1 files changed, 206 insertions, 0 deletions
diff --git a/trunk/etherpad/src/etherpad/pad/pad_migrations.js b/trunk/etherpad/src/etherpad/pad/pad_migrations.js
new file mode 100644
index 0000000..e81cf63
--- /dev/null
+++ b/trunk/etherpad/src/etherpad/pad/pad_migrations.js
@@ -0,0 +1,206 @@
+/**
+ * Copyright 2009 Google Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS-IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import("sqlbase.sqlobj");
+import("etherpad.pad.model");
+import("etherpad.pad.easysync2migration");
+import("sqlbase.sqlcommon");
+import("sqlbase.sqlobj");
+import("etherpad.log");
+import("etherpad.pne.pne_utils");
+jimport("java.util.concurrent.ConcurrentHashMap");
+jimport("java.lang.System");
+jimport("java.util.ArrayList");
+jimport("java.util.Collections");
+
+function onStartup() {
+  if (! appjet.cache.pad_migrations) {
+    appjet.cache.pad_migrations = {};
+  }
+
+  // this part can be removed when all pads are migrated on pad.spline.inf.fu-berlin.de
+  //if (! pne_utils.isPNE()) {
+  //  System.out.println("Building cache for live migrations...");
+  //  initLiveMigration();
+  //}
+}
+
+function initLiveMigration() {
+
+  if (! appjet.cache.pad_migrations) {
+    appjet.cache.pad_migrations = {};
+  }
+  appjet.cache.pad_migrations.doingAnyLiveMigrations = true;
+  appjet.cache.pad_migrations.doingBackgroundLiveMigrations = true;
+  appjet.cache.pad_migrations.padMap = new ConcurrentHashMap();
+
+  // presence of a pad in padMap indicates migration is needed
+  var padMap = _padMap();
+  var migrationsNeeded = sqlobj.selectMulti("PAD_SQLMETA", {version: 1});
+  migrationsNeeded.forEach(function(obj) {
+    padMap.put(String(obj.id), {from: obj.version});
+  });
+}
+
+function _padMap() {
+  return appjet.cache.pad_migrations.padMap;
+}
+
+function _doingItLive() {
+  return !! appjet.cache.pad_migrations.doingAnyLiveMigrations;
+}
+
+function checkPadStatus(padId) {
+  if (! _doingItLive()) {
+    return "ready";
+  }
+  var info = _padMap().get(padId);
+  if (! info) {
+    return "ready";
+  }
+  else if (info.migrating) {
+    return "migrating";
+  }
+  else {
+    return "oldversion";
+  }
+}
+
+function ensureMigrated(padId, async) {
+  if (! _doingItLive()) {
+    return false;
+  }
+
+  var info = _padMap().get(padId);
+  if (! info) {
+    // pad is up-to-date
+    return false;
+  }
+  else if (async && info.migrating) {
+    // pad is already being migrated, don't wait on the lock
+    return false;
+  }
+
+  return model.doWithPadLock(padId, function() {
+    // inside pad lock...
+    var info = _padMap().get(padId);
+    if (!info) {
+      return false;
+    }
+    // migrate from version 1 to version 2 in a transaction
+    var migrateSucceeded = false;
+    try {
+      info.migrating = true;
+      log.info("Migrating pad "+padId+" from version 1 to version 2...");
+
+      var success = false;
+      var whichTry = 1;
+      while ((! success) && whichTry <= 3) {
+        success = sqlcommon.inTransaction(function() {
+          try {
+            easysync2migration.migratePad(padId);
+            sqlobj.update("PAD_SQLMETA", {id: padId}, {version: 2});
+            return true;
+          }
+          catch (e if (e.toString().indexOf("try restarting transaction") >= 0)) {
+            whichTry++;
+            return false;
+          }
+        });
+        if (! success) {
+          java.lang.Thread.sleep(Math.floor(Math.random()*200));
+        }
+      }
+      if (! success) {
+        throw new Error("too many retries");
+      }
+
+      migrateSucceeded = true;
+      log.info("Migrated pad "+padId+".");
+      _padMap().remove(padId);
+    }
+    finally {
+      info.migrating = false;
+      if (! migrateSucceeded) {
+	log.info("Migration failed for pad "+padId+".");
+        throw new Error("Migration failed for pad "+padId+".");
+      }
+    }
+    return true;
+  });
+}
+
+function numUnmigratedPads() {
+  if (! _doingItLive()) {
+    return 0;
+  }
+
+  return _padMap().size();
+}
+
+////////// BACKGROUND MIGRATIONS
+
+function _logPadMigration(runnerId, padNumber, padTotal, timeMs, fourCharResult, padId) {
+  log.custom("pad_migrations", {
+    runnerId: runnerId,
+    padNumber: Math.round(padNumber+1),
+    padTotal: Math.round(padTotal),
+    timeMs: Math.round(timeMs),
+    fourCharResult: fourCharResult,
+    padId: padId});
+}
+
+function _getNeededMigrationsArrayList(filter) {
+  var L = new ArrayList(_padMap().keySet());
+  for(var i=L.size()-1; i>=0; i--) {
+    if (! filter(String(L.get(i)))) {
+      L.remove(i);
+    }
+  }
+  return L;
+}
+
+function runBackgroundMigration(residue, modulus, runnerId) {
+  var L = _getNeededMigrationsArrayList(function(padId) {
+    return (padId.charCodeAt(0) % modulus) == residue;
+  });
+  Collections.shuffle(L);
+
+  var totalPads = L.size();
+  for(var i=0;i<totalPads;i++) {
+    if (! appjet.cache.pad_migrations.doingBackgroundLiveMigrations) {
+      break;
+    }
+    var padId = L.get(i);
+    var result = "FAIL";
+    var t1 = System.currentTimeMillis();
+    try {
+      if (ensureMigrated(padId, true)) {
+        result = " OK "; // migrated successfully
+      }
+      else {
+        result = " -- "; // no migration needed after all
+      }
+    }
+    catch (e) {
+      // e just says "migration failed", but presumably
+      // inTransaction() printed a stack trace.
+      // result == "FAIL", do nothing.
+    }
+    var t2 = System.currentTimeMillis();
+    _logPadMigration(runnerId, i, totalPads, t2 - t1, result, padId);
+  }
+}