made it possible the the config contains severall backends

conf/config.properties

@@ -115,7 +115,7 @@ DoS.servicereduction = 1000
 # peer-to-peer back-end: this is used to assign a 'shadow' peer which
 # receives all message data that this peer creates
 # if you don't want a p2p operation,remove the backend value
-backend=http://api.loklak.org
+backend=http://api.loklak.org,http://root.loklak.org
 backend.push.enabled=true
 
 # peer-to-peer front peer: this is used to assign scraping activities to

src/org/loklak/Caretaker.java

@@ -75,7 +75,7 @@ public void shutdown() {
     public void run() {
         Thread.currentThread().setName("CARETAKER");
         // send a message to other peers that I am alive
-        String[] remote = DAO.getConfig("backend", new String[0], ",");
+        String[] backends = DAO.getBackend();
         int maxRetries = Integer.valueOf(DAO.getConfig("caretaker.backendpush.retries", "5"));
         int backOffParameter = Integer.valueOf(DAO.getConfig("caretaker.backendpush.backoff", "3000"));
 
@@ -96,7 +96,7 @@ public void run() {
             // check ping
             if (System.currentTimeMillis() - helloPeriod > helloTime) {
                 helloTime = System.currentTimeMillis();
-                HelloService.propagate(remote);
+                HelloService.propagate(backends);
             }
 
             // clear caches
@@ -111,28 +111,28 @@ public void run() {
 
             // peer-to-peer operation
             Timeline tl = DAO.outgoingMessages.takeTimelineMin(Timeline.Order.CREATED_AT, TIMELINE_PUSH_MINSIZE, TIMELINE_PUSH_MAXSIZE);
-            if (tl != null && tl.size() > 0 && remote.length > 0) {
+            if (tl != null && tl.size() > 0 && backends.length > 0) {
                 // transmit the timeline
                 long start = System.currentTimeMillis();
-                boolean success = PushServlet.push(remote, tl);
+                boolean success = PushServlet.push(backends, tl);
                 if (success) {
-                    DAO.log("success pushing " + tl.size() + " messages to backend " + Arrays.toString(remote) + " in 1st attempt in " + (System.currentTimeMillis() - start) + " ms");
+                    DAO.log("success pushing " + tl.size() + " messages to backend " + Arrays.toString(backends) + " in 1st attempt in " + (System.currentTimeMillis() - start) + " ms");
                 }
                 if (!success) {
                     // we should try again.. but not an infinite number because then
                     // our timeline in RAM would fill up our RAM creating a memory leak
                     retrylook: for (int retry = 0; retry < maxRetries; retry++) {
                         // give back-end time to recover
                         try {Thread.sleep((retry + 1) * backOffParameter);} catch (InterruptedException e) {}
-                        DAO.log("trying to push (again) " + tl.size() + " messages to backend " + Arrays.toString(remote) + ", attempt #" + (retry + 1) + "/5");
+                        DAO.log("trying to push (again) " + tl.size() + " messages to backend " + Arrays.toString(backends) + ", attempt #" + (retry + 1) + "/5");
                         start = System.currentTimeMillis();
-                        if (PushServlet.push(remote, tl)) {
-                            DAO.log("success pushing " + tl.size() + " messages to backend " + Arrays.toString(remote) + " in " + (retry + 2) + ". attempt in " + (System.currentTimeMillis() - start) + " ms");
+                        if (PushServlet.push(backends, tl)) {
+                            DAO.log("success pushing " + tl.size() + " messages to backend " + Arrays.toString(backends) + " in " + (retry + 2) + ". attempt in " + (System.currentTimeMillis() - start) + " ms");
                             success = true;
                             break retrylook;
                         }
                     }
-                    if (!success) DAO.log("failed pushing " + tl.size() + " messages to backend " + Arrays.toString(remote));
+                    if (!success) DAO.log("failed pushing " + tl.size() + " messages to backend " + Arrays.toString(backends));
                 }
                 busy = true;
             }
@@ -147,7 +147,7 @@ public void run() {
             // run some harvesting steps
             if (DAO.getConfig("retrieval.forbackend.enabled", false) &&
                 DAO.getConfig("backend.push.enabled", false) &&
-                (DAO.getConfig("backend", "").length() > 0) &&
+                (DAO.getBackend().length > 0) &&
                 DAO.outgoingMessages.timelineSize() < TIMELINE_PUSH_MAXSIZE) {
                 int retrieval_forbackend_concurrency = (int) DAO.getConfig("retrieval.forbackend.concurrency", 1);
                 int retrieval_forbackend_loops = (int) DAO.getConfig("retrieval.forbackend.loops", 10);

src/org/loklak/api/admin/StatusService.java

@@ -64,6 +64,18 @@ public JSONObject getDefaultPermissions(BaseUserRole baseUserRole) {
     }
 
 
+    public static JSONObject status(final String[] protocolhostportstubs) throws IOException {
+        IOException e = null;
+        for (String protocolhostportstub: protocolhostportstubs) {
+            try {
+                return status(protocolhostportstub);
+            } catch (IOException ee) {
+                e = ee;
+            }
+        }
+        throw e == null ? new IOException("no url given") : e;
+    }
+
     public static JSONObject status(final String protocolhostportstub) throws IOException {
         final String urlstring = protocolhostportstub + "/api/status.json";
         byte[] response = ClientConnection.downloadPeer(urlstring);
@@ -116,11 +128,11 @@ public static JSONObject getSystemConfig(Runtime runtime) throws Exception {
     }
 
     public static JSONObject getIndexConfig() throws Exception {
-        final String backend = DAO.getConfig("backend", "");
+        final String[] backend = DAO.getBackend();
         final boolean backend_push = DAO.getConfig("backend.push.enabled", false);
         JSONObject backend_status = null;
         JSONObject backend_status_index_sizes = null;
-        if (backend.length() > 0 && !backend_push) {
+        if (backend.length > 0 && !backend_push) {
             try {
                 backend_status = StatusService.status(backend);
                 backend_status_index_sizes = backend_status == null ? null : (JSONObject) backend_status.get("index_sizes");

src/org/loklak/api/p2p/HelloService.java

@@ -69,11 +69,11 @@ public static void propagate(final String[] hoststubs) {
         String peername = (String) DAO.getConfig("peername", "anonymous");
 
         // retrieve some simple statistics from the index
-        final String backend = DAO.getConfig("backend", "");
+        final String[] backend = DAO.getBackend();
         final boolean backend_push = DAO.getConfig("backend.push.enabled", false);
         JSONObject backend_status = null;
         JSONObject backend_status_index_sizes = null;
-        if (backend.length() > 0 && !backend_push) {
+        if (backend.length > 0 && !backend_push) {
             try {
                 backend_status = StatusService.status(backend);
             } catch (IOException e) {

src/org/loklak/api/search/SearchServlet.java

@@ -72,21 +72,31 @@ public class SearchServlet extends HttpServlet {
     public final static String frontpeer_hash = Integer.toHexString(Integer.MAX_VALUE - 1);
 
     // possible values: cache, twitter, all
-    public static Timeline search(final String protocolhostportstub, final String query, final ArrayList<String> filterList, final Timeline.Order order, final String source, final int count, final int timezoneOffset, final String provider_hash, final long timeout) throws IOException {
+    public static Timeline search(final String[] protocolhostportstubs, final String query, final ArrayList<String> filterList, final Timeline.Order order, final String source, final int count, final int timezoneOffset, final String provider_hash, final long timeout) throws IOException {
         Timeline tl = new Timeline(order);
         if ("".equals(query)) return tl;
         String urlstring = "";
         String filterString = "";
 
         try {
-            urlstring = protocolhostportstub + "/api/search.json?q=" + URLEncoder.encode(query.replace(' ', '+'), "UTF-8") + "&timezoneOffset=" + timezoneOffset + "&maximumRecords=" + count + "&source=" + (source == null ? "all" : source) + "&minified=true&shortlink=false&timeout=" + timeout;
+            byte[] jsonb = null;
+            IOException ee = null;
+            backendloop: for (String protocolhostportstub: protocolhostportstubs) {
+                ee = null;
+                try {
+                    urlstring = protocolhostportstub + "/api/search.json?q=" + URLEncoder.encode(query.replace(' ', '+'), "UTF-8") + "&timezoneOffset=" + timezoneOffset + "&maximumRecords=" + count + "&source=" + (source == null ? "all" : source) + "&minified=true&shortlink=false&timeout=" + timeout;
+
+                    if (!"".equals(filterString = String.join(", ", filterList))) {
+                        urlstring = urlstring + "&filter=" + filterString;
+                    }
 
-            if(!"".equals(filterString = String.join(", ", filterList))) {
-                urlstring = urlstring + "&filter=" + filterString;
+                    jsonb = ClientConnection.downloadPeer(urlstring);
+                    break backendloop;
+                } catch (IOException e) {
+                    ee = e;
+                }
             }
-
-            byte[] jsonb = ClientConnection.downloadPeer(urlstring);
-            if (jsonb == null || jsonb.length == 0) throw new IOException("empty content from " + protocolhostportstub);
+            if (jsonb == null || jsonb.length == 0) throw ee == null ? new IOException("empty content from " + protocolhostportstubs) : ee;
             String jsons = UTF8.String(jsonb);
             JSONObject json = new JSONObject(jsons);
             if (json == null || json.length() == 0) return tl;
@@ -118,10 +128,10 @@ public static Timeline search(final String protocolhostportstub, final String qu
     }
 
     public static Timeline search(
-            final String protocolhostportstub, final String query, final Timeline.Order order,
+            final String[] protocolhostportstubs, final String query, final Timeline.Order order,
             final String source, final int count, final int timezoneOffset,
             final String provider_hash, final long timeout) throws IOException {
-        return search(protocolhostportstub, query, new ArrayList<>(), order, source, count, timezoneOffset, provider_hash, timeout);
+        return search(protocolhostportstubs, query, new ArrayList<>(), order, source, count, timezoneOffset, provider_hash, timeout);
     }
 
     @Override
@@ -520,7 +530,7 @@ private static void setTwitterMetaData(JSONObject metadata, final int startRecor
 
     public static void main(String[] args) {
         try {
-            Timeline tl = search("http://loklak.org", "beer", Timeline.Order.CREATED_AT, "cache", 20, -120, backend_hash, 10000);
+            Timeline tl = search(new String[]{"http://root.loklak.org"}, "beer", Timeline.Order.CREATED_AT, "cache", 20, -120, backend_hash, 10000);
             System.out.println(tl.toJSON(false, "search_metadata", "statuses").toString(2));
         } catch (IOException e) {
             DAO.severe(e);

src/org/loklak/api/search/SuggestServlet.java

@@ -65,7 +65,7 @@ public class SuggestServlet extends HttpServlet {
     public static Map<Integer, JSONObject> cache = new ConcurrentHashMap<>();
 
     public static ResultList<QueryEntry> suggest(
-            final String protocolhostportstub,
+            final String[] protocolhostportstubs,
             final String q,
             final String source,
             final int count,
@@ -80,22 +80,32 @@ public static ResultList<QueryEntry> suggest(
         int httpsport = (int) DAO.getConfig("port.https", 9443);
         String peername = (String) DAO.getConfig("peername", "anonymous");
         ResultList<QueryEntry>  rl = new ResultList<QueryEntry>();
-        String urlstring = "";
-        urlstring = protocolhostportstub + "/api/suggest.json?q=" + URLEncoder.encode(q.replace(' ', '+'), "UTF-8") +
-                "&timezoneOffset=" + timezoneOffset +
-                "&count=" + count +
-                "&source=" + (source == null ? "all" : source) +
-                (order == null ? "" : ("&order=" + order)) +
-                (orderby == null ? "" : ("&orderby=" + orderby)) +
-                (since == null ? "" : ("&since=" + since)) +
-                (until == null ? "" : ("&until=" + until)) +
-                (selectby == null ? "" : ("&selectby=" + selectby)) +
-                (random < 0 ? "" : ("&random=" + random)) +
-                "&minified=true" +
-                "&port.http=" + httpport +
-                "&port.https=" + httpsport +
-                "&peername=" + peername;
-        byte[] response = ClientConnection.downloadPeer(urlstring);
+        byte[] response = null;
+        IOException ee = null;
+        backendloop: for (String protocolhostportstub: protocolhostportstubs) {
+            try {
+                ee = null;
+                String urlstring = protocolhostportstub + "/api/suggest.json?q=" + URLEncoder.encode(q.replace(' ', '+'), "UTF-8") +
+                        "&timezoneOffset=" + timezoneOffset +
+                        "&count=" + count +
+                        "&source=" + (source == null ? "all" : source) +
+                        (order == null ? "" : ("&order=" + order)) +
+                        (orderby == null ? "" : ("&orderby=" + orderby)) +
+                        (since == null ? "" : ("&since=" + since)) +
+                        (until == null ? "" : ("&until=" + until)) +
+                        (selectby == null ? "" : ("&selectby=" + selectby)) +
+                        (random < 0 ? "" : ("&random=" + random)) +
+                        "&minified=true" +
+                        "&port.http=" + httpport +
+                        "&port.https=" + httpsport +
+                        "&peername=" + peername;
+                response = ClientConnection.downloadPeer(urlstring);
+                break backendloop;
+            } catch (IOException e) {
+                ee = e;
+            }
+        }
+        if (response == null && ee != null) throw ee;
         if (response == null || response.length == 0) return rl;
         String responseString = UTF8.String(response);
         if (responseString == null || responseString.length() == 0 || responseString.startsWith("<")) {
@@ -228,7 +238,7 @@ protected void doGet(HttpServletRequest request, HttpServletResponse response) t
 
     public static void main(String[] args) {
         try {
-            ResultList<QueryEntry> rl = suggest("http://loklak.org", "","query",1000,"asc","retrieval_next",DateParser.getTimezoneOffset(),null,"now","retrieval_next",3);
+            ResultList<QueryEntry> rl = suggest(new String[]{"http://root.loklak.org"}, "","query",1000,"asc","retrieval_next",DateParser.getTimezoneOffset(),null,"now","retrieval_next",3);
             for (QueryEntry qe: rl) {
                 System.out.println(UTF8.String(qe.toJSONBytes()));
             }

src/org/loklak/data/DAO.java

@@ -1515,10 +1515,14 @@ public static ArrayList<String> getFrontPeers() {
         return getBestPeers(testpeers);
     }
 
+    public static String[] getBackend() {
+        return DAO.getConfig("backend", new String[]{"http://api.loklak.org"}, ",");
+    }
+
     public static List<String> getBackendPeers() {
         List<String> testpeers = new ArrayList<>();
         if (backendPeerCache.size() == 0) {
-            String[] remote = DAO.getConfig("backend", new String[0], ",");
+            final String[] remote = DAO.getBackend();
             for (String peer: remote) backendPeerCache.add(peer);
         }
         testpeers.addAll(backendPeerCache);
@@ -1545,7 +1549,7 @@ public static Timeline searchOnOtherPeers(final List<String> remote, final Strin
             String peer = remote.get(pick);
             long start = System.currentTimeMillis();
             try {
-                Timeline tl = SearchServlet.search(peer, q, filterList, order, source, count, timezoneOffset, provider_hash, timeout);
+                Timeline tl = SearchServlet.search(new String[]{peer}, q, filterList, order, source, count, timezoneOffset, provider_hash, timeout);
                 peerLatency.put(peer, System.currentTimeMillis() - start);
                 // to show which peer was used for the retrieval, we move the picked peer to the front of the list
                 if (pick != 0) remote.add(0, remote.remove(pick));

src/org/loklak/data/OutgoingMessageBuffer.java

@@ -37,7 +37,7 @@ public OutgoingMessageBuffer() {
     }
 
     public void transmitTimelineToBackend(Timeline tl) {
-        if (DAO.getConfig("backend", new String[0], ",").length > 0) {
+        if (DAO.getBackend().length > 0) {
             boolean clone = false;
             for (TwitterTweet message: tl) {
                 if (!message.getSourceType().propagate()) {clone = true; break;}
@@ -56,7 +56,7 @@ public void transmitTimelineToBackend(Timeline tl) {
 
     public void transmitMessage(final TwitterTweet tweet, final UserEntry user) {
         if (!tweet.getSourceType().propagate()) return;
-        if (DAO.getConfig("backend", new String[0], ",").length <= 0) return;
+        if (DAO.getBackend().length <= 0) return;
         if (!DAO.getConfig("backend.push.enabled", false)) return;
         Timeline tl = this.pushToBackendTimeline.poll();
         if (tl == null) tl = new Timeline(Timeline.Order.CREATED_AT);

src/org/loklak/harvester/PushThread.java

@@ -5,10 +5,10 @@
 import org.loklak.objects.Timeline;
 
 public class PushThread implements Runnable {
-    private String peer;
+    private String[] peers;
     private Timeline tl;
-    public PushThread(String peer, Timeline tl) {
-        this.peer = peer;
+    public PushThread(String[] peers, Timeline tl) {
+        this.peers = peers;
         this.tl = tl;
     }
     @Override
@@ -17,7 +17,7 @@ public void run() {
         for (int i = 0; i < 5; i++) {
             try {
                 long start = System.currentTimeMillis();
-                success = PushServlet.push(new String[]{peer}, tl);
+                success = PushServlet.push(this.peers, tl);
                 if (success) {
                     DAO.log("retrieval of " + tl.size() + " new messages for q = " + tl.getQuery() +
                             ", pushed to backend synchronously in " + (System.currentTimeMillis() - start) + " ms; amount = " + tl.size());

src/org/loklak/harvester/strategy/ClassicHarvester.java

@@ -74,7 +74,7 @@ public void checkContext(String s, boolean front) {
     }
 
     public int harvest() {
-        String backend = DAO.getConfig("backend","http://api.loklak.org");
+        String[] backend = DAO.getBackend();
 
         if (random.nextInt(100) != 0 && hitsOnBackend < HITS_LIMIT_4_QUERIES && pendingQueries.size() == 0 && pendingContext.size() > 0) {
             // harvest using the collected keys instead using the queries

src/org/loklak/harvester/strategy/KaizenHarvester.java

@@ -35,7 +35,7 @@
  */
 public class KaizenHarvester implements Harvester {
 
-    private final String BACKEND;
+    private final String[] BACKEND;
     private final int SUGGESTIONS_COUNT;
     private final int SUGGESTIONS_RANDOM;
     private final int PLACE_RADIUS;
@@ -50,7 +50,7 @@ public class KaizenHarvester implements Harvester {
     private Twitter twitter = null;
 
     public KaizenHarvester(KaizenQueries queries) {
-        BACKEND = DAO.getConfig("backend", "http://loklak.org");
+        BACKEND = DAO.getBackend();
         SUGGESTIONS_COUNT = DAO.getConfig("harvester.kaizen.suggestions_count", 1000);
         SUGGESTIONS_RANDOM = DAO.getConfig("harvester.kaizen.suggestions_random", 5);
         PLACE_RADIUS = DAO.getConfig("harvester.kaizen.place_radius", 5);