Add http client & unburden zenrpc-middleware

Makefile

@@ -13,4 +13,7 @@ lint:
 	@golangci-lint run
 
 run:
-	@go run example/main.go
+	@go run example/main.go
+
+mod:
+	@go mod tidy

README.md

@@ -28,6 +28,21 @@ A comprehensive Go utility package providing common application framework compon
 - **Database Monitoring**: Connection tracking and replica status
 - **API Exposure**: Public/private API configuration tracking
 
+### HTTP Client
+- **Pre-configured Client**: HTTP client with automatic metrics and internal headers
+- **Transport Wrappers**: Composable transport layers for metrics and header injection
+- **Caller Tracking**: Context-based caller identification for metrics
+
+### Request Management
+- **X-Request-ID**: Automatic generation, validation, and propagation
+- **Context Integration**: Request ID stored in context for easy access
+- **Header Management**: CORS and custom header support
+
+### Context Utilities
+- **Metadata Context**: Store and retrieve request metadata (IP, User-Agent, Platform, Version, Country)
+- **Debug Support**: Debug ID and SQL group tracking for logging
+- **Integration Support**: Sentry Hub and method tracking
+
 ## Usage Examples
 
 Please see example/main.go
@@ -86,6 +101,22 @@ func callInternalService() {
 }
 ```
 
+### HTTP Client with Metrics
+
+```go
+// Create pre-configured HTTP client for internal service calls
+client := appkit.NewHTTPClient("externalsrv", appkit.Version(), 30*time.Second)
+
+// Set caller name in context for metrics tracking
+ctx := appkit.NewCallerNameContext(context.Background(), "externalsrv")
+
+req, _ := http.NewRequestWithContext(ctx, http.MethodGet, "http://api-service/endpoint", nil)
+resp, _ := client.Do(req)
+
+// Usage with clients generated by vmkteam/rpcgen
+arithsrvClient := arithsrv.NewClient(arithsrvUrl, appkit.NewHTTPClient("arithsrv", appkit.Version(), 5*time.Second))
+```
+
 ## API Reference
 
 ### Core Functions
@@ -105,19 +136,67 @@ func callInternalService() {
 - `HTTPMetrics(serverName string) echo.MiddlewareFunc` - Prometheus HTTP metrics middleware
 - `MetadataManager` - Service metadata configuration and metrics
 
+### HTTP Client
+
+- `NewHTTPClient(appName, version string, timeout time.Duration) *http.Client` - Creates HTTP client with metrics and internal headers
+- `WithMetricsTransport(base http.RoundTripper) http.RoundTripper` - Wraps transport with Prometheus metrics
+- `WithHeadersTransport(base http.RoundTripper, headers http.Header) http.RoundTripper` - Wraps transport to inject headers for each request
+- `NewCallerNameContext(ctx context.Context, callerName string) context.Context` - Creates context with caller name for metrics
+- `CallerNameFromContext(ctx context.Context) string` - Retrieves caller name from context
+
+### Request ID & HTTP Handlers
+
+- `XRequestIDFromContext(ctx context.Context) string` - Retrieves X-Request-ID from context
+- `NewXRequestIDContext(ctx context.Context, requestID string) context.Context` - Creates context with X-Request-ID
+- `SetXRequestIDFromCtx(ctx context.Context, req *http.Request)` - Adds X-Request-ID from context to request headers
+- `CORS(next http.Handler, headers ...string) http.Handler` - CORS middleware for HTTP handlers
+- `XRequestID(next http.Handler) http.Handler` - X-Request-ID middleware for HTTP handlers
+- `EchoHandler(next http.Handler) echo.HandlerFunc` - Wraps HTTP handler as Echo handler
+- `EchoSentryHubContext() echo.MiddlewareFunc` - Echo middleware to apply Sentry hub to context
+- `EchoIPContext() echo.MiddlewareFunc` - Echo middleware to apply client IP to context
+
+### Context Utilities
+
+- `NewDebugIDContext(ctx context.Context, debugID uint64) context.Context` - Creates context with debug ID
+- `DebugIDFromContext(ctx context.Context) uint64` - Retrieves debug ID from context
+- `NewSQLGroupContext(ctx context.Context, group string) context.Context` - Creates context with SQL group for debug logging
+- `SQLGroupFromContext(ctx context.Context) string` - Retrieves SQL group from context
+- `NewSentryHubContext(ctx context.Context, sentryHub *sentry.Hub) context.Context` - Creates context with Sentry Hub
+- `SentryHubFromContext(ctx context.Context) (*sentry.Hub, bool)` - Retrieves Sentry Hub from context
+- `NewIPContext(ctx context.Context, ip string) context.Context` - Creates context with IP address
+- `IPFromContext(ctx context.Context) string` - Retrieves IP address from context
+- `NewUserAgentContext(ctx context.Context, ua string) context.Context` - Creates context with User-Agent
+- `UserAgentFromContext(ctx context.Context) string` - Retrieves User-Agent from context
+- `NewNotificationContext(ctx context.Context) context.Context` - Creates context with JSONRPC2 notification flag
+- `NotificationFromContext(ctx context.Context) bool` - Retrieves JSONRPC2 notification flag from context
+- `NewIsDevelContext(ctx context.Context, isDevel bool) context.Context` - Creates context with isDevel flag
+- `IsDevelFromContext(ctx context.Context) bool` - Retrieves isDevel flag from context
+- `NewPlatformContext(ctx context.Context, platform string) context.Context` - Creates context with platform
+- `PlatformFromContext(ctx context.Context) string` - Retrieves platform from context
+- `NewVersionContext(ctx context.Context, version string) context.Context` - Creates context with version
+- `VersionFromContext(ctx context.Context) string` - Retrieves version from context
+- `NewCountryContext(ctx context.Context, country string) context.Context` - Creates context with country
+- `CountryFromContext(ctx context.Context) string` - Retrieves country from context
+- `NewMethodContext(ctx context.Context, method string) context.Context` - Creates context with method
+- `MethodFromContext(ctx context.Context) string` - Retrieves method from context
+
 ## Dependencies
 
 - [Echo](https://echo.labstack.com/) - High performance HTTP framework
 - [Prometheus](https://prometheus.io/) - Metrics collection and monitoring
 - [Sentry](https://sentry.io/) - Error tracking and monitoring
-- [zenrpc-middleware](https://github.com/vmkteam/zenrpc-middleware) - RPC middleware utilities
 
 ## Metrics Exported
 
-### HTTP Metrics
+### HTTP Server Metrics
 - `app_http_requests_total` - Total HTTP requests by method/path/status
 - `app_http_responses_duration_seconds` - Response time distribution
 
+### HTTP Client Metrics
+- `app_http_client_requests_total` - Total client requests by code/method/caller/origin
+- `app_http_client_responses_duration_seconds` - Client response time distribution
+- `app_http_client_requests_inflight` - Current inflight client requests by caller/origin
+
 ### Service Metadata Metrics
 - `app_metadata_service` - Service configuration information
 - `app_metadata_db_connections_total` - Database connection counts

appkit.go

@@ -6,6 +6,8 @@ import (
 	"runtime/debug"
 )
 
+type contextKey string
+
 // Version returns app version from VCS info.
 func Version() string {
 	result := "devel"

client.go

@@ -0,0 +1,132 @@
+package appkit
+
+import (
+	"context"
+	"net/http"
+	"strconv"
+	"sync"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+const (
+	ctxCallerName contextKey = "callerName"
+)
+
+var (
+	clientMetricsOnce sync.Once
+	clientRequests    = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "app",
+			Subsystem: "http_client",
+			Name:      "requests_total",
+			Help:      "Requests count by code/method/client/origin.",
+		},
+		[]string{"code", "method", "caller", "origin"},
+	)
+	clientDurations = prometheus.NewSummaryVec(
+		prometheus.SummaryOpts{
+			Namespace: "app",
+			Subsystem: "http_client",
+			Name:      "responses_duration_seconds",
+			Help:      "Response time by code/method/client/origin.",
+		},
+		[]string{"code", "method", "caller", "origin"},
+	)
+	clientInflights = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Namespace: "app",
+			Subsystem: "http_client",
+			Name:      "requests_inflight",
+			Help:      "Gauge for inflight requests.",
+		},
+		[]string{"caller", "origin"},
+	)
+)
+
+// NewCallerNameContext creates new context with caller name.
+func NewCallerNameContext(ctx context.Context, callerName string) context.Context {
+	return context.WithValue(ctx, ctxCallerName, callerName)
+}
+
+// CallerNameFromContext returns caller name from context.
+func CallerNameFromContext(ctx context.Context) string {
+	r, _ := ctx.Value(ctxCallerName).(string)
+	return r
+}
+
+type metricsRoundTripper struct {
+	base http.RoundTripper
+}
+
+func (m *metricsRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	var origin string
+	if req.URL != nil {
+		origin = req.URL.Scheme + "://" + req.URL.Host
+	}
+	labels := prometheus.Labels{
+		"caller": CallerNameFromContext(req.Context()),
+		"origin": origin,
+	}
+
+	start := time.Now()
+	clientInflights.With(labels).Inc()
+	resp, err := m.base.RoundTrip(req)
+	clientInflights.With(labels).Dec()
+	duration := time.Since(start).Seconds()
+
+	labels["method"] = req.Method
+	if resp != nil {
+		labels["code"] = strconv.Itoa(resp.StatusCode)
+	}
+
+	clientRequests.With(labels).Inc()
+	clientDurations.With(labels).Observe(duration)
+
+	return resp, err
+}
+
+// WithMetricsTransport wraps http transport, adds client metrics tracking.
+func WithMetricsTransport(base http.RoundTripper) http.RoundTripper {
+	clientMetricsOnce.Do(func() {
+		prometheus.MustRegister(clientRequests, clientDurations, clientInflights)
+	})
+	return &metricsRoundTripper{base: base}
+}
+
+type headerRoundTripper struct {
+	base    http.RoundTripper
+	headers http.Header
+}
+
+func (h *headerRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	reqClone := req.Clone(req.Context())
+
+	for key, values := range h.headers {
+		for _, value := range values {
+			reqClone.Header.Add(key, value)
+		}
+	}
+
+	return h.base.RoundTrip(reqClone)
+}
+
+// WithHeadersTransport wraps http transport, adds provided headers for each request.
+func WithHeadersTransport(base http.RoundTripper, headers http.Header) http.RoundTripper {
+	return &headerRoundTripper{
+		base:    base,
+		headers: headers,
+	}
+}
+
+// NewHTTPClient returns http client with metrics and headers for internal service calls.
+func NewHTTPClient(appName, version string, timeout time.Duration) *http.Client {
+	transport := WithHeadersTransport(http.DefaultTransport, NewInternalHeaders(appName, version))
+	transport = WithMetricsTransport(transport)
+
+	return &http.Client{
+		Timeout:   timeout,
+		Transport: transport,
+	}
+}

echo.go

@@ -12,7 +12,6 @@ import (
 	sentryecho "github.com/getsentry/sentry-go/echo"
 	"github.com/labstack/echo/v4"
 	"github.com/prometheus/client_golang/prometheus"
-	zm "github.com/vmkteam/zenrpc-middleware"
 )
 
 const DefaultServerName = "default"
@@ -32,7 +31,7 @@ func NewEcho() *echo.Echo {
 	}))
 
 	// use zenrpc middlewares
-	e.Use(zm.EchoIPContext(), zm.EchoSentryHubContext())
+	e.Use(EchoIPContext(), EchoSentryHubContext())
 
 	return e
 }

go.mod

@@ -3,20 +3,17 @@ module github.com/vmkteam/appkit
 go 1.24.5
 
 require (
+	github.com/getsentry/sentry-go v0.35.3
 	github.com/getsentry/sentry-go/echo v0.35.3
 	github.com/labstack/echo/v4 v4.13.4
 	github.com/prometheus/client_golang v1.23.2
-	github.com/vmkteam/zenrpc-middleware v1.2.2
+	github.com/vmkteam/zenrpc/v2 v2.2.12
 )
 
 require (
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
-	github.com/getsentry/sentry-go v0.35.3 // indirect
-	github.com/go-pg/pg/v10 v10.15.0 // indirect
-	github.com/go-pg/zerochecker v0.2.0 // indirect
 	github.com/gorilla/websocket v1.5.3 // indirect
-	github.com/jinzhu/inflection v1.0.0 // indirect
 	github.com/kr/text v0.2.0 // indirect
 	github.com/labstack/gommon v0.4.2 // indirect
 	github.com/mattn/go-colorable v0.1.14 // indirect
@@ -25,19 +22,12 @@ require (
 	github.com/prometheus/client_model v0.6.2 // indirect
 	github.com/prometheus/common v0.66.1 // indirect
 	github.com/prometheus/procfs v0.17.0 // indirect
-	github.com/tmthrgd/go-hex v0.0.0-20190904060850-447a3041c3bc // indirect
 	github.com/valyala/bytebufferpool v1.0.0 // indirect
 	github.com/valyala/fasttemplate v1.2.2 // indirect
-	github.com/vmihailenco/bufpool v0.1.11 // indirect
-	github.com/vmihailenco/msgpack/v5 v5.4.1 // indirect
-	github.com/vmihailenco/tagparser v0.1.2 // indirect
-	github.com/vmihailenco/tagparser/v2 v2.0.0 // indirect
-	github.com/vmkteam/zenrpc/v2 v2.2.12 // indirect
 	go.yaml.in/yaml/v2 v2.4.3 // indirect
 	golang.org/x/crypto v0.42.0 // indirect
 	golang.org/x/net v0.44.0 // indirect
 	golang.org/x/sys v0.36.0 // indirect
 	golang.org/x/text v0.29.0 // indirect
 	google.golang.org/protobuf v1.36.9 // indirect
-	mellium.im/sasl v0.3.2 // indirect
 )