96 lines
2.6 KiB
Markdown
96 lines
2.6 KiB
Markdown
# httpx
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HTTP client for Go microservices. Retry, load balancing, circuit breaking, all as `http.RoundTripper` middleware. stdlib only, zero external deps.
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```
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go get git.codelab.vc/pkg/httpx
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```
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## Quick start
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```go
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client := httpx.New(
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httpx.WithBaseURL("https://api.example.com"),
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httpx.WithTimeout(10*time.Second),
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httpx.WithRetry(retry.WithMaxAttempts(3)),
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httpx.WithMiddleware(
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middleware.UserAgent("my-service/1.0"),
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middleware.BearerAuth(func(ctx context.Context) (string, error) {
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return os.Getenv("API_TOKEN"), nil
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}),
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),
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)
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defer client.Close()
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resp, err := client.Get(ctx, "/users/123")
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if err != nil {
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log.Fatal(err)
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}
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var user User
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resp.JSON(&user)
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```
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## Packages
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Everything is a `func(http.RoundTripper) http.RoundTripper`. Use them with `httpx.Client` or plug into a plain `http.Client`.
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| Package | What it does |
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|---------|-------------|
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| `retry` | Exponential/constant backoff, Retry-After support. Idempotent methods only by default. |
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| `balancer` | Round robin, failover, weighted random. Optional background health checks. |
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| `circuitbreaker` | Per-host state machine (closed/open/half-open). Stops hammering dead endpoints. |
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| `middleware` | Logging (slog), default headers, bearer/basic auth, panic recovery. |
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The client assembles them in this order:
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```
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Request → Logging → Your Middleware → Retry → Circuit Breaker → Balancer → Transport
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```
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Retry wraps the circuit breaker and balancer, so each attempt can pick a different endpoint.
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## Multi-DC setup
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```go
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client := httpx.New(
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httpx.WithEndpoints(
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balancer.Endpoint{URL: "https://dc1.api.internal", Weight: 3},
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balancer.Endpoint{URL: "https://dc2.api.internal", Weight: 1},
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),
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httpx.WithBalancer(balancer.WithStrategy(balancer.WeightedRandom())),
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httpx.WithRetry(retry.WithMaxAttempts(4)),
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httpx.WithCircuitBreaker(circuitbreaker.WithFailureThreshold(5)),
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httpx.WithLogger(slog.Default()),
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)
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defer client.Close()
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```
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## Standalone usage
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Each component works with any `http.Client`, no need for the full wrapper:
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```go
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// Just retry, nothing else
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transport := retry.Transport(retry.WithMaxAttempts(3))
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httpClient := &http.Client{
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Transport: transport(http.DefaultTransport),
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}
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```
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```go
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// Chain a few middlewares together
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chain := middleware.Chain(
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middleware.Logging(slog.Default()),
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middleware.UserAgent("my-service/1.0"),
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retry.Transport(retry.WithMaxAttempts(2)),
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)
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httpClient := &http.Client{
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Transport: chain(http.DefaultTransport),
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}
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```
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## Requirements
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Go 1.24+, stdlib only.
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