Remove all use of model.NewConfig in test in favor of the mock

[hush-hush]

What does this PR do?

Remove all use of model.NewConfig in test in favor of the mock. This prevent tests creating multiple conflicting configurations.

This commit also add a linter to prevent more usage to be added.

Describe how to test/QA your changes

Running the CI is enough since we're only changing the tests.

[agent-platform-auto-pr]

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=46297687 --os-family=ubuntu

Note: This applies to commit f3e0455

[cit-pr-commenter]

Regression Detector

Regression Detector Results

Metrics dashboard
Target profiles
Run ID: bd3fa8ff-03b7-43c4-84c7-f88157adea92

Baseline: ad37c41
Comparison: f3e0455

Regression Detector: ❌

Bounds Checks: ✅

Significant changes in experiment optimization goals

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

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
❌	pycheck_lots_of_tags	% cpu utilization	+11.63	[+7.93, +15.32]	1	Logs
❌	basic_py_check	% cpu utilization	+5.28	[+1.15, +9.41]	1	Logs

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
❌	pycheck_lots_of_tags	% cpu utilization	+11.63	[+7.93, +15.32]	1	Logs
❌	basic_py_check	% cpu utilization	+5.28	[+1.15, +9.41]	1	Logs
➖	file_to_blackhole_1000ms_latency	egress throughput	+0.37	[-0.12, +0.86]	1	Logs
➖	tcp_syslog_to_blackhole	ingress throughput	+0.24	[+0.19, +0.29]	1	Logs
➖	otel_to_otel_logs	ingress throughput	+0.15	[-0.66, +0.96]	1	Logs
➖	file_to_blackhole_500ms_latency	egress throughput	+0.12	[-0.13, +0.37]	1	Logs
➖	idle_all_features	memory utilization	+0.05	[-0.10, +0.20]	1	Logs
➖	file_to_blackhole_0ms_latency	egress throughput	+0.01	[-0.32, +0.35]	1	Logs
➖	uds_dogstatsd_to_api	ingress throughput	+0.01	[-0.10, +0.11]	1	Logs
➖	tcp_dd_logs_filter_exclude	ingress throughput	+0.00	[-0.01, +0.01]	1	Logs
➖	file_to_blackhole_100ms_latency	egress throughput	-0.02	[-0.25, +0.20]	1	Logs
➖	file_to_blackhole_300ms_latency	egress throughput	-0.04	[-0.22, +0.14]	1	Logs
➖	uds_dogstatsd_to_api_cpu	% cpu utilization	-0.13	[-0.85, +0.60]	1	Logs
➖	idle	memory utilization	-0.24	[-0.30, -0.18]	1	Logs
➖	file_tree	memory utilization	-2.87	[-3.01, -2.74]	1	Logs

Bounds Checks Passed

perf	experiment	bounds_check_name	replicates_passed	links
✅	file_to_blackhole_0ms_latency	memory_usage	10/10
✅	file_to_blackhole_1000ms_latency	memory_usage	10/10
✅	file_to_blackhole_100ms_latency	memory_usage	10/10
✅	file_to_blackhole_300ms_latency	memory_usage	10/10
✅	file_to_blackhole_500ms_latency	memory_usage	10/10
✅	idle	memory_usage	10/10

Explanation

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

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".

[jszwedko]

Approving @DataDog/agent-processing-and-routing owned files.

[pducolin]

❓ question
This assume calls could come only from tests, is this linter limited to _test files? Should you suggest using a component in agent code?

[hush-hush]

The linter scan everything but using those method outside of test files would be a sign something really wrong.

I'll update the error to mention the config component outside of test 👍 .

[GustavoCaso]

Would it make sense to add the build tag //go:build test to the mock package? That way we warranty that is not used outside of tests?

datadog-agent/pkg/config/mock/mock.go

Line 7 in fa03594

package mock

[hush-hush]

That would prevent outside repo like OTEL/Serverless from using the mock without themselves using the test build tag. Add build tags is not always possible, especially in open-source repo like OTEL.

[GustavoCaso]

That is a lot of new imports 😮. Are those just because we imported the "github.com/DataDog/datadog-agent/pkg/config/mock" package?

[hush-hush]

Yes, sadly currently pkg/config/setup depends on way too many things and need to be better split.

[hush-hush]

/merge

[dd-devflow]

🚂 MergeQueue: pull request added to the queue

The median merge time in main is 27m.

Use /merge -c to cancel this operation!