feat: fiber.Context implement context.Context

[pjebs]

Description

Makes fiber.Context implement context.Context

Fixes #3344

Changes introduced

fiber.Context now incorporates :

1. Done() <-chan struct{}
2. Err() error
3. Value(key any) any
4. Deadline() (deadline time.Time, ok bool)

Type of change

Please delete options that are not relevant.

• [x] Enhancement (improvement to existing features and functionality)
• [x] Documentation update (changes to documentation)

Checklist

Before you submit your pull request, please make sure you meet these requirements:

• [x] Followed the inspiration of the Express.js framework for new functionalities, making them similar in usage.
• [x] Conducted a self-review of the code and provided comments for complex or critical parts.
• [x] Updated the documentation in the /docs/ directory for Fiber's documentation.
• [x] Added or updated unit tests to validate the effectiveness of the changes or new features.
• [x] Ensured that new and existing unit tests pass locally with the changes.
• [x] Verified that any new dependencies are essential and have been agreed upon by the maintainers/community.
• [x] Aimed for optimal performance with minimal allocations in the new code.
• [x] Provided benchmarks for the new code to analyze and improve upon.

[coderabbitai[bot]]

Walkthrough

The changes remove the previous mechanism for storing and retrieving a context.Context from the Fiber context, replacing it with direct implementation of the context.Context interface on fiber.Ctx. Four new methods (Deadline, Done, Err, Value) are added, with documentation and tests updated to reflect these changes and the limitations of the underlying fasthttp library.

Changes

File(s)	Change Summary
ctx.go, ctx_interface_gen.go	Remove Context()/SetContext(context.Context); add Deadline, Done, Err, Value methods to fiber.Ctx.
ctx_test.go	Remove tests for old context methods; add tests for new context interface methods and value retrieval.
middleware/timeout/timeout.go, middleware/timeout/timeout_test.go	Update timeout middleware and its tests to use the new context interface directly on fiber.Ctx.
docs/api/ctx.md	Update documentation to show fiber.Ctx implements context.Context, remove Context() docs, add examples.
docs/whats_new.md	Add note that fiber.Ctx now implements context.Context with new methods and usage examples.

Sequence Diagram(s)

sequenceDiagram
    participant User
    participant FiberCtx
    participant Handler

    User->>FiberCtx: Set Locals(key, value)
    Handler->>FiberCtx: Value(key)
    FiberCtx-->>Handler: value (from Locals)
    Handler->>FiberCtx: Deadline()
    FiberCtx-->>Handler: (zero, false)
    Handler->>FiberCtx: Done()
    FiberCtx-->>Handler: nil
    Handler->>FiberCtx: Err()
    FiberCtx-->>Handler: nil

Assessment against linked issues

Objective	Addressed	Explanation
Make fiber.Ctx implement context.Context interface, removing Context()/SetContext() ([#3344])	✅
Ensure new methods (Deadline, Done, Err, Value) are present and documented ([#3344])	✅
Remove reliance on standard context.Context storage in fiber.Ctx ([#3344])	✅
Update tests and documentation to match new context interface ([#3344])	✅

Possibly related PRs

• gofiber/fiber#3364: Also removes storing a separate context.Context in fiber.Ctx and adds direct implementation of the context interface.
• gofiber/fiber#3365: Reverts middleware changes that copied values into a standard context, simplifying context usage in middleware.
• gofiber/fiber#3200: Adds support for retrieving request ID from either fiber.Ctx or standard context.Context, related to context interface usage.

Suggested reviewers

• sixcolors
• gaby
• ReneWerner87
• efectn

Poem

In Fiber’s code, a change takes root,
Contexts now are resolute!
No more juggling, no more fuss,
The interface is part of us.
Deadline, Done, and Value too—
Simpler flows for me and you.
🐰✨

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📥 Commits

Reviewing files that changed from the base of the PR and between 6949586132ff60503b89ec34a4fa595689c3ea44 and 2ef037b54836c6e3b12dc428d8d3601962e83cbc.

📒 Files selected for processing (1)

• ctx.go (4 hunks)

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

• ctx.go

⏰ Context from checks skipped due to timeout of 90000ms (4)

• GitHub Check: unit (1.24.x, macos-13)
• GitHub Check: unit (1.23.x, macos-13)
• GitHub Check: repeated
• GitHub Check: Compare

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• [ ] 📝 Generate Docstrings

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[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 84.39%. Comparing base (a5f76a7) to head (2ef037b). Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3382      +/-   ##
==========================================
- Coverage   84.41%   84.39%   -0.02%     
==========================================
  Files         120      120              
  Lines       12194    12190       -4     
==========================================
- Hits        10293    10288       -5     
  Misses       1473     1473              
- Partials      428      429       +1     

Flag	Coverage Δ
unittests	84.39% <100.00%> (-0.02%)	:arrow_down:

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[gaby]

@pjebs Can you take a look at the merge conflicts and failing tests

[gaby]

Please update the pull request title and description template.

The documentation for context also needs to be updated

[gaby]

@coderabbitai full review

[coderabbitai[bot]]

✅ Actions performed

Full review triggered.

[gaby]

@pjebs Are the concerns about timeout middleware valid? I believe they are.

[pjebs]

The concerns about timeout are not valid.

timeoutContext, cancel := context.WithTimeout(ctx, timeout) // ctx is fiber.Ctx
defer cancel()

timeoutContext will be a (unexported) context.timerCtx: https://cs.opensource.google/go/go/+/refs/tags/go1.24.3:src/context/context.go;l=631 It will timeout only based on timeout value since ctx is a nop. This is by design.

Also relevant: https://github.com/gofiber/fiber/issues/3394

[pjebs]

tests are flaky