Don't resolve container tags if already set

[dineshg13]

What does this PR do?

StatsWriter wouldn't resolve container Tags if the incoming payload already has tags associated with it.

Motivation

DD connector now adds tags from OTLP payload see open-telemetry/opentelemetry-collector-contrib#31642

Additional Notes

Possible Drawbacks / Trade-offs

Describe how to test/QA your changes

This change only impacts collector with DD connector. No QA necessary for agent

[ahmed-mez]

Looks good! Please add details to the PR description

• In the motivation: In which scenarios a stats payload can have container tags already resolved
• A QA plan

[knusbaum]

In the motivation: In which scenarios a stats payload can have container tags already resolved

+1. The description for this field is that it's specifically for container tags, and that it's not supposed to be set by the client. If we're not following that we should understand where/why and maybe change the documentation.

datadog-agent/pkg/proto/datadog/trace/stats.proto

Lines 45 to 47 in 11e8ea8

	// Tags specifies a set of tags obtained from the orchestrator (where applicable) using the specified containerID.
	// This field should be left empty by the client. It only applies to some specific environment.
	repeated string tags = 12;

Misunderstandings here could cause broken container tags or other problems.

[dineshg13]

@knusbaum @ahmed-mez updated the description

[pkalmakis]

Is there a scenario in the future where we would want to supply some of the container tags but still do a lookup and merge the two?

[dineshg13]

I don't see a scenario where we need to append Tags to already present ones.

[jdgumz]

It could happen that the container tags become stale?

Today we don't add container tags upstream in the concentrator or before it. But if we did, then by the time the stats come out (10 sec) perhaps the container tags mapping will have changed in some way?

We might need to change this code again once we properly support adding container tags upstream in the concentrator. But for right now I think this change is safe.

[ahmed-mez]

/trigger-ci --variable RUN_ALL_BUILDS=true --variable RUN_KITCHEN_TESTS=true --variable RUN_E2E_TESTS=on --variable RUN_UNIT_TESTS=on

[dd-devflow]

🚂 Gitlab pipeline started

Started pipeline #30347288

[pr-commenter]

Test changes on VM

Use this command from test-infra-definitions to manually test this PR changes on a VM:

inv create-vm --pipeline-id=30347288 --os-family=ubuntu

[pr-commenter]

Regression Detector

Regression Detector Results

Run ID: 79864cbd-d31e-4f45-b6d2-bac0e199a580
Baseline: 28545c5
Comparison: 991f5a8

Performance changes are noted in the perf column of each table:

• ✅ = significantly better comparison variant performance
• ❌ = significantly worse comparison variant performance
• ➖ = no significant change in performance

No significant changes in experiment optimization goals

Confidence level: 90.00%
Effect size tolerance: |Δ mean %| ≥ 5.00%

There were no significant changes in experiment optimization goals at this confidence level and effect size tolerance.

Experiments ignored for regressions

Regressions in experiments with settings containing erratic: true are ignored.

perf	experiment	goal	Δ mean %	Δ mean % CI
➖	file_to_blackhole	% cpu utilization	-1.85	[-8.14, +4.44]

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI
➖	pycheck_1000_100byte_tags	% cpu utilization	+2.80	[-2.16, +7.76]
➖	uds_dogstatsd_to_api_cpu	% cpu utilization	+1.26	[-1.52, +4.04]
➖	basic_py_check	% cpu utilization	+1.23	[-1.16, +3.62]
➖	tcp_syslog_to_blackhole	ingress throughput	+0.42	[+0.34, +0.51]
➖	process_agent_standard_check_with_stats	memory utilization	+0.35	[+0.32, +0.38]
➖	idle	memory utilization	+0.10	[+0.07, +0.13]
➖	trace_agent_json	ingress throughput	+0.03	[+0.00, +0.05]
➖	tcp_dd_logs_filter_exclude	ingress throughput	+0.01	[-0.02, +0.04]
➖	trace_agent_msgpack	ingress throughput	-0.00	[-0.00, +0.00]
➖	uds_dogstatsd_to_api	ingress throughput	-0.00	[-0.20, +0.20]
➖	otel_to_otel_logs	ingress throughput	-0.02	[-0.46, +0.43]
➖	process_agent_standard_check	memory utilization	-0.17	[-0.20, -0.14]
➖	file_tree	memory utilization	-0.32	[-0.42, -0.23]
➖	process_agent_real_time_mode	memory utilization	-0.39	[-0.42, -0.36]
➖	file_to_blackhole	% cpu utilization	-1.85	[-8.14, +4.44]

Explanation

A regression test is an A/B test of target performance in a repeatable rig, where "performance" is measured as "comparison variant minus baseline variant" for an optimization goal (e.g., ingress throughput). Due to intrinsic variability in measuring that goal, we can only estimate its mean value for each experiment; we report uncertainty in that value as a 90.00% confidence interval denoted "Δ mean % CI".

For each experiment, we decide whether a change in performance is a "regression" -- a change worth investigating further -- if all of the following criteria are true:

1. Its estimated |Δ mean %| ≥ 5.00%, indicating the change is big enough to merit a closer look.

2. Its 90.00% confidence interval "Δ mean % CI" does not contain zero, indicating that if our statistical model is accurate, there is at least a 90.00% chance there is a difference in performance between baseline and comparison variants.

3. Its configuration does not mark it "erratic".

[dineshg13]

/merge

[dd-devflow]

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