Add option to set DB connection max life time in seconds and document it.

README.md

@@ -599,6 +599,7 @@ The following `auth_opt_` options are supported:
 | pg_sslkey         	|                   |     N       | SSL/TLS Client Cert. Key	 								|
 | pg_sslrootcert    	|                   |     N       | SSL/TLS Root Cert			 								|
 | pg_connect_tries    	|        -1         |     N       | x < 0: try forever, x > 0: try x times						|
+| pg_max_life_time      |                   |     N       | connection max life time in seconds                         |
 
 Depending on the sslmode given, sslcert, sslkey and sslrootcert will be used. Options for sslmode are:
 
@@ -744,6 +745,7 @@ Supported options for `mysql` are:
 | mysql_protocol        	|       tcp         |     N       | Connection protocol											|
 | mysql_socket          	|                   |     N       | Unix socket path											|
 | mysql_connect_tries    	|        -1         |     N       | x < 0: try forever, x > 0: try x times						|
+| mysql_max_life_time       |                   |     N       | connection max life time on seconds                         |
 
 
 Finally, placeholders for mysql differ from those of postgres, changing from $1, $2, etc., to simply ?. These are some **example** queries for `mysql`:
@@ -825,6 +827,7 @@ The following `auth_opt_` options are supported:
 | sqlite_superquery     	|                   |     N       | SQL for superusers											|
 | sqlite_aclquery       	|                   |     N       | SQL for ACLs												|
 | sqlite_connect_tries	    |        -1         |     N       | x < 0: try forever, x > 0: try x times						|
+| sqlite_max_life_time      |                   |     N       | connection max life time in seconds                         |
 
 SQLite3 allows to connect to an in-memory db, or a single file one, so source maybe `memory` (not :memory:) or the path to a file db.
 

backends/db.go

@@ -12,7 +12,7 @@ import (
 // OpenDatabase opens the database and performs a ping to make sure the
 // database is up.
 // Taken from brocaar's lora-app-server: https://github.com/brocaar/lora-app-server
-func OpenDatabase(dsn, engine string, tries int) (*sqlx.DB, error) {
+func OpenDatabase(dsn, engine string, tries int, maxLifeTime int64) (*sqlx.DB, error) {
 
 	db, err := sqlx.Open(engine, dsn)
 	if err != nil {
@@ -41,7 +41,9 @@ func OpenDatabase(dsn, engine string, tries int) (*sqlx.DB, error) {
 		return nil, fmt.Errorf("couldn't ping database %s: %s", engine, err)
 	}
 
-	db.SetConnMaxLifetime(time.Minute)
+	if maxLifeTime > 0 {
+		db.SetConnMaxLifetime(time.Duration(maxLifeTime) * time.Second)
+	}
 
 	return db, nil
 }

backends/mysql.go

@@ -36,6 +36,7 @@ type Mysql struct {
 	SocketPath           string
 	AllowNativePasswords bool
 	hasher               hashing.HashComparer
+	maxLifeTime          int64
 
 	connectTries int
 }
@@ -204,8 +205,16 @@ func NewMysql(authOpts map[string]string, logLevel log.Level, hasher hashing.Has
 		}
 	}
 
+	if maxLifeTime, ok := authOpts["mysql_max_life_time"]; ok {
+		lifeTime, err := strconv.ParseInt(maxLifeTime, 10, 64)
+
+		if err == nil {
+			mysql.maxLifeTime = lifeTime
+		}
+	}
+
 	var err error
-	mysql.DB, err = OpenDatabase(msConfig.FormatDSN(), "mysql", mysql.connectTries)
+	mysql.DB, err = OpenDatabase(msConfig.FormatDSN(), "mysql", mysql.connectTries, mysql.maxLifeTime)
 
 	if err != nil {
 		return mysql, errors.Errorf("MySql backend error: couldn't open db: %s", err)

backends/postgres.go

@@ -30,6 +30,7 @@ type Postgres struct {
 	SSLKey         string
 	SSLRootCert    string
 	hasher         hashing.HashComparer
+	maxLifeTime    int64
 
 	connectTries int
 }
@@ -149,8 +150,16 @@ func NewPostgres(authOpts map[string]string, logLevel log.Level, hasher hashing.
 		}
 	}
 
+	if maxLifeTime, ok := authOpts["pg_max_life_time"]; ok {
+		lifeTime, err := strconv.ParseInt(maxLifeTime, 10, 64)
+
+		if err == nil {
+			postgres.maxLifeTime = lifeTime
+		}
+	}
+
 	var err error
-	postgres.DB, err = OpenDatabase(connStr, "postgres", postgres.connectTries)
+	postgres.DB, err = OpenDatabase(connStr, "postgres", postgres.connectTries, postgres.maxLifeTime)
 
 	if err != nil {
 		return postgres, errors.Errorf("PG backend error: couldn't open db: %s", err)

backends/sqlite.go

@@ -21,6 +21,7 @@ type Sqlite struct {
 	SuperuserQuery string
 	AclQuery       string
 	hasher         hashing.HashComparer
+	maxLifeTime    int64
 
 	connectTries int
 }
@@ -62,6 +63,14 @@ func NewSqlite(authOpts map[string]string, logLevel log.Level, hasher hashing.Ha
 		sqlite.AclQuery = aclQuery
 	}
 
+	if maxLifeTime, ok := authOpts["sqlite_max_life_time"]; ok {
+		lifeTime, err := strconv.ParseInt(maxLifeTime, 10, 64)
+
+		if err == nil {
+			sqlite.maxLifeTime = lifeTime
+		}
+	}
+
 	//Exit if any mandatory option is missing.
 	if !sqliteOk {
 		return sqlite, errors.Errorf("sqlite backend error: missing options: %s", missingOptions)
@@ -84,7 +93,7 @@ func NewSqlite(authOpts map[string]string, logLevel log.Level, hasher hashing.Ha
 	}
 
 	var err error
-	sqlite.DB, err = OpenDatabase(connStr, "sqlite3", sqlite.connectTries)
+	sqlite.DB, err = OpenDatabase(connStr, "sqlite3", sqlite.connectTries, sqlite.maxLifeTime)
 
 	if err != nil {
 		return sqlite, errors.Errorf("sqlite backend error: couldn't open db %s: %s", connStr, err)