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gitea/suggestions.md
logikonline 66f3d55782 docs: add architectural review and suggestions
Comprehensive review covering:
- Chunked upload implementation critique with fixes
- API design improvements (batch ops, pagination, error format)
- Error handling & observability (tracing, structured logging)
- Reliability patterns (retry, circuit breaker, health checks)
- AI & automation friendliness (idempotency, error codes)
- Security considerations (audit logging, token scopes)
- Performance optimizations (caching, compression)
- Phased implementation roadmap
2026-01-08 09:09:08 -05:00

26 KiB

Gitea Architecture Review & Suggestions

Reviewer: Senior Architect Date: January 2026 Scope: Full codebase review with focus on API, services, and recent chunked upload implementation


Executive Summary

Gitea demonstrates a well-designed, pragmatic architecture suitable for a mature self-hosted Git platform. The codebase follows clean layered patterns (routers → services → models) with good separation of concerns. However, there are opportunities to improve operational observability, reliability, developer experience, and AI/automation friendliness.

This document presents findings organized by priority and effort level.


Table of Contents

  1. Chunked Upload Implementation Review
  2. API Design Improvements
  3. Error Handling & Observability
  4. Reliability & Resilience
  5. Developer Experience
  6. AI & Automation Friendliness
  7. Security Considerations
  8. Performance Optimizations
  9. Implementation Roadmap

1. Chunked Upload Implementation Review

What Was Done Well

  • Clean separation: model (upload_session.go), service (chunked.go), handler (upload.go)
  • Resumable uploads with session status tracking
  • Automatic cleanup via cron job
  • Follows existing Gitea patterns for API handlers and models

Issues to Address

1.1 Missing Chunk Verification (HIGH)

Problem: No checksum verification for uploaded chunks. Corrupted chunks will produce corrupted files.

Suggestion:

// Add to UploadSession model
type UploadSession struct {
    // ... existing fields
    ChecksumAlgorithm string `xorm:"DEFAULT 'sha256'"` // sha256, md5, none
    ExpectedChecksum  string `xorm:""`                  // Full file checksum
}

// Add to chunk upload
type ChunkMetadata struct {
    ChunkNumber int64  `json:"chunk_number"`
    Checksum    string `json:"checksum"` // Chunk checksum
    Size        int64  `json:"size"`
}

1.2 No Concurrent Upload Protection (MEDIUM)

Problem: Same chunk can be uploaded multiple times concurrently, causing race conditions.

Suggestion:

// Add file locking or atomic operations
func SaveChunk(ctx context.Context, session *UploadSession, chunkNum int64, ...) error {
    lockPath := session.GetChunkPath(chunkNum) + ".lock"
    lock, err := acquireFileLock(lockPath)
    if err != nil {
        return fmt.Errorf("chunk %d is being uploaded by another request", chunkNum)
    }
    defer lock.Release()
    // ... save chunk
}

1.3 Missing Progress Webhook (MEDIUM)

Problem: No way to notify external systems of upload progress.

Suggestion:

// Emit webhook on upload milestones
if session.ChunksReceived % 10 == 0 || session.IsComplete() {
    notify_service.UploadProgress(ctx, session)
}

1.4 No Rate Limiting (MEDIUM)

Problem: Unlimited chunk uploads could exhaust server resources.

Suggestion:

// Add rate limiting middleware for upload endpoints
m.Group("/uploads", func() {
    // ... routes
}, rateLimit(100, time.Minute)) // 100 chunks per minute per user

1.5 Temp File Cleanup on Failure (LOW)

Problem: If AssembleChunks fails partway through, temp files may not be cleaned up.

Suggestion:

func AssembleChunks(...) (*Attachment, error) {
    defer func() {
        if r := recover(); r != nil {
            cleanupTempFiles(session)
            panic(r)
        }
    }()
    // ... existing logic
}

2. API Design Improvements

2.1 Standardized Error Response Format (HIGH)

Current State: Error responses vary in format across endpoints.

Suggestion: Adopt RFC 7807 Problem Details format:

// modules/structs/error.go
type APIError struct {
    Type     string            `json:"type"`               // URI reference
    Title    string            `json:"title"`              // Short summary
    Status   int               `json:"status"`             // HTTP status code
    Detail   string            `json:"detail"`             // Explanation
    Instance string            `json:"instance,omitempty"` // Request URI
    Code     string            `json:"code"`               // Machine-readable code
    Errors   []ValidationError `json:"errors,omitempty"`   // Field-level errors
}

// Example response:
{
    "type": "https://gitea.io/errors/validation",
    "title": "Validation Failed",
    "status": 422,
    "detail": "The provided repository name is invalid",
    "code": "ERR_VALIDATION_FAILED",
    "errors": [
        {"field": "name", "message": "must be alphanumeric", "code": "ERR_INVALID_CHARS"}
    ]
}

2.2 Batch Operations API (HIGH)

Current State: No batch endpoints for bulk operations.

Suggestion: Add batch endpoints for common operations:

POST /api/v1/repos/{owner}/{repo}/issues/batch
POST /api/v1/repos/{owner}/{repo}/labels/batch
POST /api/v1/admin/users/batch
// Example batch request
{
    "operations": [
        {"action": "close", "issue_ids": [1, 2, 3]},
        {"action": "add_label", "issue_ids": [1, 2], "label_id": 5}
    ]
}

// Example batch response
{
    "results": [
        {"index": 0, "success": true, "affected": 3},
        {"index": 1, "success": false, "error": {"code": "ERR_NOT_FOUND", "detail": "Label 5 not found"}}
    ],
    "summary": {"total": 2, "succeeded": 1, "failed": 1}
}

2.3 Cursor-Based Pagination (MEDIUM)

Current State: Offset-based pagination can be slow for large datasets.

Suggestion: Add cursor-based pagination option:

GET /api/v1/repos/{owner}/{repo}/issues?cursor=eyJpZCI6MTAwfQ&limit=50
type PaginatedResponse struct {
    Data       []any  `json:"data"`
    NextCursor string `json:"next_cursor,omitempty"`
    PrevCursor string `json:"prev_cursor,omitempty"`
    HasMore    bool   `json:"has_more"`
    Total      int64  `json:"total,omitempty"` // Optional, expensive to compute
}

2.4 Field Selection (GraphQL-lite) (MEDIUM)

Current State: All fields returned on every request.

Suggestion: Add field selection parameter:

GET /api/v1/repos/{owner}/{repo}?fields=id,name,description,stars_count
// Reduces payload and database load
func filterFields(obj any, fields []string) map[string]any {
    // Return only requested fields
}

2.5 API Versioning Header (LOW)

Current State: No API version negotiation.

Suggestion: Add version header support:

Accept: application/vnd.gitea.v2+json
X-Gitea-API-Version: 2

3. Error Handling & Observability

3.1 Centralized Error Catalog (HIGH)

Current State: 100+ custom error types scattered across packages.

Suggestion: Create centralized error registry:

// modules/errors/catalog.go
package errors

type ErrorCode string

const (
    // Authentication errors (1xxx)
    ErrAuthRequired       ErrorCode = "ERR_1001"
    ErrInvalidToken       ErrorCode = "ERR_1002"
    ErrTokenExpired       ErrorCode = "ERR_1003"

    // Authorization errors (2xxx)
    ErrForbidden          ErrorCode = "ERR_2001"
    ErrNotRepoMember      ErrorCode = "ERR_2002"

    // Resource errors (3xxx)
    ErrUserNotFound       ErrorCode = "ERR_3001"
    ErrRepoNotFound       ErrorCode = "ERR_3002"
    ErrIssueNotFound      ErrorCode = "ERR_3003"

    // Validation errors (4xxx)
    ErrInvalidInput       ErrorCode = "ERR_4001"
    ErrNameTooLong        ErrorCode = "ERR_4002"

    // Upload errors (5xxx)
    ErrUploadSessionExpired ErrorCode = "ERR_5001"
    ErrChunkMissing         ErrorCode = "ERR_5002"
    ErrFileTooLarge         ErrorCode = "ERR_5003"
)

var errorMessages = map[ErrorCode]string{
    ErrAuthRequired: "Authentication required",
    ErrInvalidToken: "Invalid or malformed token",
    // ...
}

func (e ErrorCode) Error() string { return errorMessages[e] }
func (e ErrorCode) HTTPStatus() int { /* return appropriate status */ }

3.2 Request Tracing (HIGH)

Current State: No correlation IDs for request tracing.

Suggestion: Add OpenTelemetry integration:

// modules/web/middleware/tracing.go
func TracingMiddleware() func(http.Handler) http.Handler {
    return func(next http.Handler) http.Handler {
        return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
            traceID := r.Header.Get("X-Request-ID")
            if traceID == "" {
                traceID = uuid.New().String()
            }

            ctx := context.WithValue(r.Context(), TraceIDKey, traceID)
            w.Header().Set("X-Request-ID", traceID)

            // Add to structured logging
            log := log.WithField("trace_id", traceID)
            ctx = context.WithValue(ctx, LoggerKey, log)

            next.ServeHTTP(w, r.WithContext(ctx))
        })
    }
}

3.3 Structured Logging (MEDIUM)

Current State: Mix of structured and unstructured logging.

Suggestion: Standardize on JSON structured logs:

// All log entries should include:
{
    "timestamp": "2024-01-08T12:00:00Z",
    "level": "info",
    "trace_id": "abc-123",
    "user_id": 42,
    "repo_id": 100,
    "action": "create_issue",
    "duration_ms": 45,
    "message": "Issue created successfully"
}

3.4 Metrics Endpoint Enhancement (MEDIUM)

Current State: Basic Prometheus metrics.

Suggestion: Add business metrics:

// Metrics to add:
gitea_api_requests_total{method, endpoint, status}
gitea_api_request_duration_seconds{method, endpoint}
gitea_upload_sessions_active
gitea_upload_bytes_total
gitea_webhook_deliveries_total{status, hook_type}
gitea_webhook_delivery_duration_seconds
gitea_repository_operations_total{operation}

4. Reliability & Resilience

4.1 Webhook Retry with Exponential Backoff (HIGH)

Current State: Limited retry logic visible.

Suggestion:

// services/webhook/deliver.go
type RetryConfig struct {
    MaxRetries     int           // Default: 5
    InitialBackoff time.Duration // Default: 1s
    MaxBackoff     time.Duration // Default: 5m
    BackoffFactor  float64       // Default: 2.0
}

func DeliverWithRetry(ctx context.Context, task *HookTask, cfg RetryConfig) error {
    var lastErr error
    backoff := cfg.InitialBackoff

    for attempt := 0; attempt <= cfg.MaxRetries; attempt++ {
        err := Deliver(ctx, task)
        if err == nil {
            return nil
        }
        lastErr = err

        // Log retry
        log.Warn("Webhook delivery failed, retrying",
            "task_id", task.ID,
            "attempt", attempt+1,
            "next_backoff", backoff)

        select {
        case <-ctx.Done():
            return ctx.Err()
        case <-time.After(backoff):
        }

        backoff = time.Duration(float64(backoff) * cfg.BackoffFactor)
        if backoff > cfg.MaxBackoff {
            backoff = cfg.MaxBackoff
        }
    }

    // Move to dead letter queue
    if err := moveToDeadLetterQueue(ctx, task, lastErr); err != nil {
        log.Error("Failed to move to DLQ", "task_id", task.ID, "error", err)
    }

    return fmt.Errorf("webhook delivery failed after %d attempts: %w", cfg.MaxRetries, lastErr)
}

4.2 Circuit Breaker for External Services (MEDIUM)

Current State: No circuit breaker pattern.

Suggestion:

// modules/circuitbreaker/breaker.go
type CircuitBreaker struct {
    name          string
    maxFailures   int
    resetTimeout  time.Duration
    state         State // Closed, Open, HalfOpen
    failures      int
    lastFailure   time.Time
}

func (cb *CircuitBreaker) Execute(fn func() error) error {
    if cb.state == Open {
        if time.Since(cb.lastFailure) > cb.resetTimeout {
            cb.state = HalfOpen
        } else {
            return ErrCircuitOpen
        }
    }

    err := fn()
    if err != nil {
        cb.recordFailure()
        return err
    }

    cb.recordSuccess()
    return nil
}

// Usage for webhook delivery, OAuth providers, etc.
var webhookBreaker = NewCircuitBreaker("webhook", 5, time.Minute)

4.3 Graceful Degradation (MEDIUM)

Current State: Services fail hard on dependency failures.

Suggestion: Add fallback behaviors:

// Example: Search indexer fallback
func SearchIssues(ctx context.Context, query string) ([]Issue, error) {
    if indexer.IsHealthy() {
        return indexer.Search(ctx, query)
    }

    // Fallback to database search (slower but works)
    log.Warn("Search indexer unavailable, falling back to DB search")
    return db.SearchIssuesByTitle(ctx, query)
}

4.4 Health Check Endpoints (LOW)

Current State: Basic health check.

Suggestion: Add detailed health checks:

GET /api/v1/health
GET /api/v1/health/live    # Kubernetes liveness
GET /api/v1/health/ready   # Kubernetes readiness
{
    "status": "healthy",
    "version": "1.24.0",
    "checks": {
        "database": {"status": "up", "latency_ms": 2},
        "redis": {"status": "up", "latency_ms": 1},
        "search_indexer": {"status": "degraded", "message": "High latency"},
        "storage": {"status": "up", "free_space_gb": 450}
    }
}

5. Developer Experience

5.1 OpenAPI Spec Improvements (HIGH)

Current State: Swagger docs generated from code comments.

Suggestion: Enhance with examples and better descriptions:

// swagger:operation POST /repos/{owner}/{repo}/issues repository createIssue
// ---
// summary: Create an issue
// description: |
//   Creates a new issue in the repository. The authenticated user must have
//   write access to the repository.
//
//   ## Example
//   ```json
//   {"title": "Bug report", "body": "Description here", "labels": [1, 2]}
//   ```
// consumes:
// - application/json
// produces:
// - application/json
// parameters:
// - name: body
//   in: body
//   schema:
//     "$ref": "#/definitions/CreateIssueOption"
//   example:
//     title: "Bug: Login fails"
//     body: "When I try to login..."
//     labels: [1, 2]
// responses:
//   "201":
//     description: Issue created
//     schema:
//       "$ref": "#/definitions/Issue"
//     examples:
//       application/json:
//         id: 1
//         title: "Bug: Login fails"
//         state: "open"

5.2 SDK Generation (MEDIUM)

Current State: No official SDK libraries.

Suggestion: Generate SDKs from OpenAPI spec:

# Generate SDKs
openapi-generator generate -i api/v1/swagger.json -g python -o sdk/python
openapi-generator generate -i api/v1/swagger.json -g typescript-axios -o sdk/typescript
openapi-generator generate -i api/v1/swagger.json -g go -o sdk/go

5.3 CLI Tool Enhancement (MEDIUM)

Current State: Basic CLI for Git operations.

Suggestion: Add API CLI tool:

# Proposed gitea-cli commands
gitea-cli auth login --server https://gitea.example.com
gitea-cli repo list
gitea-cli repo create myrepo --private
gitea-cli issue create --title "Bug" --body "Description"
gitea-cli release create v1.0.0 --attach ./binary.zip
gitea-cli upload --chunked ./large-file.zip  # Uses chunked upload

5.4 Webhook Debugging Tools (LOW)

Current State: Limited visibility into webhook delivery.

Suggestion: Add webhook inspection endpoints:

GET /api/v1/repos/{owner}/{repo}/hooks/{id}/deliveries
GET /api/v1/repos/{owner}/{repo}/hooks/{id}/deliveries/{delivery_id}
POST /api/v1/repos/{owner}/{repo}/hooks/{id}/deliveries/{delivery_id}/redeliver

6. AI & Automation Friendliness

6.1 Machine-Readable Error Codes (HIGH)

Current State: Error messages are human-readable strings.

Suggestion: Always include machine-readable codes:

{
    "code": "ERR_REPO_ARCHIVED",
    "message": "Repository is archived and cannot be modified",
    "documentation_url": "https://docs.gitea.io/errors/ERR_REPO_ARCHIVED"
}

6.2 Idempotency Keys (HIGH)

Current State: No idempotency support for POST requests.

Suggestion: Add idempotency key header:

// Header: Idempotency-Key: <client-generated-uuid>

func IdempotencyMiddleware() func(http.Handler) http.Handler {
    return func(next http.Handler) http.Handler {
        return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
            if r.Method != "POST" && r.Method != "PUT" {
                next.ServeHTTP(w, r)
                return
            }

            key := r.Header.Get("Idempotency-Key")
            if key == "" {
                next.ServeHTTP(w, r)
                return
            }

            // Check cache
            if cached, found := idempotencyCache.Get(key); found {
                w.Header().Set("X-Idempotency-Replayed", "true")
                writeResponse(w, cached)
                return
            }

            // Capture response
            rec := httptest.NewRecorder()
            next.ServeHTTP(rec, r)

            // Cache successful responses
            if rec.Code >= 200 && rec.Code < 300 {
                idempotencyCache.Set(key, rec, 24*time.Hour)
            }

            copyResponse(w, rec)
        })
    }
}

6.3 Webhook Event Catalog (MEDIUM)

Current State: Events documented but not discoverable via API.

Suggestion: Add event discovery endpoint:

GET /api/v1/events
{
    "events": [
        {
            "name": "push",
            "description": "Triggered when commits are pushed",
            "payload_schema": {"$ref": "#/definitions/PushPayload"},
            "example": {...}
        },
        {
            "name": "issues",
            "description": "Triggered for issue events",
            "actions": ["opened", "closed", "edited", "labeled"],
            "payload_schema": {"$ref": "#/definitions/IssuePayload"}
        }
    ]
}

6.4 Async Operation Pattern (MEDIUM)

Current State: Long operations block HTTP requests.

Suggestion: Add async operation pattern for long-running tasks:

POST /api/v1/repos/{owner}/{repo}/mirror-sync
Response: 202 Accepted
{
    "operation_id": "op_abc123",
    "status": "pending",
    "status_url": "/api/v1/operations/op_abc123",
    "estimated_completion": "2024-01-08T12:05:00Z"
}

GET /api/v1/operations/op_abc123
{
    "operation_id": "op_abc123",
    "status": "running",
    "progress": 45,
    "started_at": "2024-01-08T12:00:00Z"
}

6.5 Rate Limit Headers (MEDIUM)

Current State: Limited rate limit visibility.

Suggestion: Add standard rate limit headers:

X-RateLimit-Limit: 5000
X-RateLimit-Remaining: 4990
X-RateLimit-Reset: 1704720000
X-RateLimit-Resource: api

6.6 Conditional Requests (LOW)

Current State: Limited ETag/If-Match support.

Suggestion: Add conditional request support:

GET /api/v1/repos/owner/repo
Response Headers:
  ETag: "abc123"
  Last-Modified: Wed, 08 Jan 2024 12:00:00 GMT

GET /api/v1/repos/owner/repo
Request Headers:
  If-None-Match: "abc123"
Response: 304 Not Modified

PUT /api/v1/repos/owner/repo
Request Headers:
  If-Match: "abc123"  # Prevents lost updates

7. Security Considerations

7.1 Audit Logging (HIGH)

Current State: Limited audit trail.

Suggestion: Add comprehensive audit logging:

type AuditEvent struct {
    ID          int64     `json:"id"`
    Timestamp   time.Time `json:"timestamp"`
    ActorID     int64     `json:"actor_id"`
    ActorIP     string    `json:"actor_ip"`
    Action      string    `json:"action"`      // "repo.create", "user.delete"
    Resource    string    `json:"resource"`    // "repository", "user"
    ResourceID  int64     `json:"resource_id"`
    OldValue    string    `json:"old_value,omitempty"`  // JSON
    NewValue    string    `json:"new_value,omitempty"`  // JSON
    UserAgent   string    `json:"user_agent"`
    TraceID     string    `json:"trace_id"`
}

// Store in separate audit_log table
// Expose via admin API: GET /api/v1/admin/audit-log

7.2 Token Scopes Enhancement (MEDIUM)

Current State: Basic token scopes.

Suggestion: Add granular scopes:

repo:read           # Read repository data
repo:write          # Push to repository
repo:delete         # Delete repository
issues:read         # Read issues
issues:write        # Create/edit issues
releases:read       # Read releases
releases:write      # Create releases
releases:upload     # Upload release assets (for CI)
admin:users         # Manage users
admin:repos         # Manage all repos
webhook:manage      # Manage webhooks

7.3 Request Signing (LOW)

Current State: Token-based auth only.

Suggestion: Add HMAC request signing for webhooks:

// For high-security integrations
signature := hmac.New(sha256.New, []byte(secret))
signature.Write([]byte(timestamp + "." + requestBody))
expectedSig := hex.EncodeToString(signature.Sum(nil))

// Header: X-Gitea-Signature: sha256=<signature>
// Header: X-Gitea-Timestamp: <unix-timestamp>

8. Performance Optimizations

8.1 Response Compression (HIGH)

Current State: Gzip available but not always used.

Suggestion: Ensure compression for all JSON responses:

// Middleware to compress responses > 1KB
func CompressionMiddleware(next http.Handler) http.Handler {
    return gziphandler.GzipHandler(next)
}

8.2 Database Query Optimization (MEDIUM)

Current State: Some N+1 query patterns.

Suggestion: Add eager loading for common associations:

// Instead of loading issues then loading users one by one
issues, _ := GetIssues(ctx, opts)
for _, issue := range issues {
    issue.Poster, _ = GetUser(issue.PosterID)  // N+1!
}

// Use eager loading
issues, _ := GetIssuesWithUsers(ctx, opts)  // Single JOIN query

8.3 Caching Layer (MEDIUM)

Current State: Limited caching.

Suggestion: Add Redis/memory caching for hot paths:

// Cache frequently accessed data
func GetRepository(ctx context.Context, id int64) (*Repository, error) {
    cacheKey := fmt.Sprintf("repo:%d", id)

    if cached, found := cache.Get(cacheKey); found {
        return cached.(*Repository), nil
    }

    repo, err := db.GetRepository(ctx, id)
    if err != nil {
        return nil, err
    }

    cache.Set(cacheKey, repo, 5*time.Minute)
    return repo, nil
}

8.4 Connection Pooling Tuning (LOW)

Current State: Default connection pool settings.

Suggestion: Add configurable pool settings:

[database]
MAX_OPEN_CONNS = 100
MAX_IDLE_CONNS = 10
CONN_MAX_LIFETIME = 1h
CONN_MAX_IDLE_TIME = 10m

9. Implementation Roadmap

Phase 1: Quick Wins (1-2 weeks)

Item Priority Effort Impact
Add request tracing (X-Request-ID) HIGH Low High
Add rate limit headers MEDIUM Low Medium
Add chunk checksum verification HIGH Low High
Standardize error response format HIGH Medium High

Phase 2: Foundation (2-4 weeks)

Item Priority Effort Impact
Centralized error catalog HIGH Medium High
Webhook retry with backoff HIGH Medium High
Idempotency key support HIGH Medium High
Audit logging HIGH Medium High
Health check endpoints LOW Low Medium

Phase 3: Enhancement (4-8 weeks)

Item Priority Effort Impact
Batch operations API HIGH High High
Cursor-based pagination MEDIUM Medium Medium
SDK generation pipeline MEDIUM Medium Medium
Circuit breaker pattern MEDIUM Medium Medium
Event discovery endpoint MEDIUM Low Medium

Phase 4: Advanced (8+ weeks)

Item Priority Effort Impact
Async operation pattern MEDIUM High Medium
Field selection (GraphQL-lite) MEDIUM High Medium
API versioning LOW High Low
Full OpenTelemetry integration MEDIUM High High

Appendix A: Chunked Upload Quick Fixes

// 1. Add checksum to chunk upload (upload.go)
func UploadChunk(ctx *context.APIContext) {
    // Get expected checksum from header
    expectedChecksum := ctx.Req.Header.Get("X-Chunk-Checksum")

    // ... save chunk ...

    // Verify checksum if provided
    if expectedChecksum != "" {
        actualChecksum := sha256sum(chunkData)
        if actualChecksum != expectedChecksum {
            ctx.APIError(http.StatusBadRequest, api.APIError{
                Code:   "ERR_CHECKSUM_MISMATCH",
                Detail: "Chunk checksum verification failed",
            })
            return
        }
    }
}

// 2. Add final file checksum verification (chunked.go)
func AssembleChunks(...) (*Attachment, error) {
    // ... assemble chunks ...

    // Verify final checksum if expected
    if session.ExpectedChecksum != "" {
        actualChecksum := computeFileChecksum(finalPath)
        if actualChecksum != session.ExpectedChecksum {
            return nil, fmt.Errorf("file checksum mismatch: expected %s, got %s",
                session.ExpectedChecksum, actualChecksum)
        }
    }

    // ... create attachment ...
}

Appendix B: Sample Error Catalog

// modules/errors/codes.go

package errors

// Error codes organized by category
const (
    // 1xxx - Authentication
    ErrCodeAuthRequired     = "ERR_1001"
    ErrCodeInvalidToken     = "ERR_1002"
    ErrCodeTokenExpired     = "ERR_1003"
    ErrCodeInvalidPassword  = "ERR_1004"
    ErrCode2FARequired      = "ERR_1005"

    // 2xxx - Authorization
    ErrCodeForbidden        = "ERR_2001"
    ErrCodeNotRepoMember    = "ERR_2002"
    ErrCodeNotOrgMember     = "ERR_2003"
    ErrCodeInsufficientPerm = "ERR_2004"

    // 3xxx - Resource Not Found
    ErrCodeUserNotFound     = "ERR_3001"
    ErrCodeRepoNotFound     = "ERR_3002"
    ErrCodeIssueNotFound    = "ERR_3003"
    ErrCodeReleaseNotFound  = "ERR_3004"
    ErrCodeBranchNotFound   = "ERR_3005"

    // 4xxx - Validation
    ErrCodeInvalidInput     = "ERR_4001"
    ErrCodeNameTooLong      = "ERR_4002"
    ErrCodeInvalidEmail     = "ERR_4003"
    ErrCodeDuplicateName    = "ERR_4004"

    // 5xxx - Upload
    ErrCodeSessionExpired   = "ERR_5001"
    ErrCodeChunkMissing     = "ERR_5002"
    ErrCodeFileTooLarge     = "ERR_5003"
    ErrCodeChecksumMismatch = "ERR_5004"
    ErrCodeInvalidFileType  = "ERR_5005"

    // 6xxx - Rate Limiting
    ErrCodeRateLimited      = "ERR_6001"
    ErrCodeTooManyRequests  = "ERR_6002"

    // 7xxx - Server
    ErrCodeInternal         = "ERR_7001"
    ErrCodeServiceDown      = "ERR_7002"
    ErrCodeTimeout          = "ERR_7003"
)

Document prepared for discussion. All suggestions should be evaluated against project priorities and resource constraints.