adding nrpgx5 instrumentation tracer for github.com/jackc/pgx/v5

[egon12]

This PR are adding instrumentation for nrpgx/v5 (https://github.com/jackc/pgx)

Links

The discussion about new tracing in pgx jackc/pgx#1061.
Open Telemetry Implementation for this tracing feature https://github.com/exaring/otelpgx/blob/main/tracer.go

Details

The pgx library has new tracing support in v5. Before pgx only support for logging that only provide us with duration of the operation. With this new tracing feature, we can create new Segment at QueryStart and End the Segment with QueryEnd

For passing the segment between QueryStart and QueryEnd we use context.Context. This folllow the implementation from open telemetry.

And for the Host, Port and Database Name, I try to follow database/sql implementation in nrpq and nrpgx by using BaseSegment.

To use the library you can use this code

cfg, _ := pgx.ParseConfig(context.Backgroud(), "<url here>")
cfg.Tracer = nrpgx5.NewTracer()

pgx.ConnectConfig(context.Background(), cfg)

[iamemilio]

Hi @egon12, thanks for contributing. Could you please include a simple example of how to use this library in a directory named example/.

[iamemilio]

I am not sure at which point in this extension we should be incorporating the go-agent

[egon12]

Just for info, this is related for this issues #386.
But In pgx/v4, we don't have tracer interface yet. So it's hard to add instrumentation.
In pgx/v5, the maintainer add tracer interface. And we can use that to add newrelic instrumentation

[egon12]

Hello are there any update on this?

[iamemilio]

Looks good to me, thanks for submitting this. Once you address the comment I left, you have my approval!

UPDATE: I went ahead and patched this up, since we are planning a release tomorrow. Thanks for submitting this, it should be live in the v3.20.1 release by EOD tomorrow :)

[BertBR]

There's any equivalent implementation for v4?