prefect: add container-based config discovery support

[vitkyrka]

What does this PR do?

Adds container-based config discovery support to prefect.

• Port selection rationale: Port 4200 is Prefect's official documented default port for the self-hosted Prefect Server API when run as a standalone container.

• Endpoint field: The check's config field is prefect_url (a full API base URL, e.g. http://host:4200/api), not openmetrics_endpoint, so spec.yaml uses the manual from_ports strategy form rather than the discovery/openmetrics_from_ports template.

• ad_identifier (prefect): The short name of the official prefecthq/prefect Docker Hub image, with no registry/org prefix and no tag.

• test_e2e_discovery_all_candidates compose service: Passed compose_service='prefect-server' explicitly, since the fixture's compose file defines multiple services and the helper's default-service fallback would not match any of them. Of the ones running the prefecthq/prefect image, only prefect-server exposes any ports.

Motivation

https://datadoghq.atlassian.net/browse/DSCVR-539

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• Add qa/required if this PR needs QA validation, or qa/skip-qa if it does not. Exactly one of the two is required.
• If you need to backport this PR to another branch, you can add the backport/<branch-name> label to the PR and it will automatically open a backport PR once this one is merged

[datadog-datadog-prod-us1-2]

 

🎉 All green!

🧪 All tests passed
❄️ No new flaky tests detected

🔄 Datadog auto-retried 2 jobs - 2 passed on retry

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 88.17%

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 969b47e | Docs | Datadog PR Page | Give us feedback!}

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 969b47e211

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[dd-octo-sts]

Validation Report

All 21 validations passed.

Show details

Validation	Description	Status
agent-reqs	Verify check versions match the Agent requirements file	✅
ci	Validate CI configuration and code coverage settings	✅
codeowners	Validate every integration has a CODEOWNERS entry	✅
config	Validate default configuration files against spec.yaml	✅
dep	Verify dependency pins are consistent and Agent-compatible	✅
http	Validate integrations use the HTTP wrapper correctly	✅
imports	Validate check imports do not use deprecated modules	✅
integration-style	Validate check code style conventions	✅
jmx-metrics	Validate JMX metrics definition files and config	✅
labeler	Validate PR labeler config matches integration directories	✅
legacy-signature	Validate no integration uses the legacy Agent check signature	✅
license-headers	Validate Python files have proper license headers	✅
licenses	Validate third-party license attribution list	✅
metadata	Validate metadata.csv metric definitions	✅
models	Validate configuration data models match spec.yaml	✅
openmetrics	Validate OpenMetrics integrations disable the metric limit	✅
package	Validate Python package metadata and naming	✅
qa-label	Validate the pull request declares whether it needs QA for the next Agent release	✅
readmes	Validate README files have required sections	✅
saved-views	Validate saved view JSON file structure and fields	✅
version	Validate version consistency between package and changelog	✅

View full run