feat(grpc): grpc keepalive configuration

config/flipt.schema.cue

@@ -247,6 +247,9 @@ import "strings"
 		grpc_port?:  int | *9000
 		cert_file?:  string
 		cert_key?:   string
+		grpc_conn_max_idle_time?: =~#duration
+		grpc_conn_max_age?: =~#duration
+		grpc_conn_max_age_grace?: =~#duration
 	}
 
 	#tracing: {

config/flipt.schema.json

@@ -856,6 +856,18 @@
         },
         "cert_key": {
           "type": "string"
+        },
+        "grpc_conn_max_idle_time": {
+          "type": "string",
+          "pattern": "^([0-9]+(ns|us|µs|ms|s|m|h))+$"
+        },
+        "grpc_conn_max_age": {
+          "type": "string",
+          "pattern": "^([0-9]+(ns|us|µs|ms|s|m|h))+$"
+        },
+        "grpc_conn_max_age_grace": {
+          "type": "string",
+          "pattern": "^([0-9]+(ns|us|µs|ms|s|m|h))+$"
         }
       },
       "required": [],

internal/cmd/grpc.go

@@ -53,6 +53,7 @@ import (
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/health"
+	"google.golang.org/grpc/keepalive"
 	"google.golang.org/grpc/reflection"
 	"google.golang.org/grpc/status"
 
@@ -358,7 +359,14 @@ func NewGRPCServer(
 	otel.SetTracerProvider(tracingProvider)
 	otel.SetTextMapPropagator(propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{}))
 
-	grpcOpts := []grpc.ServerOption{grpc.ChainUnaryInterceptor(interceptors...)}
+	grpcOpts := []grpc.ServerOption{
+		grpc.ChainUnaryInterceptor(interceptors...),
+		grpc.KeepaliveParams(keepalive.ServerParameters{
+			MaxConnectionIdle:     cfg.Server.GRPCConnectionMaxIdleTime,
+			MaxConnectionAge:      cfg.Server.GRPCConnectionMaxAge,
+			MaxConnectionAgeGrace: cfg.Server.GRPCConnectionMaxAgeGrace,
+		}),
+	}
 
 	if cfg.Server.Protocol == config.HTTPS {
 		creds, err := credentials.NewServerTLSFromFile(cfg.Server.CertFile, cfg.Server.CertKey)

internal/cmd/grpc_test.go

@@ -3,11 +3,15 @@ package cmd
 import (
 	"context"
 	"errors"
+	"fmt"
+	"path/filepath"
 	"sync"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 	"go.flipt.io/flipt/internal/config"
+	"go.flipt.io/flipt/internal/info"
+	"go.uber.org/zap/zaptest"
 )
 
 func TestGetTraceExporter(t *testing.T) {
@@ -110,3 +114,12 @@ func TestGetTraceExporter(t *testing.T) {
 		})
 	}
 }
+
+func TestNewGRPCServer(t *testing.T) {
+	tmp := t.TempDir()
+	cfg := &config.Config{}
+	cfg.Database.URL = fmt.Sprintf("file:%s", filepath.Join(tmp, "flipt.db"))
+	s, err := NewGRPCServer(context.Background(), zaptest.NewLogger(t), cfg, info.Flipt{}, false)
+	assert.NoError(t, err)
+	assert.NotEmpty(t, s.Server.GetServiceInfo())
+}

internal/config/config_test.go

@@ -873,6 +873,17 @@ func TestLoad(t *testing.T) {
 				return cfg
 			},
 		},
+		{
+			name: "grpc keepalive config provided",
+			path: "./testdata/server/grpc_keepalive.yml",
+			expected: func() *Config {
+				cfg := Default()
+				cfg.Server.GRPCConnectionMaxIdleTime = 1 * time.Hour
+				cfg.Server.GRPCConnectionMaxAge = 30 * time.Second
+				cfg.Server.GRPCConnectionMaxAgeGrace = 10 * time.Second
+				return cfg
+			},
+		},
 	}
 
 	for _, tt := range tests {

internal/config/server.go

@@ -3,6 +3,7 @@ package config
 import (
 	"encoding/json"
 	"os"
+	"time"
 
 	"github.com/spf13/viper"
 )
@@ -13,13 +14,16 @@ var _ defaulter = (*ServerConfig)(nil)
 // ServerConfig contains fields, which configure both HTTP and gRPC
 // API serving.
 type ServerConfig struct {
-	Host      string `json:"host,omitempty" mapstructure:"host" yaml:"host,omitempty"`
-	Protocol  Scheme `json:"protocol,omitempty" mapstructure:"protocol" yaml:"protocol,omitempty"`
-	HTTPPort  int    `json:"httpPort,omitempty" mapstructure:"http_port" yaml:"http_port,omitempty"`
-	HTTPSPort int    `json:"httpsPort,omitempty" mapstructure:"https_port" yaml:"https_port,omitempty"`
-	GRPCPort  int    `json:"grpcPort,omitempty" mapstructure:"grpc_port" yaml:"grpc_port,omitempty"`
-	CertFile  string `json:"-" mapstructure:"cert_file" yaml:"-"`
-	CertKey   string `json:"-" mapstructure:"cert_key" yaml:"-"`
+	Host                      string        `json:"host,omitempty" mapstructure:"host" yaml:"host,omitempty"`
+	Protocol                  Scheme        `json:"protocol,omitempty" mapstructure:"protocol" yaml:"protocol,omitempty"`
+	HTTPPort                  int           `json:"httpPort,omitempty" mapstructure:"http_port" yaml:"http_port,omitempty"`
+	HTTPSPort                 int           `json:"httpsPort,omitempty" mapstructure:"https_port" yaml:"https_port,omitempty"`
+	GRPCPort                  int           `json:"grpcPort,omitempty" mapstructure:"grpc_port" yaml:"grpc_port,omitempty"`
+	CertFile                  string        `json:"-" mapstructure:"cert_file" yaml:"-"`
+	CertKey                   string        `json:"-" mapstructure:"cert_key" yaml:"-"`
+	GRPCConnectionMaxIdleTime time.Duration `json:"-" mapstructure:"grpc_conn_max_idle_time" yaml:"-"`
+	GRPCConnectionMaxAge      time.Duration `json:"-" mapstructure:"grpc_conn_max_age" yaml:"-"`
+	GRPCConnectionMaxAgeGrace time.Duration `json:"-" mapstructure:"grpc_conn_max_age_grace" yaml:"-"`
 }
 
 func (c *ServerConfig) setDefaults(v *viper.Viper) error {

internal/config/testdata/server/grpc_keepalive.yml

@@ -0,0 +1,30 @@
+# log:
+#   level: INFO
+#   grpc_level: ERROR
+
+# ui:
+#   enabled: true
+
+# cors:
+#   enabled: false
+#   allowed_origins: "*"
+
+# cache:
+#   enabled: false
+#   backend: memory
+#   ttl: 60s
+#   memory:
+#     eviction_interval: 5m # Evict Expired Items Every 5m
+
+server:
+#   protocol: https
+#   host: 0.0.0.0
+#   https_port: 443
+#   http_port: 8080
+#   grpc_port: 9000
+    grpc_conn_max_idle_time: 1h
+    grpc_conn_max_age: 30s
+    grpc_conn_max_age_grace: 10s
+
+# db:
+#   url: file:/var/opt/flipt/flipt.db