output: azure_blob: compression with zstd update

[nberlee]

Document the new zstd option for Azure Blob network compression and explain how compress_blob inherits its codec, clarifying precedence between transport and blob-level compression.

⚠️ Heads-up: the code enabling Zstandard support is still under review in fluent/fluent-bit#11202, so please keep this docs PR in waiting-on-code-merge until that lands.

Summary by CodeRabbit

• Documentation
  • Updated Azure Blob output documentation with expanded compression options, now supporting gzip and zstd codecs.
  • Clarified compression behavior including default GZIP application and codec inheritance based on settings.
  • Added compatibility notes regarding compression and blob type configurations.

_{✏️ Tip: You can customize this high-level summary in your review settings.}

[coderabbitai]

Walkthrough

Documentation updates to the Azure Blob output: compress now documents both gzip and zstd; compress_blob expanded to describe final blockblob compression behavior, inheritance from compress, defaulting to GZIP when unset, and incompatibility with blob_type = appendblob.

Changes

Cohort / File(s)	Change Summary
Azure Blob Output Documentation pipeline/outputs/azure_blob.md	Expanded compress docs to list gzip and zstd; expanded compress_blob description to explain final blockblob compression behavior, inheritance from compress, default GZIP when compress is unset, and note incompatibility with blob_type = appendblob.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

• Focus review on pipeline/outputs/azure_blob.md to verify wording accuracy and consistency with existing docs/specs.

Poem

🐰 I nibble on docs beneath the moonlight,
Zstd and gzip twinkle, cozy and bright,
Blobs learn to tuck in their compressed beds,
Clear notes guide bytes to soft, sleepy threads,
Hooray — documentation hops into sight! 🥕✨

Pre-merge checks and finishing touches

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically identifies the main change: adding zstd compression support to the Azure Blob output documentation.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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📜 Recent review details

Configuration used: defaults

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 749e1f9 and 5d1f7e5.

📒 Files selected for processing (1)

• pipeline/outputs/azure_blob.md (1 hunks)

🚧 Files skipped from review as they are similar to previous changes (1)

• pipeline/outputs/azure_blob.md

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[coderabbitai]

Actionable comments posted: 1

📜 Review details

Configuration used: defaults

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 7fb7ce2 and 749e1f9.

📒 Files selected for processing (1)

• pipeline/outputs/azure_blob.md (1 hunks)

🔇 Additional comments (1)

pipeline/outputs/azure_blob.md (1)

29-30: Well-documented compression options and inheritance behavior.

The documentation clearly explains:

• Both compress (transport-level) and compress_blob (blob-level) compression support, with zstd now available
• How compress_blob inherits the codec from compress when set, establishing clear precedence
• The incompatibility constraint with blob_type = appendblob

These clarifications significantly improve the documentation. Once the underlying code merges in fluent-bit/fluent-bit#11202, verify that the documented behavior matches the implementation.

[patrick-stephens]

What does isn't compatible mean here? Does it error out or silently disable or something else?

[nberlee]

This wasn't changed, fluent-bit will error out as the two are not compatible, so fluent-bot will not be able to know what to do.
see https://github.com/fluent/fluent-bit/blob/master/plugins/out_azure_blob/azure_blob_conf.c#L669