ConnectMongoDB connect to mongodb with dsn.

ConnectRedis connect to redis with dsn.

ConnectSQLDatabase connect to sql database with dsn.

InitMongoDB return mongo db read & write instance from environment: MONGODB_HOST_WRITE, MONGODB_HOST_READ if want to create single connection, use MONGODB_HOST_WRITE and set empty for MONGODB_HOST_READ.

InitRedis connection from environment: REDIS_READ_DSN, REDIS_WRITE_DSN if want to create single connection, use REDIS_WRITE_DSN and set empty for REDIS_READ_DSN.

InitSQLDatabase return sql db read & write instance from environment: SQL_DB_READ_DSN, SQL_DB_WRITE_DSN if want to create single connection, use SQL_DB_WRITE_DSN and set empty for SQL_DB_READ_DSN.

ParseSQLDSN parse sql dsn.