docs: Add raw_message_key examples and update UDP/TCP output plugin docs

[tristanphipson]

Changes

This PR updates and enhances the UDP and TCP output plugin documentation:

UDP Output Plugin:

• Clarified that the $ sign is required before the key name
• Added tabbed examples showing both top-level and nested field usage
• Included real-world syslog message examples demonstrating practical usage
• Added note clarifying that raw_message_key takes precedence over the format property
• Corrected existing documentation to ensure consistency with record accessor syntax

TCP Output Plugin:

• Added example configuration file showing basic TCP output setup
• Added example demonstrating how to use raw_message_key with the TCP output plugin

Why

Users frequently need to send raw message payloads (e.g., syslog lines) instead of JSON-formatted output. The existing documentation lacked the $ syntax requirement, concrete examples for both UDP and TCP, and configuration file samples showing how to reference fields at different nesting levels, leading to configuration confusion and incorrect usage.

Related

Related to general UDP and TCP output plugin documentation clarity and accuracy.

Summary by CodeRabbit

• Documentation
  • Expanded TCP/TLS output documentation with a new “Getting started” section, including configuration file examples for forwarding logs and guidance for sending raw log payloads.
  • Added/updated TCP/TLS examples for raw_message_key, including end-to-end YAML/CONF guidance and record accessor usage for top-level and nested fields.
  • Updated UDP output documentation to clarify raw_message_key behavior (raw payload sent; format ignored) and aligned examples with $ record accessor syntax.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 6e76c590-01c1-4148-8518-026cbeae9b5b

📥 Commits

Reviewing files that changed from the base of the PR and between 68f41af and c27ee02.

📒 Files selected for processing (1)

• pipeline/outputs/tcp-and-tls.md

✅ Files skipped from review due to trivial changes (1)

• pipeline/outputs/tcp-and-tls.md

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📝 Walkthrough

Walkthrough

Documentation updates add TCP/TLS getting started and raw message examples, and revise UDP raw_message_key wording and examples to use $-prefixed record accessors.

Changes

Output documentation updates

Layer / File(s)	Summary
TCP/TLS documentation additions pipeline/outputs/tcp-and-tls.md	Adds a Getting Started heading, a Configuration file section with fluent-bit.yaml and fluent-bit.conf examples, and a Raw message key section with YAML/CONF examples for top-level and nested fields.
UDP raw_message_key update pipeline/outputs/udp.md	Clarifies that raw_message_key sends the referenced field as raw payload and ignores format, and updates YAML/CONF examples to use $-prefixed record accessors.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Possibly related PRs

• fluent/fluent-bit-docs#2195: Updates the same UDP raw_message_key documentation and example flow.
• fluent/fluent-bit-docs#2292: Also adjusts pipeline/outputs/udp.md raw_message_key behavior and accessor syntax.
• fluent/fluent-bit-docs#2474: Touches raw_message_key configuration examples in the UDP output docs.

Suggested reviewers: esmerel, patrick-stephens

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the documentation updates for raw_message_key and the UDP/TCP output plugin docs.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[eschabell]

@tristanphipson added small lifting fixes, but thanks for the doc PR, merging!