From 2c27a23d9ffd5f820dd3d2ad89f6cfc2954eb74f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kjetil=20Nyg=C3=A5rd?= <kny@ambita.com>
Date: Fri, 25 Nov 2016 21:56:19 +0100
Subject: [PATCH] Added parameter initalizationMaxAttempts which controls
 number of attempts to connect to the database. See issue 770:
 https://github.com/brettwooldridge/HikariCP/issues/770

---
 .../java/com/zaxxer/hikari/HikariConfig.java  | 20 ++++++++++++
 .../com/zaxxer/hikari/pool/HikariPool.java    | 31 +++++++++++++++----
 2 files changed, 45 insertions(+), 6 deletions(-)

diff --git a/src/main/java/com/zaxxer/hikari/HikariConfig.java b/src/main/java/com/zaxxer/hikari/HikariConfig.java
index 030ac24e7..639140fce 100644
--- a/src/main/java/com/zaxxer/hikari/HikariConfig.java
+++ b/src/main/java/com/zaxxer/hikari/HikariConfig.java
@@ -83,6 +83,7 @@ public class HikariConfig implements HikariConfigMXBean
    private boolean isAutoCommit;
    private boolean isReadOnly;
    private boolean isInitializationFailFast;
+   private long initializationMaxAttempts;
    private boolean isIsolateInternalQueries;
    private boolean isRegisterMbeans;
    private boolean isAllowPoolSuspension;
@@ -112,6 +113,7 @@ public HikariConfig()
 
       isAutoCommit = true;
       isInitializationFailFast = true;
+      initializationMaxAttempts = 1;
 
       String systemProp = System.getProperty("hikaricp.configurationFile");
       if (systemProp != null) {
@@ -415,6 +417,24 @@ public void setInitializationFailFast(boolean failFast)
       isInitializationFailFast = failFast;
    }
 
+   /**
+    * Get maximum number of connection attemts, that will be performed during startup.
+    *
+    * @return Number of attempts to get initail connection.
+    */
+   public long getInitializationMaxAttempts() {
+      return initializationMaxAttempts;
+   }
+
+   /**
+    * Set maximum number of connection attempts, that will be performed during startup.
+    *
+    * @param initializationMaxAttempts Maximum number of connection attempts during startup.
+    */
+   public void setInitializationMaxAttempts(long initializationMaxAttempts) {
+      this.initializationMaxAttempts = initializationMaxAttempts;
+   }
+
    public boolean isIsolateInternalQueries()
    {
       return isIsolateInternalQueries;
diff --git a/src/main/java/com/zaxxer/hikari/pool/HikariPool.java b/src/main/java/com/zaxxer/hikari/pool/HikariPool.java
index 46a3f0b9b..ef913c7d3 100644
--- a/src/main/java/com/zaxxer/hikari/pool/HikariPool.java
+++ b/src/main/java/com/zaxxer/hikari/pool/HikariPool.java
@@ -508,13 +508,22 @@ private void abortActiveConnections(final ExecutorService assassinExecutor)
    private void checkFailFast()
    {
       if (config.isInitializationFailFast()) {
-         try (Connection connection = newConnection()) {
-            if (!connection.getAutoCommit()) {
-               connection.commit();
+         for (int i = 0; i < config.getInitializationMaxAttempts(); i++) {
+            try (Connection connection = newConnection()) {
+               if (!connection.getAutoCommit()) {
+                  connection.commit();
+               }
+               return;
+            }
+            catch (Throwable e) {
+               if (i == config.getInitializationMaxAttempts() - 1) {
+                  throw new PoolInitializationException(e);
+               }
+               else {
+                  LOGGER.error("Error connecting during startup. Attempt #" + i);
+                  quietlySleep(100L);
+               }
             }
-         }
-         catch (Throwable e) {
-            throw new PoolInitializationException(e);
          }
       }
    }
@@ -665,5 +674,15 @@ public PoolInitializationException(Throwable t)
       {
          super("Failed to initialize pool: " + t.getMessage(), t);
       }
+
+      /**
+       * Construct an exception, with a message.
+       *
+       * @param message Exceptiion message
+       */
+      public PoolInitializationException(String message)
+      {
+         super(message);
+      }
    }
 }