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NAME

Net::Async::OpenTracing - OpenTracing APM via IO::Async

SYNOPSIS

 use Net::Async::OpenTracing;
 use IO::Async::Loop;
 use OpenTracing::Any qw($tracer);
 my $loop = IO::Async::Loop->new;
 $loop->add(
    my $tracing = Net::Async::OpenTracing->new(
        host => '127.0.0.1',
        port => 6832,
    )
 );
 $tracer->span(operation_name => 'example');
 # Manual sync - generally only needed on exit
 $tracing->sync->get;

DESCRIPTION

This all relies on the abstract OpenTracing interface, so that'd be the first port of call for official documentation.

Setting up and testing

If you want to experiment with this, start by setting up a Jæger instance in Docker like so:

 docker run -d --name jaeger \
  -e COLLECTOR_ZIPKIN_HTTP_PORT=9411 \
  -p 5775:5775/udp \
  -p 6831:6831/udp \
  -p 6832:6832/udp \
  -p 5778:5778 \
  -p 16686:16686 \
  -p 14268:14268 \
  -p 9411:9411 \
  jaegertracing/all-in-one:1.17

If you have a Kubernetes stack installed then you likely already have this available.

UDP port 6832 is typically the "binary Thrift" port, so that's likely where you would want this module configured to send data (other ports and protocols are available).

Set up an Net::Async::OpenTracing instance with those connection details:

 use Net::Async::OpenTracing;
 my $loop = IO::Async::Loop->new;
 $loop->add(
    my $tracing = Net::Async::OpenTracing->new(
        host => '127.0.0.1',
        port => 6832,
    )
 );
 # Now generate some traffic
 {
  my $span = $tracer->span(
   operation_name => 'example_span'
  );
  $span->log('test message ' . $_ . ' from the parent') for 1..3;
  my $child = $span->span(operation_name => 'child_span');
  $child->log('message ' . $_ . ' from the child span') for 1..3;
 }
 # Make sure all trace data is sent
 $tracing->sync->get;

You should then see a trace with 2 spans show up.

configure

Takes the following named parameters:

  • host - where to send traces

  • port - the UDP/TCP port to connect to

  • protocol - how to communicate: thrift, http/thrift, etc.

  • items_per_batch - number of spans to try sending each time

  • batches_per_loop - number of batches to try sending for each loop iteration

  • tracer - the OpenTracing::Tracer instance to use, defaults to the one provided by OpenTracing::Any

host

The hostname or IP to send spans to.

port

The port to send spans to.

tracer

The OpenTracing::Tracer instance, defaults to the standard OpenTracing::Any-provided one.

METHODS - Internal

send

Performs the send and sets up the Future for marking completion.

send_in_progress

Returns a Future indicating whether a send is in progress or not (will be marked as "done" in Future if the send is complete).

is_sending

Returns true if we are currently sending data.

start_sending

Trigger the send process, which will cause all pending traces to be sent to the remote endpoint.

Does nothing if sending is already in progress.

proto

The OpenTracing::Protocol instance.

sub

Sends all pending batches.

sub

Gathers and sends a single OpenTracing::Batch.

span_completion

Our callback for reporting span completion.

udp

The remote UDP endpoint (if it exists).

sync

Ensure that we've sent any remaining traces. Can be called just before shutdown to clear off any pending items - this returns a Future, so you'd want code similar to

 $tracing->sync->get;

to ensure that it completes before returning.

INHERITED METHODS

IO::Async::Notifier

add_child, adopt_future, adopted_futures, can_event, children, configure_unknown, debug_printf, get_loop, invoke_error, invoke_event, loop, make_event_cb, maybe_invoke_event, maybe_make_event_cb, new, notifier_name, parent, remove_child, remove_from_parent

AUTHOR

Tom Molesworth <TEAM@cpan.org>

LICENSE

Copyright Tom Molesworth 2018-2020. Licensed under the same terms as Perl itself.