Merge pull request #151 from iegomez/fix/add-db-ping-retries

Add connect_tries option for DB backends.

README.md

@@ -499,20 +499,21 @@ The `postgres` backend allows to specify queries for user, superuser and acl ch
 
 The following `auth_opt_` options are supported:
 
-| Option | default | Mandatory | Meaning |
-| -------------- | ----------------- | :---------: | ------------------------ |
-| pg_host | localhost | | hostname/address
-| pg_port | 5432 | | TCP port
-| pg_user | | Y | username
-| pg_password | | Y | password
-| pg_dbname | | Y | database name
-| pg_userquery | | Y | SQL for users
-| pg_superquery | | N | SQL for superusers
-| pg_aclquery | | N | SQL for ACLs
-| pg_sslmode | disable | N | SSL/TLS mode.
-| pg_sslcert | | N | SSL/TLS Client Cert.
-| pg_sslkey | | N | SSL/TLS Client Cert. Key
-| pg_sslrootcert | | N | SSL/TLS Root Cert
+| Option | default | Mandatory | Meaning |
+| --------------------- | ----------------- | :---------: | ----------------------------------------------------------- |
+| pg_host | localhost | | hostname/address |
+| pg_port | 5432 | | TCP port |
+| pg_user | | Y | username |
+| pg_password | | Y | password |
+| pg_dbname | | Y | database name |
+| pg_userquery | | Y | SQL for users |
+| pg_superquery | | N | SQL for superusers |
+| pg_aclquery | | N | SQL for ACLs |
+| pg_sslmode | disable | N | SSL/TLS mode. |
+| pg_sslcert | | N | SSL/TLS Client Cert. |
+| 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 |
 
 Depending on the sslmode given, sslcert, sslkey and sslrootcert will be used. Options for sslmode are:
 
@@ -569,12 +570,18 @@ auth_opt_pg_port 5432
 auth_opt_pg_dbname appserver
 auth_opt_pg_user appserver
 auth_opt_pg_password appserver
+auth_opt_pg_connect_tries 5
 auth_opt_pg_userquery select password_hash from "user" where username = $1 and is_active = true limit 1
 auth_opt_pg_superquery select count(*) from "user" where username = $1 and is_admin = true
 auth_opt_pg_aclquery select distinct 'application/' || a.id || '/#' from "user" u inner join organization_user ou on ou.user_id = u.id inner join organization o on o.id = ou.organization_id inner join application a on a.organization_id = o.id where u.username = $1 and $2 = $2
 
 ```
 
+**DB connect tries**: on startup, depending on `pg_connect_tries` option, the plugin will try to connect and ping the DB a max number of times or forever every 2 seconds.
+By default it will try to reconnect forever to maintain backwards compatibility and avoid issues when `mosquitto` starts before the DB service does, 
+but you may choose to ping a max amount of times by setting any positive number. 
+If given 0, the DB will try to connect only once, which would be the same as setting the option to 1.
+
 #### Password hashing
 
 For instructions on how to set a backend specific hasher or use the general one, see [Hashing](#hashing).
@@ -635,22 +642,23 @@ auth_opt_mysql_allow_native_passwords true
 
 Supported options for `mysql` are:
 
-| Option | default | Mandatory | Meaning |
-| -------------- | ----------------- | :---------: | ------------------------ |
-| mysql_host | localhost | N | hostname/address
-| mysql_port | 3306 | N | TCP port
-| mysql_user | | Y | username
-| mysql_password | | Y | password
-| mysql_dbname | | Y | database name
-| mysql_userquery | | Y | SQL for users
-| mysql_superquery | | N | SQL for superusers
-| mysql_aclquery | | N | SQL for ACLs
-| mysql_sslmode | disable | N | SSL/TLS mode.
-| mysql_sslcert | | N | SSL/TLS Client Cert.
-| mysql_sslkey | | N | SSL/TLS Client Cert. Key
-| mysql_sslrootcert | | N | SSL/TLS Root Cert
-| mysql_protocol | tcp | N | Connection protocol
-| mysql_socket | | N | Unix socket path
+| Option | default | Mandatory | Meaning |
+| ------------------------- | ----------------- | :---------: | ----------------------------------------------------------- |
+| mysql_host | localhost | N | hostname/address |
+| mysql_port | 3306 | N | TCP port |
+| mysql_user | | Y | username |
+| mysql_password | | Y | password |
+| mysql_dbname | | Y | database name |
+| mysql_userquery | | Y | SQL for users |
+| mysql_superquery | | N | SQL for superusers |
+| mysql_aclquery | | N | SQL for ACLs |
+| mysql_sslmode | disable | N | SSL/TLS mode. |
+| mysql_sslcert | | N | SSL/TLS Client Cert. |
+| mysql_sslkey | | N | SSL/TLS Client Cert. Key |
+| mysql_sslrootcert | | N | SSL/TLS Root Cert |
+| 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 |
 
 
 Finally, placeholders for mysql differ from those of postgres, changing from $1, $2, etc., to simply ?. These are some **example** queries for `mysql`:
@@ -674,6 +682,11 @@ Acl query:
 SELECT topic FROM acl WHERE (username = ?) AND rw = ?
 ```
 
+**DB connect tries**: on startup, depending on `mysql_connect_tries` option, the plugin will try to connect and ping the DB a max number of times or forever every 2 seconds.
+By default it will try to reconnect forever to maintain backwards compatibility and avoid issues when `mosquitto` starts before the DB service does, 
+but you may choose to ping a max amount of times by setting any positive number. 
+If given 0, the DB will try to connect only once, which would be the same as setting the option to 1.
+
 #### Password hashing
 
 For instructions on how to set a backend specific hasher or use the general one, see [Hashing](#hashing).
@@ -720,12 +733,13 @@ ON UPDATE CASCADE
 The `sqlite` backend works in the same way as `postgres` and `mysql` do, except that being a light weight db, it has fewer configuration options.
 The following `auth_opt_` options are supported:
 
-| Option | default | Mandatory | Meaning |
-| --------------------- | ----------------- | :---------: | ------------------------ |
-| sqlite_source | | Y | SQLite3 source
-| sqlite_userquery | | Y | SQL for users
-| sqlite_superquery | | N | SQL for superusers
-| sqlite_aclquery | | N | SQL for ACLs
+| Option | default | Mandatory | Meaning |
+| ------------------------- | ----------------- | :---------: | ----------------------------------------------------------- |
+| sqlite_source | | Y | SQLite3 source |
+| sqlite_userquery | | Y | SQL for users |
+| 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 |
 
 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.
 
@@ -745,6 +759,11 @@ sqlite_superquery SELECT COUNT(*) FROM account WHERE username = ? AND super = 1
 sqlite_aclquery SELECT topic FROM acl WHERE (username = ?) AND rw >= ?
 ```
 
+**DB connect tries**: on startup, depending on `sqlite_connect_tries` option, the plugin will try to connect and ping the DB a max number of times or forever every 2 seconds.
+By default it will try to reconnect forever to maintain backwards compatibility and avoid issues when `mosquitto` starts before the DB service does, 
+but you may choose to ping a max amount of times by setting any positive number. 
+If given 0, the DB will try to connect only once, which would be the same as setting the option to 1.
+
 #### Password hashing
 
 For instructions on how to set a backend specific hasher or use the general one, see [Hashing](#hashing).

backends/db.go

@@ -1,6 +1,7 @@
 package backends
 
 import (
+ "fmt"
  "time"
 
  "github.com/jmoiron/sqlx"
@@ -11,20 +12,33 @@ 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) (*sqlx.DB, error) {
+func OpenDatabase(dsn, engine string, tries int) (*sqlx.DB, error) {
 
  db, err := sqlx.Open(engine, dsn)
  if err != nil {
  return nil, errors.Wrap(err, "database connection error")
  }
 
- for {
+ if tries == 0 {
+ tries = 1
+ }
+
+ for tries != 0 {
  if err = db.Ping(); err != nil {
- log.Errorf("ping database error, will retry in 2s: %s", err)
+ log.Errorf("ping database %s error, will retry in 2s: %s", engine, err)
  time.Sleep(2 * time.Second)
  } else {
  break
  }
+
+ if tries > 0 {
+ tries--
+ }
+ }
+
+ // Return last ping error when done trying.
+ if tries == 0 {
+ return nil, fmt.Errorf("couldn't ping database %s: %s", engine, err)
  }
 
  return db, nil

backends/mysql.go

@@ -6,6 +6,7 @@ import (
  "database/sql"
  "fmt"
  "io/ioutil"
+ "strconv"
  "strings"
 
  mq "github.com/go-sql-driver/mysql"
@@ -34,6 +35,8 @@ type Mysql struct {
  SocketPath string
  AllowNativePasswords bool
  hasher hashing.HashComparer
+
+ connectTries int
 }
 
 func NewMysql(authOpts map[string]string, logLevel log.Level, hasher hashing.HashComparer) (Mysql, error) {
@@ -190,8 +193,18 @@ func NewMysql(authOpts map[string]string, logLevel log.Level, hasher hashing.Has
  }
  }
 
+ if tries, ok := authOpts["mysql_connect_tries"]; ok {
+ connectTries, err := strconv.Atoi(tries)
+
+ if err != nil {
+ log.Warnf("invalid mysql connect tries options: %s", err)
+ } else {
+ mysql.connectTries = connectTries
+ }
+ }
+
  var err error
- mysql.DB, err = OpenDatabase(msConfig.FormatDSN(), "mysql")
+ mysql.DB, err = OpenDatabase(msConfig.FormatDSN(), "mysql", mysql.connectTries)
 
  if err != nil {
  return mysql, errors.Errorf("MySql backend error: couldn't open db: %s", err)

backends/postgres.go

@@ -3,6 +3,7 @@ package backends
 import (
  "database/sql"
  "fmt"
+ "strconv"
  "strings"
 
  "github.com/iegomez/mosquitto-go-auth/hashing"
@@ -28,6 +29,8 @@ type Postgres struct {
  SSLKey string
  SSLRootCert string
  hasher hashing.HashComparer
+
+ connectTries int
 }
 
 func NewPostgres(authOpts map[string]string, logLevel log.Level, hasher hashing.HashComparer) (Postgres, error) {
@@ -46,6 +49,7 @@ func NewPostgres(authOpts map[string]string, logLevel log.Level, hasher hashing.
  SuperuserQuery: "",
  AclQuery: "",
  hasher: hasher,
+ connectTries: -1,
  }
 
  if host, ok := authOpts["pg_host"]; ok {
@@ -134,8 +138,18 @@ func NewPostgres(authOpts map[string]string, logLevel log.Level, hasher hashing.
  connStr = fmt.Sprintf("%s sslmode=disable", connStr)
  }
 
+ if tries, ok := authOpts["pg_connect_tries"]; ok {
+ connectTries, err := strconv.Atoi(tries)
+
+ if err != nil {
+ log.Warnf("invalid postgres connect tries options: %s", err)
+ } else {
+ postgres.connectTries = connectTries
+ }
+ }
+
  var err error
- postgres.DB, err = OpenDatabase(connStr, "postgres")
+ postgres.DB, err = OpenDatabase(connStr, "postgres", postgres.connectTries)
 
  if err != nil {
  return postgres, errors.Errorf("PG backend error: couldn't open db: %s", err)

backends/sqlite.go

@@ -2,6 +2,7 @@ package backends
 
 import (
  "database/sql"
+ "strconv"
  "strings"
 
  "github.com/iegomez/mosquitto-go-auth/hashing"
@@ -19,6 +20,8 @@ type Sqlite struct {
  SuperuserQuery string
  AclQuery string
  hasher hashing.HashComparer
+
+ connectTries int
 }
 
 func NewSqlite(authOpts map[string]string, logLevel log.Level, hasher hashing.HashComparer) (Sqlite, error) {
@@ -69,8 +72,18 @@ func NewSqlite(authOpts map[string]string, logLevel log.Level, hasher hashing.Ha
  connStr = sqlite.Source
  }
 
+ if tries, ok := authOpts["sqlite_connect_tries"]; ok {
+ connectTries, err := strconv.Atoi(tries)
+
+ if err != nil {
+ log.Warnf("invalid sqlite connect tries options: %s", err)
+ } else {
+ sqlite.connectTries = connectTries
+ }
+ }
+
  var err error
- sqlite.DB, err = OpenDatabase(connStr, "sqlite3")
+ sqlite.DB, err = OpenDatabase(connStr, "sqlite3", sqlite.connectTries)
 
  if err != nil {
  return sqlite, errors.Errorf("sqlite backend error: couldn't open db %s: %s", connStr, err)