This implementation is similar to AMQP notifications:
* Notifications are published on a single topic as a JSON feed
* Topic is configurable, as is the QoS. Uses the paho.mqtt.golang
library for the mqtt connection, and supports connections over tcp
and websockets, with optional secure tls support.
* Additionally the minio server configuration has been bumped up
so mqtt configuration can be added.
* Configuration migration code is added with tests.
MQTT is an ISO standard M2M/IoT messaging protocol and was
originally designed for applications for limited bandwidth
networks. Today it's use is growing in the IoT space.
Current code allowed it wrongly to generate secret key upto 100
we should only use 100 as a value to validate but for generating
it should be 40.
Fixes#4470
Previously serverConfigV17 used a global lock that made any instance of
serverConfigV17 depended on single global serverConfigMu.
This patch fixes by having individual lock per instances.
* Add configuration parameter "format" for db targets and perform
configuration migration.
* Add PostgreSQL `access` format: This causes Minio to append all events
to the configured table. Prefix, suffix and event filters continue
to be supported for this mode too.
* Update documentation for PostgreSQL notification target.
* Add MySQL `access` format: It is very similar to the same format for
PostgreSQL.
* Update MySQL notification documentation.
This patch fixes below
* Previously fatalIf() never writes log other than first logging target.
* quiet flag is not honored to show progress messages other than startup messages.
* Removes console package usage for progress messages.
As a new configuration parameter is added, configuration version is
bumped up from 14 to 15.
The MySQL target's behaviour is identical to the PostgreSQL: rows are
deleted from the MySQL table on delete-object events, and are
created/updated on create/over-write events.
