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.

AUTHOR

    Tom Molesworth <TEAM@cpan.org>

LICENSE

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

