* 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.
checkURL() is a generic function to check if a passed address
is valid. This commit adds support for addresses like `m1`
and `172.16.3.1` which is needed in MySQL and NATS. This commit
also adds tests.
This is an attempt cleanup code and keep the top level config
functions simpler and easy to understand where as move the
notifier related code and logger setter/getter methods as part
of their own struct.
Locks are now held properly not globally by configMutex, but
instead as private variables.
Final fix for #3700
ElasticSearch and Redis are both treated like a database.
Each indexs are based on the object names uniquely indentifying
the event. Upon each delete event of the named object deletes
the index on elasticsearch and redis respectively.
