refactor(config): drops localhost rewrite

cmd/sentry/main.go

@@ -422,7 +422,7 @@ func (s *contributoor) initBeaconNode() error {
 	b, err := ethereum.NewBeaconNode(
 		s.log,
 		&ethereum.Config{
-			BeaconNodeAddress:   s.config.NodeAddress(),
+			BeaconNodeAddress:   s.config.BeaconNodeAddress,
 			OverrideNetworkName: s.name,
 		},
 		s.name,

pkg/config/v1/config.go

@@ -19,28 +19,6 @@ const (
 	defaultPprofPort   = "6060"
 )
 
-var localHostnames = map[string]bool{
-	"localhost": true,
-	"127.0.0.1": true,
-	"0.0.0.0":   true,
-}
-
-// isRunningInDocker checks if we're actually running inside a Docker container
-// by looking for container-specific files and environment variables.
-var isRunningInDocker = func() bool {
-	// Check for .dockerenv file.
-	if _, err := os.Stat("/.dockerenv"); err == nil {
-		return true
-	}
-
-	// Check for docker-specific cgroup.
-	if data, err := os.ReadFile("/proc/1/cgroup"); err == nil {
-		return strings.Contains(string(data), "docker")
-	}
-
-	return false
-}
-
 // NewConfigFromPath loads a config from a YAML file and validates it.
 func NewConfigFromPath(path string) (*Config, error) {
 	data, err := os.ReadFile(path)
@@ -173,35 +151,6 @@ func (c *Config) GetPprofHostPort() (host, port string) {
 	return ParseAddress(c.PprofAddress, defaultPprofHost, defaultPprofPort)
 }
 
-// NodeAddress returns the beacon node address, rewriting local addresses
-// to use host.docker.internal when running in Docker.
-// Docker containers can't directly access the host via localhost/127.0.0.1.
-// We rewrite these to host.docker.internal which resolves differently per platform:
-// - macOS: Built-in DNS name that points to the Docker Desktop VM's gateway
-// - Linux: Maps to host-gateway via extra_hosts in docker-compose.yml
-// This provides a consistent way to access the host machine across platforms.
-func (c *Config) NodeAddress() string {
-	// Only rewrite if:
-	// 1. We have a beacon node address.
-	// 2. Docker is configured as the run method.
-	// 3. We're actually running inside a Docker container.
-	if c.BeaconNodeAddress == "" ||
-		c.RunMethod != RunMethod_RUN_METHOD_DOCKER ||
-		!isRunningInDocker() {
-		return c.BeaconNodeAddress
-	}
-
-	// Check if URL points to a local address.
-	for hostname := range localHostnames {
-		if strings.Contains(c.BeaconNodeAddress, hostname) {
-			// Replace the local hostname with host.docker.internal.
-			return strings.Replace(c.BeaconNodeAddress, hostname, "host.docker.internal", 1)
-		}
-	}
-
-	return c.BeaconNodeAddress
-}
-
 // SetNetwork sets the network name.
 func (c *Config) SetNetwork(network string) {
 	if network == "" {

pkg/config/v1/config_test.go

@@ -244,99 +244,3 @@ func TestConfig_GetPprofHostPort(t *testing.T) {
 		})
 	}
 }
-
-func TestConfig_NodeAddress(t *testing.T) {
-	// Mock isRunningInDocker for testing
-	originalIsRunningInDocker := isRunningInDocker
-	defer func() { isRunningInDocker = originalIsRunningInDocker }()
-
-	tests := []struct {
-		name            string
-		config          *Config
-		inDocker        bool
-		expectedAddress string
-	}{
-		{
-			name: "docker mode + in docker container + local url",
-			config: &Config{
-				BeaconNodeAddress: "http://localhost:5052",
-				RunMethod:         RunMethod_RUN_METHOD_DOCKER,
-			},
-			inDocker:        true,
-			expectedAddress: "http://host.docker.internal:5052",
-		},
-		{
-			name: "docker mode + in docker container + 127.0.0.1",
-			config: &Config{
-				BeaconNodeAddress: "http://127.0.0.1:5052",
-				RunMethod:         RunMethod_RUN_METHOD_DOCKER,
-			},
-			inDocker:        true,
-			expectedAddress: "http://host.docker.internal:5052",
-		},
-		{
-			name: "docker mode + in docker container + 0.0.0.0",
-			config: &Config{
-				BeaconNodeAddress: "http://0.0.0.0:5052",
-				RunMethod:         RunMethod_RUN_METHOD_DOCKER,
-			},
-			inDocker:        true,
-			expectedAddress: "http://host.docker.internal:5052",
-		},
-		{
-			name: "docker mode + in docker container + remote url",
-			config: &Config{
-				BeaconNodeAddress: "http://example.com:5052",
-				RunMethod:         RunMethod_RUN_METHOD_DOCKER,
-			},
-			inDocker:        true,
-			expectedAddress: "http://example.com:5052",
-		},
-		{
-			name: "docker mode + NOT in docker + local url",
-			config: &Config{
-				BeaconNodeAddress: "http://localhost:5052",
-				RunMethod:         RunMethod_RUN_METHOD_DOCKER,
-			},
-			inDocker:        false,
-			expectedAddress: "http://localhost:5052",
-		},
-		{
-			name: "non-docker mode + in docker + local url",
-			config: &Config{
-				BeaconNodeAddress: "http://localhost:5052",
-				RunMethod:         RunMethod_RUN_METHOD_BINARY,
-			},
-			inDocker:        true,
-			expectedAddress: "http://localhost:5052",
-		},
-		{
-			name: "docker mode + in docker + local url with path",
-			config: &Config{
-				BeaconNodeAddress: "http://localhost:5052/eth/v1/node/syncing",
-				RunMethod:         RunMethod_RUN_METHOD_DOCKER,
-			},
-			inDocker:        true,
-			expectedAddress: "http://host.docker.internal:5052/eth/v1/node/syncing",
-		},
-		{
-			name: "empty address",
-			config: &Config{
-				BeaconNodeAddress: "",
-				RunMethod:         RunMethod_RUN_METHOD_DOCKER,
-			},
-			inDocker:        true,
-			expectedAddress: "",
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			// Mock isRunningInDocker for this test
-			isRunningInDocker = func() bool { return tt.inDocker }
-
-			got := tt.config.NodeAddress()
-			assert.Equal(t, tt.expectedAddress, got)
-		})
-	}
-}