ping method analog

[vtolstov]

database/sql has ping method to understand that driver connected to database instance
does it possible to force connect Client to broker and get some results ? Mostly for me this is needed to check that broker address properly set and broker available.

[twmb]

Issue an ApiVersions request. Pinging goes against the client internally not connecting unless necessary.

[vtolstov]

thanks

[twmb]

As an example: https://github.com/cloudhut/kowl/blob/24b84448e87cb8fc8d16eebf405a0d1b694d27ff/backend/pkg/kafka/service.go#L132-L165

[vtolstov]

Wow, nice. Thank you

[twmb]

I'm thinking to add this, after a few more requests.

[weeco]

What would the ping method do? Just an ApiVersions request (which would also be valid without authentication) or also a metadata request for instance? Would that be part of the admin client or what's the idea?

[twmb]

I'm thinking:

// Ping returns whether any broker is reachable, iterating over any discovered broker
// or seed broker until one returns a successful response to an ApiVersions request.
// Each request is retried up to 3 times depending on the how the request fails.
// If all requests fail, this returns final error.
func (cl *Client) Ping() error

type PingBrokerError struct {
        Broker BrokerMetadata
        Err    error
}
type PingBrokerErrors []PingBrokerError


// Any returns the first error, if any.
func (es PingBrokerErrors) Any() error

// PingAll iterates through all discovered brokers and issues an ApiVersions request
// to each to test broker connectivity. If there are currently no discovered brokers,
// this iterates through all seed brokers.
func (cl *Client) PingAll() PingBrokerErrors

I'm not yet settled on the API for PingAll: should always iterate over both seeds and non-seeds?

[vtolstov]

I'm prefer to have Ping(context.Context) error method.
So i can set deadline on context

[twmb]

I've added Ping(context.Context) error, good suggestion about deadlining. This has now been tagged in v1.3.0.