Add timeout knobs (#25)

* Add timeout knobs
* Add missing godoc and unexport unnecessarily exported constants

README.md

@@ -48,5 +48,9 @@ Usage of ./observatorium:
   -web.listen string
     	The address on which internal server runs. (default ":8080")
   -web.timeout duration
-    	The maximum duration before timing out the request, and closing idle connections. (default 5m0s)
+    	The maximum duration before timing out the request, and closing idle connections. (default 2m0s)
+  -web.timeout.read duration
+    	The maximum duration before reading the entire request, including the body. (default 2m0s)
+  -web.timeout.write duration
+    	The maximum duration  before timing out writes of the response. (default 2m0s)
 ```

internal/proxy/option.go

@@ -3,9 +3,15 @@ package proxy
 import "time"
 
 type options struct {
-	bufferCount     int
-	bufferSizeBytes int
-	flushInterval   time.Duration
+	bufferCount           int
+	bufferSizeBytes       int
+	maxIdleConns          int
+	flushInterval         time.Duration
+	timeout               time.Duration
+	keepAlive             time.Duration
+	idleConnTimeout       time.Duration
+	tlsHandshakeTimeout   time.Duration
+	expectContinueTimeout time.Duration
 }
 
 // Option overrides behavior of Proxy.
@@ -19,23 +25,65 @@ func (f optionFunc) apply(o *options) {
 	f(o)
 }
 
-// WithBufferCount TODO
+// WithBufferCount sets the buffer count option for the reverse proxy.
 func WithBufferCount(i int) Option {
 	return optionFunc(func(o *options) {
 		o.bufferCount = i
 	})
 }
 
-// WithBufferSizeBytes TODO
+// WithBufferSizeBytes sets the buffer size bytes option for the reverse proxy.
 func WithBufferSizeBytes(i int) Option {
 	return optionFunc(func(o *options) {
 		o.bufferSizeBytes = i
 	})
 }
 
-// WithFlushInterval TODO
+// WithFlushInterval sets the flush interval option for the reverse proxy.
 func WithFlushInterval(t time.Duration) Option {
 	return optionFunc(func(o *options) {
 		o.flushInterval = t
 	})
 }
+
+// WithMaxIdsConns sets the max idle conns for the underlying reverse proxy transport.
+func WithMaxIdsConns(i int) Option {
+	return optionFunc(func(o *options) {
+		o.maxIdleConns = i
+	})
+}
+
+// WithIdleConnTimeout sets the idle timeout duration for the underlying reverse proxy transport.
+func WithIdleConnTimeout(t time.Duration) Option {
+	return optionFunc(func(o *options) {
+		o.idleConnTimeout = t
+	})
+}
+
+// WithTimeout sets the timeout duration for the underlying reverse proxy connection.
+func WithTimeout(t time.Duration) Option {
+	return optionFunc(func(o *options) {
+		o.timeout = t
+	})
+}
+
+// WithKeepAlive sets the keep alive duration for the underlying reverse proxy connection.
+func WithKeepAlive(t time.Duration) Option {
+	return optionFunc(func(o *options) {
+		o.keepAlive = t
+	})
+}
+
+// WithTLSHandshakeTimeout sets the max TLS handshake timeout duration for the underlying reverse proxy transport.
+func WithTLSHandshakeTimeout(t time.Duration) Option {
+	return optionFunc(func(o *options) {
+		o.tlsHandshakeTimeout = t
+	})
+}
+
+// WithExpectContinueTimeout sets the max expected continue timeout duration for the underlying reverse proxy transport.
+func WithExpectContinueTimeout(t time.Duration) Option {
+	return optionFunc(func(o *options) {
+		o.expectContinueTimeout = t
+	})
+}

internal/proxy/proxy.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"io/ioutil"
 	stdlog "log"
+	"net"
 	"net/http"
 	"net/http/httputil"
 	"net/url"
@@ -17,12 +18,26 @@ import (
 )
 
 const (
-	// DefaultBufferCount TODO
+	// DefaultBufferCount is the default value for the maximum size of the buffer pool for the reverse proxy.
 	DefaultBufferCount = 2 * 1024
-	// DefaultBufferSizeBytes TODO
+	// DefaultBufferSizeBytes is the default value for the length of the buffers in the buffer pool for the reverse proxy.
 	DefaultBufferSizeBytes = 32 * 1024
-	// DefaultFlushInterval TODO
+	// DefaultFlushInterval is the default value for the flush interval of reverse proxy to flush to the client while copying the response body.
 	DefaultFlushInterval = time.Duration(-1)
+
+	// defaultTimeout is the default value for the maximum amount of time a dial will wait for a connect to complete.
+	defaultTimeout = 30 * time.Second
+	// defaultKeepAlive is the default value for the interval between keep-alive probes for an active network connection.
+	defaultKeepAlive = 30 * time.Second
+	// defaultMaxIdleConns is the default value for the maximum idle (keep-alive) connections to keep per-host.
+	defaultMaxIdleConns = 100
+	// defaultIdleConnTimeout is the default value for the maximum amount of time an idle (keep-alive) connection will remain idle before closing itself.
+	defaultIdleConnTimeout = 90 * time.Second
+	// defaultTLSHandshakeTimeout is the default value for the maximum amount of time waiting to wait for a TLS handshake.
+	defaultTLSHandshakeTimeout = 10 * time.Second
+	// defaultExpectContinueTimeout is the default value for the amount of time to wait for a server's first response headers after fully writing the request headers,
+	// if the request has an "Expect: 100-continue" header.
+	defaultExpectContinueTimeout = 1 * time.Second
 )
 
 type Proxy struct {
@@ -32,9 +47,15 @@ type Proxy struct {
 
 func New(logger log.Logger, prefix string, endpoint *url.URL, opts ...Option) *Proxy {
 	options := options{
-		bufferCount:     DefaultBufferCount,
-		bufferSizeBytes: DefaultBufferSizeBytes,
-		flushInterval:   DefaultFlushInterval,
+		bufferCount:           DefaultBufferCount,
+		bufferSizeBytes:       DefaultBufferSizeBytes,
+		flushInterval:         DefaultFlushInterval,
+		maxIdleConns:          defaultMaxIdleConns,
+		timeout:               defaultTimeout,
+		keepAlive:             defaultKeepAlive,
+		idleConnTimeout:       defaultIdleConnTimeout,
+		tlsHandshakeTimeout:   defaultTLSHandshakeTimeout,
+		expectContinueTimeout: defaultExpectContinueTimeout,
 	}
 
 	for _, o := range opts {
@@ -64,6 +85,18 @@ func New(logger log.Logger, prefix string, endpoint *url.URL, opts ...Option) *P
 		Director:      director,
 		ErrorLog:      stdErrLogger,
 		FlushInterval: options.flushInterval,
+		Transport: &http.Transport{
+			Proxy: http.ProxyFromEnvironment,
+			Dial: (&net.Dialer{
+				Timeout:   options.timeout,
+				KeepAlive: options.keepAlive,
+				DualStack: true,
+			}).Dial,
+			MaxIdleConns:          options.maxIdleConns,
+			IdleConnTimeout:       options.idleConnTimeout,
+			TLSHandshakeTimeout:   options.tlsHandshakeTimeout,
+			ExpectContinueTimeout: options.expectContinueTimeout,
+		},
 	}
 
 	return &Proxy{logger: logger, reverseProxy: &rev}

internal/server/option.go

@@ -9,9 +9,13 @@ import (
 )
 
 type options struct {
-	gracePeriod time.Duration
-	timeout     time.Duration
-	tlsConfig   *tls.Config
+	gracePeriod    time.Duration
+	timeout        time.Duration
+	requestTimeout time.Duration
+	readTimeout    time.Duration
+	writeTimeout   time.Duration
+
+	tlsConfig *tls.Config
 
 	metricsUIEndpoint    *url.URL
 	metricsReadEndpoint  *url.URL
@@ -34,24 +38,38 @@ func (f optionFunc) apply(o *options) {
 	f(o)
 }
 
-// WithGracePeriod TODO
+// WithGracePeriod sets graceful shutdown period for the server.
 func WithGracePeriod(t time.Duration) Option {
 	return optionFunc(func(o *options) {
 		o.gracePeriod = t
 	})
 }
 
-// WithListen TODO
+// WithListen sets the port to listen for the server.
 func WithListen(s string) Option {
 	return optionFunc(func(o *options) {
 		o.listen = s
 	})
 }
 
-// WithTimeout TODO
-func WithTimeout(t time.Duration) Option {
+// WithRequestTimeout sets the timeout duration for an individual request.
+func WithRequestTimeout(t time.Duration) Option {
+	return optionFunc(func(o *options) {
+		o.requestTimeout = t
+	})
+}
+
+// WithReadTimeout sets the read timeout duration  for the underlying HTTP server.
+func WithReadTimeout(t time.Duration) Option {
+	return optionFunc(func(o *options) {
+		o.readTimeout = t
+	})
+}
+
+// WithWriteTimeout sets the write timeout duration  for the underlying HTTP server.
+func WithWriteTimeout(t time.Duration) Option {
 	return optionFunc(func(o *options) {
-		o.timeout = t
+		o.writeTimeout = t
 	})
 }
 
@@ -69,28 +87,28 @@ func WithMetricUIEndpoint(u *url.URL) Option {
 	})
 }
 
-// WithMetricReadEndpoint TODO
+// WithMetricReadEndpoint sets the URL to proxy metrics read request to.
 func WithMetricReadEndpoint(u *url.URL) Option {
 	return optionFunc(func(o *options) {
 		o.metricsReadEndpoint = u
 	})
 }
 
-// WithMetricWriteEndpoint TODO
+// WithMetricWriteEndpoint sets the URL to proxy metrics write request to.
 func WithMetricWriteEndpoint(u *url.URL) Option {
 	return optionFunc(func(o *options) {
 		o.metricsWriteEndpoint = u
 	})
 }
 
-// WithProfile TODO
+// WithProfile sets the option to enable/disable profiler endpoint.
 func WithProfile(p bool) Option {
 	return optionFunc(func(o *options) {
 		o.profile = p
 	})
 }
 
-// WithProxyOptions TODO
+// WithProxyOptions sets the proxy options fot the underlying reverse proxy.
 func WithProxyOptions(opts ...proxy.Option) Option {
 	return optionFunc(func(o *options) {
 		o.proxyOptions = opts

internal/server/server.go

@@ -17,10 +17,19 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
+// DefaultGracePeriod is the default value of the duration gracefully shuts down the server without interrupting any active connections.
 const DefaultGracePeriod = 5 * time.Second
-const DefaultTimeout = 5 * time.Minute
 
-// Server TODO
+// DefaultRequestTimeout is the default value of the timeout duration per request.
+const DefaultRequestTimeout = 2 * time.Minute
+
+// DefaultReadTimeout is the default value of the maximum duration for reading the entire request, including the body.
+const DefaultReadTimeout = 2 * time.Minute
+
+// DefaultWriteTimeout is the default value of the maximum duration before timing out writes of the response.
+const DefaultWriteTimeout = 2 * time.Minute
+
+// Server defines parameters for running an HTTP server.
 type Server struct {
 	logger log.Logger
 	prober *prober.Prober
@@ -29,7 +38,7 @@ type Server struct {
 	opts options
 }
 
-// New creates a new Server
+// New creates a new Server.
 func New(logger log.Logger, reg *prometheus.Registry, opts ...Option) Server {
 	options := options{
 		gracePeriod: DefaultGracePeriod,
@@ -45,7 +54,7 @@ func New(logger log.Logger, reg *prometheus.Registry, opts ...Option) Server {
 	r.Use(middleware.RealIP)
 	r.Use(middleware.Recoverer)
 	r.Use(middleware.StripSlashes)
-	r.Use(middleware.Timeout(options.timeout))
+	r.Use(middleware.Timeout(options.requestTimeout))
 
 	if options.profile {
 		r.Mount("/debug", middleware.Profiler())
@@ -109,15 +118,17 @@ func New(logger log.Logger, reg *prometheus.Registry, opts ...Option) Server {
 		logger: logger,
 		prober: p,
 		srv: &http.Server{
-			Addr:      options.listen,
-			Handler:   r,
-			TLSConfig: options.tlsConfig,
+			Addr:         options.listen,
+			Handler:      r,
+			TLSConfig:    options.tlsConfig,
+			ReadTimeout:  options.readTimeout,
+			WriteTimeout: options.writeTimeout,
 		},
 		opts: options,
 	}
 }
 
-// ListenAndServe TODO
+// ListenAndServe listens on the TCP network address and handles connections with given server configuration.
 func (s *Server) ListenAndServe() error {
 	level.Info(s.logger).Log("msg", "starting the HTTP server", "address", s.opts.listen)
 	s.prober.Ready()
@@ -130,7 +141,7 @@ func (s *Server) ListenAndServe() error {
 	return s.srv.ListenAndServe()
 }
 
-// Shutdown TODO
+// Shutdown gracefully shuts down the server.
 func (s *Server) Shutdown(err error) {
 	s.prober.NotReady(err)