[DSM] Fix an issue where RabbitMQ producers when producing a message to the default exchange were setting checkpoints that didn't work in DSM

[ericfirth]

What does this PR do?

The RabbitMQ DSM integration is built with the idea that users will always have an exchange. The Producer plugin sends a checkpoint with the exchange (and no topic). However, there is an API in RabbitMQ where instead of publishing to an exchange w/ a routing key, you send either directly to a queue or you publish to either an undefined or empty string exchange and then the routing key is the queue and the exchange is the default exchange (link, see second sentence of the first bullet). In this case we are unable to show the connection between producer and consumer because we are only sending a checkpoint w/ the exchange which is blank and then the consumer has the topic and the exchange (still blank) and thus we aren't able to correlate them. This is happening w/ a client (unnamed)

see:
debug endpoint w/ checkpoints

trace on producer where we can see that the producer is sending only a routingKey and not an exchange

what the map ends up looking like

To test that this works, I made an experiment using this branch of the tracer on staging w/ the data-streams-dev and sent a message from the producer w/ no exchange. you can see that here

why conditionally send the topic? why not always send the topic?

This fix is for only this case, in a case where we have an exchange, we still want to correlate via the exchange and get the difference between the queue and the routing key (so we only send the topic on the producer if there is a routing key and an empty exchange), otherwise we'd have a connection between two services that looked like this:

Motivation

Plugin Checklist

• Unit tests.
• TypeScript definitions.
• TypeScript tests.
• API documentation.
• CircleCI jobs/workflows.
• Plugin is exported.

Additional Notes

[github-actions]

Overall package size

Self size: 8.54 MB
Deduped: 94.94 MB
No deduping: 95.45 MB

Dependency sizes

| name | version | self size | total size | |------|---------|-----------|------------| | @datadog/libdatadog | 0.4.0 | 29.44 MB | 29.44 MB | | @datadog/native-appsec | 8.4.0 | 19.25 MB | 19.26 MB | | @datadog/native-iast-taint-tracking | 3.2.0 | 13.9 MB | 13.91 MB | | @datadog/pprof | 5.5.0 | 9.8 MB | 10.17 MB | | protobufjs | 7.2.5 | 2.77 MB | 5.16 MB | | @datadog/native-iast-rewriter | 2.6.1 | 2.59 MB | 2.73 MB | | @opentelemetry/core | 1.14.0 | 872.87 kB | 1.47 MB | | @datadog/native-metrics | 3.1.0 | 1.06 MB | 1.46 MB | | @opentelemetry/api | 1.8.0 | 1.21 MB | 1.21 MB | | import-in-the-middle | 1.11.2 | 112.74 kB | 826.22 kB | | source-map | 0.7.4 | 226 kB | 226 kB | | opentracing | 0.14.7 | 194.81 kB | 194.81 kB | | lru-cache | 7.18.3 | 133.92 kB | 133.92 kB | | pprof-format | 2.1.0 | 111.69 kB | 111.69 kB | | @datadog/sketches-js | 2.1.0 | 109.9 kB | 109.9 kB | | semver | 7.6.3 | 95.82 kB | 95.82 kB | | lodash.sortby | 4.7.0 | 75.76 kB | 75.76 kB | | ignore | 5.3.1 | 51.46 kB | 51.46 kB | | shell-quote | 1.8.1 | 44.96 kB | 44.96 kB | | istanbul-lib-coverage | 3.2.0 | 29.34 kB | 29.34 kB | | rfdc | 1.3.1 | 25.21 kB | 25.21 kB | | @isaacs/ttlcache | 1.4.1 | 25.2 kB | 25.2 kB | | tlhunter-sorted-set | 0.1.0 | 24.94 kB | 24.94 kB | | limiter | 1.1.5 | 23.17 kB | 23.17 kB | | dc-polyfill | 0.1.4 | 23.1 kB | 23.1 kB | | retry | 0.13.1 | 18.85 kB | 18.85 kB | | jest-docblock | 29.7.0 | 8.99 kB | 12.76 kB | | crypto-randomuuid | 1.0.0 | 11.18 kB | 11.18 kB | | ttl-set | 1.0.0 | 4.61 kB | 9.69 kB | | path-to-regexp | 0.1.12 | 6.6 kB | 6.6 kB | | koalas | 1.0.2 | 6.47 kB | 6.47 kB | | module-details-from-path | 1.0.3 | 4.47 kB | 4.47 kB |

_{🤖 This report was automatically generated by heaviest-objects-in-the-universe}

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-01-24 15:08:34

Comparing candidate commit 91473d1 in PR branch eric.firth/fix-bug-on-dsm-with-rabbitmq with baseline commit c13d368 in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 912 metrics, 21 unstable metrics.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.05%. Comparing base (4f22cf7) to head (8c6cfe7).
Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #5150   +/-   ##
=======================================
  Coverage   81.05%   81.05%           
=======================================
  Files         477      477           
  Lines       21307    21308    +1     
=======================================
+ Hits        17270    17271    +1     
  Misses       4037     4037           

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[wconti27]

LGTM!