Create shared server for loki.source.+ network targets (grafana#3581)

(cherry picked from commit 4a3c4a7)

component/common/net/config.go

@@ -0,0 +1,114 @@
+// Package http contains a River serializable definition of the weaveworks weaveworks config in
+// https://github.com/weaveworks/common/blob/master/server/server.go#L62.
+package net
+
+import (
+	"flag"
+	"time"
+
+	weaveworks "github.com/weaveworks/common/server"
+)
+
+const (
+	DefaultHTTPPort = 8080
+	DefaultGRPCPort = 8081
+)
+
+// ServerConfig is a River configuration that allows one to configure a weaveworks.Server. It
+// exposes a subset of the available configurations.
+type ServerConfig struct {
+	// HTTP configures the HTTP weaveworks. Note that despite the block being present or not,
+	// the weaveworks is always started.
+	HTTP *HTTPConfig `river:"http,block,optional"`
+
+	// GRPC configures the gRPC weaveworks. Note that despite the block being present or not,
+	// the weaveworks is always started.
+	GRPC *GRPCConfig `river:"grpc,block,optional"`
+
+	// GracefulShutdownTimeout configures a timeout to gracefully shut down the server.
+	GracefulShutdownTimeout time.Duration `river:"graceful_shutdown_timeout,attr,optional"`
+}
+
+// HTTPConfig configures the HTTP weaveworks started by weaveworks.Server.
+type HTTPConfig struct {
+	ListenAddress      string        `river:"listen_address,attr,optional"`
+	ListenPort         int           `river:"listen_port,attr,optional"`
+	ConnLimit          int           `river:"conn_limit,attr,optional"`
+	ServerReadTimeout  time.Duration `river:"server_read_timeout,attr,optional"`
+	ServerWriteTimeout time.Duration `river:"server_write_timeout,attr,optional"`
+	ServerIdleTimeout  time.Duration `river:"server_idle_timeout,attr,optional"`
+}
+
+// Into applies the configs from HTTPConfig into a weaveworks.Into.
+func (h *HTTPConfig) Into(c *weaveworks.Config) {
+	c.HTTPListenAddress = h.ListenAddress
+	c.HTTPListenPort = h.ListenPort
+	c.HTTPConnLimit = h.ConnLimit
+	c.HTTPServerReadTimeout = h.ServerReadTimeout
+	c.HTTPServerWriteTimeout = h.ServerWriteTimeout
+	c.HTTPServerIdleTimeout = h.ServerIdleTimeout
+}
+
+// GRPCConfig configures the gRPC weaveworks started by weaveworks.Server.
+type GRPCConfig struct {
+	ListenAddress              string        `river:"listen_address,attr,optional"`
+	ListenPort                 int           `river:"listen_port,attr,optional"`
+	ConnLimit                  int           `river:"conn_limit,attr,optional"`
+	MaxConnectionAge           time.Duration `river:"max_connection_age,attr,optional"`
+	MaxConnectionAgeGrace      time.Duration `river:"max_connection_age_grace,attr,optional"`
+	MaxConnectionIdle          time.Duration `river:"max_connection_idle,attr,optional"`
+	ServerMaxRecvMsg           int           `river:"server_max_recv_msg_size,attr,optional"`
+	ServerMaxSendMsg           int           `river:"server_max_send_msg_size,attr,optional"`
+	ServerMaxConcurrentStreams uint          `river:"server_max_concurrent_streams,attr,optional"`
+}
+
+// Into applies the configs from GRPCConfig into a weaveworks.Into.
+func (g *GRPCConfig) Into(c *weaveworks.Config) {
+	c.GRPCListenAddress = g.ListenAddress
+	c.GRPCListenPort = g.ListenPort
+	c.GRPCConnLimit = g.ConnLimit
+	c.GRPCServerMaxConnectionAge = g.MaxConnectionAge
+	c.GRPCServerMaxConnectionAgeGrace = g.MaxConnectionAgeGrace
+	c.GRPCServerMaxConnectionIdle = g.MaxConnectionIdle
+	c.GPRCServerMaxRecvMsgSize = g.ServerMaxRecvMsg
+	c.GRPCServerMaxSendMsgSize = g.ServerMaxSendMsg
+	c.GPRCServerMaxConcurrentStreams = g.ServerMaxConcurrentStreams
+}
+
+func (c *ServerConfig) UnmarshalRiver(f func(v interface{}) error) error {
+	type config ServerConfig
+	if err := f((*config)(c)); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Convert converts the River-based ServerConfig into a weaveworks.Config object.
+func (c *ServerConfig) Convert() weaveworks.Config {
+	cfg := newDefaultConfig()
+	if c.HTTP != nil {
+		c.HTTP.Into(&cfg)
+	}
+	if c.GRPC != nil {
+		c.GRPC.Into(&cfg)
+	}
+	// If set, override. Don't allow a zero-value since it configure a context.WithTimeout, so the user should at least
+	// give a >0 value to it
+	if c.GracefulShutdownTimeout != 0 {
+		cfg.ServerGracefulShutdownTimeout = c.GracefulShutdownTimeout
+	}
+	return cfg
+}
+
+// newDefaultConfig creates a new weaveworks.Config object with some overridden defaults.
+func newDefaultConfig() weaveworks.Config {
+	c := weaveworks.Config{}
+	c.RegisterFlags(flag.NewFlagSet("empty", flag.ContinueOnError))
+	c.HTTPListenPort = DefaultHTTPPort
+	c.GRPCListenPort = DefaultGRPCPort
+	// By default, do not register instrumentation since every metric is later registered
+	// inside a custom register
+	c.RegisterInstrumentation = false
+	return c
+}

component/common/net/config_test.go

@@ -0,0 +1,105 @@
+package net
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/grafana/agent/pkg/river"
+	weaveworks "github.com/weaveworks/common/server"
+)
+
+func TestConfig(t *testing.T) {
+	type testcase struct {
+		raw         string
+		errExpected bool
+		assert      func(t *testing.T, config weaveworks.Config)
+	}
+	var cases = map[string]testcase{
+		"empty config applies defaults": {
+			raw: ``,
+			assert: func(t *testing.T, config weaveworks.Config) {
+				// custom defaults
+				require.Equal(t, DefaultHTTPPort, config.HTTPListenPort)
+				require.Equal(t, DefaultGRPCPort, config.GRPCListenPort)
+				// defaults inherited from weaveworks
+				require.Equal(t, "", config.HTTPListenAddress)
+				require.Equal(t, "", config.GRPCListenAddress)
+				require.False(t, config.RegisterInstrumentation)
+				require.Equal(t, time.Second*30, config.ServerGracefulShutdownTimeout)
+			},
+		},
+		"overriding defaults": {
+			raw: `
+			graceful_shutdown_timeout = "1m"
+			http {
+				listen_port = 8080
+				listen_address = "0.0.0.0"
+				conn_limit = 10
+				server_write_timeout = "10s"
+			}`,
+			assert: func(t *testing.T, config weaveworks.Config) {
+				require.Equal(t, 8080, config.HTTPListenPort)
+				require.Equal(t, "0.0.0.0", config.HTTPListenAddress)
+				require.Equal(t, 10, config.HTTPConnLimit)
+				require.Equal(t, time.Second*10, config.HTTPServerWriteTimeout)
+
+				require.Equal(t, time.Minute, config.ServerGracefulShutdownTimeout)
+			},
+		},
+		"all params": {
+			raw: `
+			graceful_shutdown_timeout = "1m"
+			http {
+				listen_address = "0.0.0.0"
+				listen_port = 1
+				conn_limit = 2
+				server_read_timeout = "2m"
+				server_write_timeout = "3m"
+				server_idle_timeout = "4m"
+			}
+
+			grpc {
+				listen_address = "0.0.0.1"
+				listen_port = 3
+				conn_limit = 4
+				max_connection_age = "5m"
+				max_connection_age_grace = "6m"
+				max_connection_idle = "7m"
+				server_max_recv_msg_size = 5
+				server_max_send_msg_size = 6
+				server_max_concurrent_streams = 7
+			}`,
+			assert: func(t *testing.T, config weaveworks.Config) {
+				// general
+				require.Equal(t, time.Minute, config.ServerGracefulShutdownTimeout)
+				// http
+				require.Equal(t, "0.0.0.0", config.HTTPListenAddress)
+				require.Equal(t, 1, config.HTTPListenPort)
+				require.Equal(t, 2, config.HTTPConnLimit)
+				require.Equal(t, time.Minute*2, config.HTTPServerReadTimeout)
+				require.Equal(t, time.Minute*3, config.HTTPServerWriteTimeout)
+				require.Equal(t, time.Minute*4, config.HTTPServerIdleTimeout)
+				// grpc
+				require.Equal(t, "0.0.0.1", config.GRPCListenAddress)
+				require.Equal(t, 3, config.GRPCListenPort)
+				require.Equal(t, 5*time.Minute, config.GRPCServerMaxConnectionAge)
+				require.Equal(t, 6*time.Minute, config.GRPCServerMaxConnectionAgeGrace)
+				require.Equal(t, 7*time.Minute, config.GRPCServerMaxConnectionIdle)
+				require.Equal(t, 5, config.GPRCServerMaxRecvMsgSize)
+				require.Equal(t, 6, config.GRPCServerMaxSendMsgSize)
+				require.Equal(t, uint(7), config.GPRCServerMaxConcurrentStreams)
+			},
+		},
+	}
+	for name, tc := range cases {
+		t.Run(name, func(t *testing.T) {
+			cfg := ServerConfig{}
+			err := river.Unmarshal([]byte(tc.raw), &cfg)
+			require.Equal(t, tc.errExpected, err != nil)
+			wConfig := cfg.Convert()
+			tc.assert(t, wConfig)
+		})
+	}
+}

component/common/net/server.go

@@ -0,0 +1,92 @@
+package net
+
+import (
+	"fmt"
+
+	"github.com/go-kit/log"
+	"github.com/go-kit/log/level"
+	"github.com/gorilla/mux"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/common/model"
+	"github.com/weaveworks/common/logging"
+	weaveworks "github.com/weaveworks/common/server"
+)
+
+// TargetServer is wrapper around weaveworks.Server that handles some common configuration used in all flow components
+// that expose a network server. It just handles configuration and initialization, the handlers implementation are left
+// to the consumer.
+type TargetServer struct {
+	logger           log.Logger
+	config           *weaveworks.Config
+	metricsNamespace string
+	server           *weaveworks.Server
+}
+
+// NewTargetServer creates a new TargetServer, applying some defaults to the server configuration.
+func NewTargetServer(logger log.Logger, metricsNamespace string, reg prometheus.Registerer, config *ServerConfig) (*TargetServer, error) {
+	if !model.IsValidMetricName(model.LabelValue(metricsNamespace)) {
+		return nil, fmt.Errorf("metrics namespace is not prometheus compatiible: %s", metricsNamespace)
+	}
+
+	ts := &TargetServer{
+		logger:           logger,
+		metricsNamespace: metricsNamespace,
+	}
+
+	// convert from River into the weaveworks config
+	serverCfg := config.Convert()
+	// Set the config to the new combined config.
+	// Avoid logging entire received request on failures
+	serverCfg.ExcludeRequestInLog = true
+	// Configure dedicated metrics registerer
+	serverCfg.Registerer = reg
+	// Persist crafter config in server
+	ts.config = &serverCfg
+	// To prevent metric collisions because all metrics are going to be registered in the global Prometheus registry.
+	ts.config.MetricsNamespace = ts.metricsNamespace
+	// We don't want the /debug and /metrics endpoints running, since this is not the main Flow HTTP server.
+	// We want this target to expose the least surface area possible, hence disabling WeaveWorks HTTP server metrics
+	// and debugging functionality.
+	ts.config.RegisterInstrumentation = false
+	// Add logger to weaveworks
+	ts.config.Log = logging.GoKit(ts.logger)
+
+	return ts, nil
+}
+
+// MountAndRun mounts the handlers and starting the server.
+func (ts *TargetServer) MountAndRun(mountRoute func(router *mux.Router)) error {
+	level.Info(ts.logger).Log("msg", "starting server")
+	srv, err := weaveworks.New(*ts.config)
+	if err != nil {
+		return err
+	}
+
+	ts.server = srv
+	mountRoute(ts.server.HTTP)
+
+	go func() {
+		err := srv.Run()
+		if err != nil {
+			level.Error(ts.logger).Log("msg", "server shutdown with error", "err", err)
+		}
+	}()
+
+	return nil
+}
+
+// HTTPListenAddr returns the listen address of the HTTP server.
+func (ts *TargetServer) HTTPListenAddr() string {
+	return ts.server.HTTPListenAddr().String()
+}
+
+// GRPCListenAddr returns the listen address of the gRPC server.
+func (ts *TargetServer) GRPCListenAddr() string {
+	return ts.server.GRPCListenAddr().String()
+}
+
+// StopAndShutdown stops and shuts down the underlying server.
+func (ts *TargetServer) StopAndShutdown() {
+	ts.server.Stop()
+	ts.server.Shutdown()
+}

component/common/net/server_test.go

@@ -0,0 +1,45 @@
+package net
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+	"strings"
+	"testing"
+
+	"github.com/go-kit/log"
+	"github.com/gorilla/mux"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/stretchr/testify/require"
+)
+
+func TestTargetServer(t *testing.T) {
+	// dependencies
+	w := log.NewSyncWriter(os.Stderr)
+	logger := log.NewLogfmtLogger(w)
+	reg := prometheus.NewRegistry()
+
+	ts, err := NewTargetServer(logger, "test_namespace", reg, &ServerConfig{})
+	require.NoError(t, err)
+
+	ts.MountAndRun(func(router *mux.Router) {
+		router.Methods("GET").Path("/hello").Handler(http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+			w.WriteHeader(http.StatusOK)
+		}))
+	})
+	defer ts.StopAndShutdown()
+
+	// test mounted endpoint
+	req, err := http.NewRequest("GET", fmt.Sprintf("http://%s/hello", ts.HTTPListenAddr()), nil)
+	require.NoError(t, err)
+	res, err := http.DefaultClient.Do(req)
+	require.NoError(t, err)
+	require.Equal(t, 200, res.StatusCode)
+
+	// assert all metrics have the prefix applied
+	metrics, err := reg.Gather()
+	require.NoError(t, err)
+	for _, m := range metrics {
+		require.True(t, strings.HasPrefix(m.GetName(), "test_namespace"))
+	}
+}

component/loki/source/gcplog/gcplog.go

@@ -7,13 +7,14 @@ import (
 	"sync"
 
 	"github.com/go-kit/log/level"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/prometheus/model/relabel"
+
 	"github.com/grafana/agent/component"
 	"github.com/grafana/agent/component/common/loki"
 	flow_relabel "github.com/grafana/agent/component/common/relabel"
 	gt "github.com/grafana/agent/component/loki/source/gcplog/internal/gcplogtarget"
 	"github.com/grafana/agent/pkg/util"
-	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/prometheus/model/relabel"
 )
 
 func init() {