5000];
+                    lastRead = input.read(buffer);
+                    if (lastRead > 0) {
+                        stream.write(buffer, 0, lastRead);
+                    }
+                }
+            } finally {
+                stream.close();
+                input.close();
+            }
+        }
+
+        private void preSlurpFile() {
+            try {
+                if (!statusFile.exists()) {
+                    fileNotFound();
+                    return;
+                }
+                if (!statusFile.canRead()) {
+                    accessDenied();
+                    return;
+                }
+            } catch (SecurityException e) {
+                internalError();
+                return;
+            }
+            this.file = statusFile;
+        }
+
+        private void accessDenied() {
+            contentType = "text/plain";
+            data = Utf8.toBytes("Status file inaccessible.\n");
+            setStatus(com.yahoo.jdisc.http.HttpResponse.Status.NOT_FOUND);
+        }
+
+        private void internalError() {
+            contentType = "text/plain";
+            data = Utf8.toBytes("Internal error while fetching status file.\n");
+            setStatus(com.yahoo.jdisc.http.HttpResponse.Status.NOT_FOUND);
+        }
+
+        private void fileNotFound() {
+            contentType = "text/plain";
+            data = Utf8.toBytes(COULD_NOT_FIND_STATUS_FILE);
+            setStatus(com.yahoo.jdisc.http.HttpResponse.Status.NOT_FOUND);
+        }
+
+        private void vipRespond() {
+            data = VIP_OK;
+        }
+
+        /**
+         * Behaves like a VIP status response file has been deleted.
+         */
+        private void searchContainerOutOfService() {
+            contentType = "text/plain";
+            data = Utf8.toBytes(NO_SEARCH_BACKENDS);
+            setStatus(com.yahoo.jdisc.http.HttpResponse.Status.NOT_FOUND);
+        }
+
+        @Override
+        public String getContentType() {
+            return contentType;
+        }
+
+        @Override
+        public String getCharacterEncoding() {
+            return null;
+        }
+    }
+
+    public VipStatusHandler(Executor executor, VipStatusConfig vipConfig, Metric metric) {
+        this(executor, vipConfig, metric, null);
+    }
+
+    @Inject
+    public VipStatusHandler(Executor executor, VipStatusConfig vipConfig, Metric metric, VipStatus vipStatus) {
+        super(executor, metric);
+        this.accessDisk = vipConfig.accessdisk();
+        this.statusFile = new File(Defaults.getDefaults().underVespaHome(vipConfig.statusfile()));
+        this.noSearchBackendsImpliesOutOfService = vipConfig.noSearchBackendsImpliesOutOfService();
+        this.vipStatus = vipStatus;
+    }
+
+    @Override
+    public HttpResponse handle(HttpRequest request) {
+        if (metric != null)
+            metric.add(NUM_REQUESTS_METRIC, 1, null);
+        if (noSearchBackendsImpliesOutOfService) {
+            updateAndLogRotationState();
+        }
+        return new StatusResponse();
+    }
+
+    private void updateAndLogRotationState() {
+        final boolean currentlyInRotation = vipStatus.isInRotation();
+        final boolean previousRotationAnswer = previouslyInRotation;
+        previouslyInRotation = currentlyInRotation;
+
+        if (previousRotationAnswer != currentlyInRotation) {
+            if (currentlyInRotation) {
+                log.log(LogLevel.INFO, "Putting container back into rotation by serving status.html again.");
+            } else {
+                log.log(LogLevel.WARNING, "Removing container from rotation by no longer serving status.html.");
+            }
+        }
+    }
+
+}