From 510257fd8b8f3480bd28fb889fc86aade923b997 Mon Sep 17 00:00:00 2001
From: Adhityaa <c.adhityaa@gmail.com>
Date: Wed, 20 Jun 2018 09:19:39 +0530
Subject: [PATCH] api: retry database connection if it fails

Closes https://gitlab.com/commento/commento-ce/issues/52
---
 api/database_connect.go | 15 ++++++++++++++-
 api/main.go             |  2 +-
 api/testing.go          |  2 +-
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/api/database_connect.go b/api/database_connect.go
index 110763e..202b9bf 100644
--- a/api/database_connect.go
+++ b/api/database_connect.go
@@ -1,12 +1,13 @@
 package main
 
 import (
+	"time"
 	"database/sql"
 	_ "github.com/lib/pq"
 	"os"
 )
 
-func connectDB() error {
+func connectDB(retriesLeft int) error {
 	con := os.Getenv("POSTGRES")
 	logger.Infof("opening connection to postgres: %s", con)
 
@@ -17,6 +18,18 @@ func connectDB() error {
 		return err
 	}
 
+	err = db.Ping()
+	if err != nil {
+		if retriesLeft > 0 {
+			logger.Errorf("cannot talk to postgres, retrying in 10 seconds (%d attempts left): %v", retriesLeft-1, err)
+			time.Sleep(10 * time.Second)
+			return connectDB(retriesLeft - 1)
+		} else {
+			logger.Errorf("cannot talk to postgres, last attempt failed: %v", err)
+			return err
+		}
+	}
+
 	statement := `
     CREATE TABLE IF NOT EXISTS migrations (
       filename TEXT NOT NULL UNIQUE
diff --git a/api/main.go b/api/main.go
index 703d621..08d5008 100644
--- a/api/main.go
+++ b/api/main.go
@@ -3,7 +3,7 @@ package main
 func main() {
 	exitIfError(createLogger())
 	exitIfError(parseConfig())
-	exitIfError(connectDB())
+	exitIfError(connectDB(5))
 	exitIfError(performMigrations())
 	exitIfError(smtpConfigure())
 	exitIfError(smtpTemplatesLoad())
diff --git a/api/testing.go b/api/testing.go
index 881d2a2..7f7c13d 100644
--- a/api/testing.go
+++ b/api/testing.go
@@ -68,7 +68,7 @@ func setupTestDatabase() error {
 		os.Setenv("POSTGRES", "postgres://postgres:postgres@localhost/commento_test?sslmode=disable")
 	}
 
-	if err := connectDB(); err != nil {
+	if err := connectDB(0); err != nil {
 		return err
 	}