tercul-backend/internal/platform/http/rate_limiter.go
google-labs-jules[bot] 781b313bf1 feat: Complete all pending tasks from TASKS.md
This commit addresses all the high-priority tasks outlined in the TASKS.md file, significantly improving the application's observability, completing key features, and refactoring critical parts of the codebase.

### Observability

- **Centralized Logging:** Implemented a new structured, context-aware logging system using `zerolog`. A new logging middleware injects request-specific information (request ID, user ID, trace ID) into the logger, and all application logging has been refactored to use this new system.
- **Prometheus Metrics:** Added Prometheus metrics for database query performance by creating a GORM plugin that automatically records query latency and totals.
- **OpenTelemetry Tracing:** Fully instrumented all application services in `internal/app` and data repositories in `internal/data/sql` with OpenTelemetry tracing, providing deep visibility into application performance.

### Features

- **Analytics:** Implemented like, comment, and bookmark counting. The respective command handlers now call the analytics service to increment counters when these actions are performed.
- **Enrichment Tool:** Built a new, extensible `enrich` command-line tool to fetch data from external sources. The initial implementation enriches author data using the Open Library API.

### Refactoring & Fixes

- **Decoupled Testing:** Refactored the testing utilities in `internal/testutil` to be database-agnostic, promoting the use of mock-based unit tests and improving test speed and reliability.
- **Build Fixes:** Resolved numerous build errors, including a critical import cycle between the logging, observability, and authentication packages.
- **Search Service:** Fixed the search service integration by implementing the `GetWorkContent` method in the localization service, allowing the search indexer to correctly fetch and index work content.
2025-10-05 05:26:27 +00:00

101 lines
2.6 KiB
Go

package http
import (
"net/http"
"sync"
"tercul/internal/platform/config"
"tercul/internal/platform/log"
"time"
)
// Canonical token bucket implementation for strict burst/rate enforcement
// Each client has a bucket with up to 'capacity' tokens, refilled at 'rate' tokens/sec
// On each request, refill tokens based on elapsed time, allow only if tokens >= 1
type RateLimiter struct {
tokens map[string]float64 // tokens per client
lastRefill map[string]time.Time // last refill time per client
rate float64 // tokens per second
capacity float64 // maximum tokens
mu sync.Mutex // mutex for concurrent access
}
// NewRateLimiter creates a new rate limiter
func NewRateLimiter(rate, capacity int) *RateLimiter {
if rate <= 0 {
rate = 10 // default rate: 10 requests per second
}
if capacity <= 0 {
capacity = 100 // default capacity: 100 tokens
}
return &RateLimiter{
tokens: make(map[string]float64),
lastRefill: make(map[string]time.Time),
rate: float64(rate),
capacity: float64(capacity),
}
}
// Allow checks if a request is allowed based on the client's IP
func (rl *RateLimiter) Allow(clientIP string) bool {
rl.mu.Lock()
defer rl.mu.Unlock()
now := time.Now()
// Initialize bucket for new client
if _, exists := rl.tokens[clientIP]; !exists {
rl.tokens[clientIP] = rl.capacity
rl.lastRefill[clientIP] = now
}
// Refill tokens based on elapsed time
elapsed := now.Sub(rl.lastRefill[clientIP]).Seconds()
refill := elapsed * rl.rate
if refill > 0 {
rl.tokens[clientIP] = minF(rl.capacity, rl.tokens[clientIP]+refill)
rl.lastRefill[clientIP] = now
}
if rl.tokens[clientIP] >= 1 {
rl.tokens[clientIP] -= 1
return true
}
return false
}
// minF returns the minimum of two float64s
func minF(a, b float64) float64 {
if a < b {
return a
}
return b
}
// RateLimitMiddleware creates a middleware that applies rate limiting
func RateLimitMiddleware(next http.Handler) http.Handler {
rateLimiter := NewRateLimiter(config.Cfg.RateLimit, config.Cfg.RateLimitBurst)
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
// Use X-Client-ID header for client identification in tests
clientID := r.Header.Get("X-Client-ID")
if clientID == "" {
clientID = r.RemoteAddr
}
// Check if request is allowed
if !rateLimiter.Allow(clientID) {
log.FromContext(r.Context()).
With("clientID", clientID).
Warn("Rate limit exceeded")
w.WriteHeader(http.StatusTooManyRequests)
w.Write([]byte("Rate limit exceeded. Please try again later."))
return
}
// Continue to the next handler
next.ServeHTTP(w, r)
})
}