add autodisablingdatabase

src/main/scala/com/twitter/querulous/AutoDisabler.scala

@@ -0,0 +1,35 @@
+package com.twitter.querulous
+
+import com.twitter.xrayspecs.{Time, Duration}
+import com.twitter.xrayspecs.TimeConversions._
+import java.sql.{SQLException, SQLIntegrityConstraintViolationException}
+
+
+trait AutoDisabler {
+  protected val disableErrorCount: Int
+  protected val disableDuration: Duration
+
+  private var disabledUntil: Time = Time.never
+  private var consecutiveErrors = 0
+
+  protected def throwIfDisabled() {
+    synchronized {
+      if (Time.now < disabledUntil) {
+        throw new SQLException("Server is temporarily disabled")
+      }
+    }
+  }
+
+  protected def noteOperationOutcome(success: Boolean) {
+    synchronized {
+      if (success) {
+        consecutiveErrors = 0
+      } else {
+        consecutiveErrors += 1
+        if (consecutiveErrors >= disableErrorCount) {
+          disabledUntil = disableDuration.fromNow
+        }
+      }
+    }
+  }
+}

src/main/scala/com/twitter/querulous/database/AutoDisablingDatabase.scala

@@ -0,0 +1,35 @@
+package com.twitter.querulous.database
+
+import com.twitter.xrayspecs.Duration
+import com.twitter.xrayspecs.TimeConversions._
+import java.sql.{Connection, SQLException, SQLIntegrityConstraintViolationException}
+
+
+class AutoDisablingDatabaseFactory(databaseFactory: DatabaseFactory, disableErrorCount: Int, disableDuration: Duration) extends DatabaseFactory {
+  def apply(dbhosts: List[String], dbname: String, username: String, password: String) = {
+    new AutoDisablingDatabase(databaseFactory(dbhosts, dbname, username, password), disableErrorCount, disableDuration)
+  }
+
+  def apply(dbhosts: List[String], username: String, password: String) = {
+    new AutoDisablingDatabase(databaseFactory(dbhosts, username, password), disableErrorCount, disableDuration)
+  }
+}
+
+class AutoDisablingDatabase(database: Database, protected val disableErrorCount: Int, protected val disableDuration: Duration) extends Database with AutoDisabler {
+  def open() = {
+    throwIfDisabled()
+    try {
+      val rv = database.open()
+      noteOperationOutcome(true)
+      rv
+    } catch {
+      case e: SQLException =>
+        noteOperationOutcome(false)
+        throw e
+      case e: Exception =>
+        throw e
+    }
+  }
+
+  def close(connection: Connection) { database.close(connection) }
+}

src/main/scala/com/twitter/querulous/evaluator/AutoDisablingQueryEvaluator.scala

@@ -27,10 +27,10 @@ class AutoDisablingQueryEvaluatorFactory(
   }
 }
 
-class AutoDisablingQueryEvaluator(
+class AutoDisablingQueryEvaluator (
   queryEvaluator: QueryEvaluator,
-  disableErrorCount: Int,
-  disableDuration: Duration) extends QueryEvaluatorProxy(queryEvaluator) {
+  protected val disableErrorCount: Int,
+  protected val disableDuration: Duration) extends QueryEvaluatorProxy(queryEvaluator) with AutoDisabler {
 
   private var disabledUntil: Time = Time.never
   private var consecutiveErrors = 0
@@ -56,24 +56,4 @@ class AutoDisablingQueryEvaluator(
     }
   }
 
-  private def noteOperationOutcome(success: Boolean) {
-    synchronized {
-      if (success) {
-        consecutiveErrors = 0
-      } else {
-        consecutiveErrors += 1
-        if (consecutiveErrors >= disableErrorCount) {
-          disabledUntil = disableDuration.fromNow
-        }
-      }
-    }
-  }
-
-  private def throwIfDisabled() {
-    synchronized {
-      if (Time.now < disabledUntil) {
-        throw new SQLException("Server is temporarily disabled")
-      }
-    }
-  }
 }