TUN-1952: Group ClientConfig fields by the component that uses the config, and return the part of the config that failed to be applied

h2mux/muxedstream.go

@@ -77,6 +77,16 @@ type MuxedStream struct {
 	dictionaries    h2Dictionaries
 }
 
+type TunnelHostname string
+
+func (th TunnelHostname) String() string {
+	return string(th)
+}
+
+func (th TunnelHostname) IsSet() bool {
+	return th != ""
+}
+
 func (s *MuxedStream) Read(p []byte) (n int, err error) {
 	var readBuffer ReadWriteClosedCloser
 	if s.dictionaries.read != nil {

tunnelrpc/pogs/config.go

@@ -10,6 +10,7 @@ import (
 	"net/url"
 	"time"
 
+	"github.com/cloudflare/cloudflared/h2mux"
 	"github.com/cloudflare/cloudflared/originservice"
 	"github.com/cloudflare/cloudflared/tlsconfig"
 	"github.com/cloudflare/cloudflared/tunnelrpc"
@@ -17,37 +18,82 @@ import (
 	capnp "zombiezen.com/go/capnproto2"
 	"zombiezen.com/go/capnproto2/pogs"
 	"zombiezen.com/go/capnproto2/rpc"
+	"zombiezen.com/go/capnproto2/server"
 )
 
 ///
 /// Structs
 ///
 
+// ClientConfig is a collection of FallibleConfig that determines how cloudflared should function
 type ClientConfig struct {
-	Version                uint64
+	Version              Version
+	SupervisorConfig     *SupervisorConfig
+	EdgeConnectionConfig *EdgeConnectionConfig
+	DoHProxyConfigs      []*DoHProxyConfig
+	ReverseProxyConfigs  []*ReverseProxyConfig
+}
+
+// Version type models the version of a ClientConfig
+type Version uint64
+
+func InitVersion() Version {
+	return Version(0)
+}
+
+func (v Version) IsNewerOrEqual(comparedVersion Version) bool {
+	return v >= comparedVersion
+}
+
+func (v Version) String() string {
+	return fmt.Sprintf("Version: %d", v)
+}
+
+// FallibleConfig is an interface implemented by configs that cloudflared might not be able to apply
+type FallibleConfig interface {
+	FailReason(err error) string
+}
+
+// SupervisorConfig specifies config of components managed by Supervisor other than ConnectionManager
+type SupervisorConfig struct {
 	AutoUpdateFrequency    time.Duration
 	MetricsUpdateFrequency time.Duration
-	HeartbeatInterval      time.Duration
-	MaxFailedHeartbeats    uint64
 	GracePeriod            time.Duration
-	DoHProxyConfigs        []*DoHProxyConfig
-	ReverseProxyConfigs    []*ReverseProxyConfig
-	NumHAConnections       uint8
 }
 
-type UseConfigurationResult struct {
+// FailReason impelents FallibleConfig interface for SupervisorConfig
-	Success      bool
+func (sc *SupervisorConfig) FailReason(err error) string {
-	ErrorMessage string
+	return fmt.Sprintf("Cannot apply SupervisorConfig, err: %v", err)
 }
 
+// EdgeConnectionConfig specifies what parameters and how may connections should ConnectionManager establish with edge
+type EdgeConnectionConfig struct {
+	NumHAConnections    uint8
+	HeartbeatInterval   time.Duration
+	Timeout             time.Duration
+	MaxFailedHeartbeats uint64
+}
+
+// FailReason impelents FallibleConfig interface for EdgeConnectionConfig
+func (cmc *EdgeConnectionConfig) FailReason(err error) string {
+	return fmt.Sprintf("Cannot apply EdgeConnectionConfig, err: %v", err)
+}
+
+// DoHProxyConfig is configuration for DNS over HTTPS service
 type DoHProxyConfig struct {
 	ListenHost string
 	ListenPort uint16
 	Upstreams  []string
 }
 
+// FailReason impelents FallibleConfig interface for DoHProxyConfig
+func (dpc *DoHProxyConfig) FailReason(err error) string {
+	return fmt.Sprintf("Cannot apply DoHProxyConfig, err: %v", err)
+}
+
+// ReverseProxyConfig how and for what hostnames can this cloudflared proxy
 type ReverseProxyConfig struct {
-	TunnelHostname     string
+	TunnelHostname     h2mux.TunnelHostname
 	Origin             OriginConfig
 	Retries            uint64
 	ConnectionTimeout  time.Duration
@@ -65,7 +111,7 @@ func NewReverseProxyConfig(
 		return nil, fmt.Errorf("NewReverseProxyConfig: originConfig was null")
 	}
 	return &ReverseProxyConfig{
-		TunnelHostname:     tunnelHostname,
+		TunnelHostname:     h2mux.TunnelHostname(tunnelHostname),
 		Origin:             originConfig,
 		Retries:            retries,
 		ConnectionTimeout:  connectionTimeout,
@@ -73,6 +119,11 @@ func NewReverseProxyConfig(
 	}, nil
 }
 
+// FailReason impelents FallibleConfig interface for ReverseProxyConfig
+func (rpc *ReverseProxyConfig) FailReason(err error) string {
+	return fmt.Sprintf("Cannot apply ReverseProxyConfig, err: %v", err)
+}
+
 //go-sumtype:decl OriginConfig
 type OriginConfig interface {
 	// Service returns a OriginService used to proxy to the origin
@@ -221,18 +272,45 @@ func (_ *HelloWorldOriginConfig) isOriginConfig() {}
  */
 
 func MarshalClientConfig(s tunnelrpc.ClientConfig, p *ClientConfig) error {
-	s.SetVersion(p.Version)
+	s.SetVersion(uint64(p.Version))
-	s.SetAutoUpdateFrequency(p.AutoUpdateFrequency.Nanoseconds())
+
-	s.SetMetricsUpdateFrequency(p.MetricsUpdateFrequency.Nanoseconds())
+	supervisorConfig, err := s.NewSupervisorConfig()
-	s.SetHeartbeatInterval(p.HeartbeatInterval.Nanoseconds())
-	s.SetMaxFailedHeartbeats(p.MaxFailedHeartbeats)
-	s.SetGracePeriod(p.GracePeriod.Nanoseconds())
-	s.SetNumHAConnections(p.NumHAConnections)
-	err := marshalDoHProxyConfigs(s, p.DoHProxyConfigs)
 	if err != nil {
-		return err
+		return errors.Wrap(err, "failed to get SupervisorConfig")
 	}
-	return marshalReverseProxyConfigs(s, p.ReverseProxyConfigs)
+	if err = MarshalSupervisorConfig(supervisorConfig, p.SupervisorConfig); err != nil {
+		return errors.Wrap(err, "MarshalSupervisorConfig error")
+	}
+
+	edgeConnectionConfig, err := s.NewEdgeConnectionConfig()
+	if err != nil {
+		return errors.Wrap(err, "failed to get EdgeConnectionConfig")
+	}
+	if err := MarshalEdgeConnectionConfig(edgeConnectionConfig, p.EdgeConnectionConfig); err != nil {
+		return errors.Wrap(err, "MarshalEdgeConnectionConfig error")
+	}
+
+	if err := marshalDoHProxyConfigs(s, p.DoHProxyConfigs); err != nil {
+		return errors.Wrap(err, "marshalDoHProxyConfigs error")
+	}
+	if err := marshalReverseProxyConfigs(s, p.ReverseProxyConfigs); err != nil {
+		return errors.Wrap(err, "marshalReverseProxyConfigs error")
+	}
+	return nil
+}
+
+func MarshalSupervisorConfig(s tunnelrpc.SupervisorConfig, p *SupervisorConfig) error {
+	if err := pogs.Insert(tunnelrpc.SupervisorConfig_TypeID, s.Struct, p); err != nil {
+		return errors.Wrap(err, "failed to insert SupervisorConfig")
+	}
+	return nil
+}
+
+func MarshalEdgeConnectionConfig(s tunnelrpc.EdgeConnectionConfig, p *EdgeConnectionConfig) error {
+	if err := pogs.Insert(tunnelrpc.EdgeConnectionConfig_TypeID, s.Struct, p); err != nil {
+		return errors.Wrap(err, "failed to insert EdgeConnectionConfig")
+	}
+	return nil
 }
 
 func marshalDoHProxyConfigs(s tunnelrpc.ClientConfig, dohProxyConfigs []*DoHProxyConfig) error {
@@ -265,23 +343,48 @@ func marshalReverseProxyConfigs(s tunnelrpc.ClientConfig, reverseProxyConfigs []
 
 func UnmarshalClientConfig(s tunnelrpc.ClientConfig) (*ClientConfig, error) {
 	p := new(ClientConfig)
-	p.Version = s.Version()
+	p.Version = Version(s.Version())
-	p.AutoUpdateFrequency = time.Duration(s.AutoUpdateFrequency())
+
-	p.MetricsUpdateFrequency = time.Duration(s.MetricsUpdateFrequency())
+	supervisorConfig, err := s.SupervisorConfig()
-	p.HeartbeatInterval = time.Duration(s.HeartbeatInterval())
-	p.MaxFailedHeartbeats = s.MaxFailedHeartbeats()
-	p.GracePeriod = time.Duration(s.GracePeriod())
-	p.NumHAConnections = s.NumHAConnections()
-	dohProxyConfigs, err := unmarshalDoHProxyConfigs(s)
 	if err != nil {
-		return nil, err
+		return nil, errors.Wrap(err, "failed to get SupervisorConfig")
 	}
-	p.DoHProxyConfigs = dohProxyConfigs
+	p.SupervisorConfig, err = UnmarshalSupervisorConfig(supervisorConfig)
-	reverseProxyConfigs, err := unmarshalReverseProxyConfigs(s)
 	if err != nil {
-		return nil, err
+		return nil, errors.Wrap(err, "UnmarshalSupervisorConfig error")
 	}
-	p.ReverseProxyConfigs = reverseProxyConfigs
+
+	edgeConnectionConfig, err := s.EdgeConnectionConfig()
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to get ConnectionManagerConfig")
+	}
+	p.EdgeConnectionConfig, err = UnmarshalEdgeConnectionConfig(edgeConnectionConfig)
+	if err != nil {
+		return nil, errors.Wrap(err, "UnmarshalConnectionManagerConfig error")
+	}
+
+	p.DoHProxyConfigs, err = unmarshalDoHProxyConfigs(s)
+	if err != nil {
+		return nil, errors.Wrap(err, "unmarshalDoHProxyConfigs error")
+	}
+
+	p.ReverseProxyConfigs, err = unmarshalReverseProxyConfigs(s)
+	if err != nil {
+		return nil, errors.Wrap(err, "unmarshalReverseProxyConfigs error")
+	}
+
+	return p, nil
+}
+
+func UnmarshalSupervisorConfig(s tunnelrpc.SupervisorConfig) (*SupervisorConfig, error) {
+	p := new(SupervisorConfig)
+	err := pogs.Extract(p, tunnelrpc.SupervisorConfig_TypeID, s.Struct)
+	return p, err
+}
+
+func UnmarshalEdgeConnectionConfig(s tunnelrpc.EdgeConnectionConfig) (*EdgeConnectionConfig, error) {
+	p := new(EdgeConnectionConfig)
+	err := pogs.Extract(p, tunnelrpc.EdgeConnectionConfig_TypeID, s.Struct)
 	return p, err
 }
 
@@ -320,13 +423,38 @@ func unmarshalReverseProxyConfigs(s tunnelrpc.ClientConfig) ([]*ReverseProxyConf
 }
 
 func MarshalUseConfigurationResult(s tunnelrpc.UseConfigurationResult, p *UseConfigurationResult) error {
-	return pogs.Insert(tunnelrpc.UseConfigurationResult_TypeID, s.Struct, p)
+	capnpList, err := s.NewFailedConfigs(int32(len(p.FailedConfigs)))
+	if err != nil {
+		return errors.Wrap(err, "Cannot create new FailedConfigs")
+	}
+	for i, unmarshalledFailedConfig := range p.FailedConfigs {
+		err := MarshalFailedConfig(capnpList.At(i), unmarshalledFailedConfig)
+		if err != nil {
+			return errors.Wrapf(err, "Cannot MarshalFailedConfig at index %d", i)
+		}
+	}
+	s.SetSuccess(p.Success)
+	return nil
 }
 
 func UnmarshalUseConfigurationResult(s tunnelrpc.UseConfigurationResult) (*UseConfigurationResult, error) {
 	p := new(UseConfigurationResult)
-	err := pogs.Extract(p, tunnelrpc.UseConfigurationResult_TypeID, s.Struct)
+	var failedConfigs []*FailedConfig
-	return p, err
+	marshalledFailedConfigs, err := s.FailedConfigs()
+	if err != nil {
+		return nil, errors.Wrap(err, "Cannot get FailedConfigs")
+	}
+	for i := 0; i < marshalledFailedConfigs.Len(); i++ {
+		ss := marshalledFailedConfigs.At(i)
+		failedConfig, err := UnmarshalFailedConfig(ss)
+		if err != nil {
+			return nil, errors.Wrapf(err, "Cannot UnmarshalFailedConfig at index %d", i)
+		}
+		failedConfigs = append(failedConfigs, failedConfig)
+	}
+	p.FailedConfigs = failedConfigs
+	p.Success = s.Success()
+	return p, nil
 }
 
 func MarshalDoHProxyConfig(s tunnelrpc.DoHProxyConfig, p *DoHProxyConfig) error {
@@ -340,7 +468,7 @@ func UnmarshalDoHProxyConfig(s tunnelrpc.DoHProxyConfig) (*DoHProxyConfig, error
 }
 
 func MarshalReverseProxyConfig(s tunnelrpc.ReverseProxyConfig, p *ReverseProxyConfig) error {
-	s.SetTunnelHostname(p.TunnelHostname)
+	s.SetTunnelHostname(p.TunnelHostname.String())
 	switch config := p.Origin.(type) {
 	case *HTTPOriginConfig:
 		ss, err := s.Origin().NewHttp()
@@ -381,7 +509,7 @@ func UnmarshalReverseProxyConfig(s tunnelrpc.ReverseProxyConfig) (*ReverseProxyC
 	if err != nil {
 		return nil, err
 	}
-	p.TunnelHostname = tunnelHostname
+	p.TunnelHostname = h2mux.TunnelHostname(tunnelHostname)
 	switch s.Origin().Which() {
 	case tunnelrpc.ReverseProxyConfig_origin_Which_http:
 		ss, err := s.Origin().Http()
@@ -584,3 +712,141 @@ func (c *ClientService_PogsClient) UseConfiguration(
 	}
 	return UnmarshalUseConfigurationResult(retval)
 }
+
+func ClientService_ServerToClient(s ClientService) tunnelrpc.ClientService {
+	return tunnelrpc.ClientService_ServerToClient(ClientService_PogsImpl{s})
+}
+
+type ClientService_PogsImpl struct {
+	impl ClientService
+}
+
+func (i ClientService_PogsImpl) UseConfiguration(p tunnelrpc.ClientService_useConfiguration) error {
+	config, err := p.Params.ClientServiceConfig()
+	if err != nil {
+		return errors.Wrap(err, "Cannot get CloudflaredConfig parameter")
+	}
+	pogsConfig, err := UnmarshalClientConfig(config)
+	if err != nil {
+		return errors.Wrap(err, "Cannot unmarshal tunnelrpc.CloudflaredConfig to *CloudflaredConfig")
+	}
+	server.Ack(p.Options)
+	userConfigResult, err := i.impl.UseConfiguration(p.Ctx, pogsConfig)
+	if err != nil {
+		return err
+	}
+	result, err := p.Results.NewResult()
+	if err != nil {
+		return err
+	}
+	return MarshalUseConfigurationResult(result, userConfigResult)
+}
+
+type UseConfigurationResult struct {
+	Success       bool
+	FailedConfigs []*FailedConfig
+}
+
+type FailedConfig struct {
+	Config FallibleConfig
+	Reason string
+}
+
+func MarshalFailedConfig(s tunnelrpc.FailedConfig, p *FailedConfig) error {
+	switch config := p.Config.(type) {
+	case *SupervisorConfig:
+		ss, err := s.Config().NewSupervisor()
+		if err != nil {
+			return err
+		}
+		err = MarshalSupervisorConfig(ss, config)
+		if err != nil {
+			return err
+		}
+	case *EdgeConnectionConfig:
+		ss, err := s.Config().EdgeConnection()
+		if err != nil {
+			return err
+		}
+		err = MarshalEdgeConnectionConfig(ss, config)
+		if err != nil {
+			return err
+		}
+	case *DoHProxyConfig:
+		ss, err := s.Config().NewDoh()
+		if err != nil {
+			return err
+		}
+		err = MarshalDoHProxyConfig(ss, config)
+		if err != nil {
+			return err
+		}
+	case *ReverseProxyConfig:
+		ss, err := s.Config().NewReverseProxy()
+		if err != nil {
+			return err
+		}
+		err = MarshalReverseProxyConfig(ss, config)
+		if err != nil {
+			return err
+		}
+	default:
+		return fmt.Errorf("Unknown type for Config: %T", config)
+	}
+	s.SetReason(p.Reason)
+	return nil
+}
+
+func UnmarshalFailedConfig(s tunnelrpc.FailedConfig) (*FailedConfig, error) {
+	p := new(FailedConfig)
+	switch s.Config().Which() {
+	case tunnelrpc.FailedConfig_config_Which_supervisor:
+		ss, err := s.Config().Supervisor()
+		if err != nil {
+			return nil, errors.Wrap(err, "Cannot get SupervisorConfig from Config")
+		}
+		config, err := UnmarshalSupervisorConfig(ss)
+		if err != nil {
+			return nil, errors.Wrap(err, "Cannot UnmarshalSupervisorConfig")
+		}
+		p.Config = config
+	case tunnelrpc.FailedConfig_config_Which_edgeConnection:
+		ss, err := s.Config().EdgeConnection()
+		if err != nil {
+			return nil, errors.Wrap(err, "Cannot get ConnectionManager from Config")
+		}
+		config, err := UnmarshalEdgeConnectionConfig(ss)
+		if err != nil {
+			return nil, errors.Wrap(err, "Cannot UnmarshalConnectionManagerConfig")
+		}
+		p.Config = config
+	case tunnelrpc.FailedConfig_config_Which_doh:
+		ss, err := s.Config().Doh()
+		if err != nil {
+			return nil, errors.Wrap(err, "Cannot get Doh from Config")
+		}
+		config, err := UnmarshalDoHProxyConfig(ss)
+		if err != nil {
+			return nil, errors.Wrap(err, "Cannot UnmarshalDoHProxyConfig")
+		}
+		p.Config = config
+	case tunnelrpc.FailedConfig_config_Which_reverseProxy:
+		ss, err := s.Config().ReverseProxy()
+		if err != nil {
+			return nil, errors.Wrap(err, "Cannot get ReverseProxy from Config")
+		}
+		config, err := UnmarshalReverseProxyConfig(ss)
+		if err != nil {
+			return nil, errors.Wrap(err, "Cannot UnmarshalReverseProxyConfig")
+		}
+		p.Config = config
+	default:
+		return nil, fmt.Errorf("Unknown type for FailedConfig: %v", s.Config().Which())
+	}
+	reason, err := s.Reason()
+	if err != nil {
+		return nil, errors.Wrap(err, "Cannot get Reason")
+	}
+	p.Reason = reason
+	return p, nil
+}

tunnelrpc/pogs/config_test.go

@@ -13,6 +13,14 @@ import (
 	capnp "zombiezen.com/go/capnproto2"
 )
 
+func TestVersion(t *testing.T) {
+	firstVersion := InitVersion()
+	secondVersion := Version(1)
+	assert.False(t, firstVersion.IsNewerOrEqual(secondVersion))
+	assert.True(t, secondVersion.IsNewerOrEqual(firstVersion))
+	assert.True(t, secondVersion.IsNewerOrEqual(secondVersion))
+}
+
 func TestClientConfig(t *testing.T) {
 	addDoHProxyConfigs := func(c *ClientConfig) {
 		c.DoHProxyConfigs = []*DoHProxyConfig{
@@ -66,8 +74,17 @@ func TestUseConfigurationResult(t *testing.T) {
 			Success: true,
 		},
 		&UseConfigurationResult{
-			Success:      false,
+			Success: false,
-			ErrorMessage: "the quick brown fox jumped over the lazy dogs",
+			FailedConfigs: []*FailedConfig{
+				{
+					Config: sampleReverseProxyConfig(),
+					Reason: "Invalid certificate",
+				},
+				{
+					Config: sampleDoHProxyConfig(),
+					Reason: "Cannot listen on port 53",
+				},
+			},
 		},
 	}
 	for i, testCase := range testCases {
@@ -193,13 +210,18 @@ func TestWebSocketOriginConfig(t *testing.T) {
 
 func sampleClientConfig(overrides ...func(*ClientConfig)) *ClientConfig {
 	sample := &ClientConfig{
-		Version:                uint64(1337),
+		Version: Version(1337),
-		AutoUpdateFrequency:    21 * time.Hour,
+		SupervisorConfig: &SupervisorConfig{
-		MetricsUpdateFrequency: 11 * time.Minute,
+			AutoUpdateFrequency:    21 * time.Hour,
-		HeartbeatInterval:      5 * time.Second,
+			MetricsUpdateFrequency: 11 * time.Minute,
-		MaxFailedHeartbeats:    9001,
+			GracePeriod:            31 * time.Second,
-		GracePeriod:            31 * time.Second,
+		},
-		NumHAConnections:       49,
+		EdgeConnectionConfig: &EdgeConnectionConfig{
+			NumHAConnections:    49,
+			Timeout:             9 * time.Second,
+			HeartbeatInterval:   5 * time.Second,
+			MaxFailedHeartbeats: 9001,
+		},
 	}
 	sample.ensureNoZeroFields()
 	for _, f := range overrides {

tunnelrpc/tunnelrpc.capnp

@@ -77,35 +77,46 @@ struct ClientConfig {
     # to monotonically increase in value. Any configuration supplied to
     # useConfiguration() with a smaller `version` should be ignored.
     version @0 :UInt64;
+    # supervisorConfig  is configuration for supervisor, the component that manages connection manager,
+    # autoupdater and metrics server
+    supervisorConfig @1 :SupervisorConfig;
+    # edgeConnectionConfig is configuration for connection manager, the componenet that manages connections with the edge
+    edgeConnectionConfig @2 :EdgeConnectionConfig;
+    # Configuration for cloudflared to run as a DNS-over-HTTPS proxy.
+    # cloudflared CLI option: `proxy-dns`
+    dohProxyConfigs @3 :List(DoHProxyConfig);
+    # Configuration for cloudflared to run as an HTTP reverse proxy.
+    reverseProxyConfigs @4 :List(ReverseProxyConfig);
+}
+
+struct SupervisorConfig {
     # Frequency (in ns) to check Equinox for updates.
     # Zero means auto-update is disabled.
     # cloudflared CLI option: `autoupdate-freq`
-    autoUpdateFrequency @1 :Int64;
+    autoUpdateFrequency @0 :Int64;
     # Frequency (in ns) to update connection-based metrics.
     # cloudflared CLI option: `metrics-update-freq`
-    metricsUpdateFrequency @2 :Int64;
+    metricsUpdateFrequency @1 :Int64;
-    # interval (in ns) between heartbeats with the Cloudflare edge
-    # cloudflared CLI option: `heartbeat-interval`
-    heartbeatInterval @3 :Int64;
-    # Minimum number of unacked heartbeats for cloudflared to send before
-    # closing the connection to the edge.
-    # cloudflared CLI option: `heartbeat-count`
-    maxFailedHeartbeats @4 :UInt64;
     # Time (in ns) to continue serving requests after cloudflared receives its
     # first SIGINT/SIGTERM. A second SIGINT/SIGTERM will force cloudflared to
     # shutdown immediately. For example, this field can be used to gracefully
     # transition traffic to another cloudflared instance.
     # cloudflared CLI option: `grace-period`
-    gracePeriod @5 :Int64;
+    gracePeriod @2 :Int64;
-    # Configuration for cloudflared to run as a DNS-over-HTTPS proxy.
+}
-    # cloudflared CLI option: `proxy-dns`
+
-    dohProxyConfigs @6 :List(DoHProxyConfig);
+struct EdgeConnectionConfig {
-    # Configuration for cloudflared to run as an HTTP reverse proxy.
-    reverseProxyConfigs @7 :List(ReverseProxyConfig);
-    # Number of persistent connections to keep open between cloudflared and
-    # the edge.
     # cloudflared CLI option: `ha-connections`
-    numHAConnections @8 :UInt8;
+    numHAConnections @0 :UInt8;
+    # Interval (in ns) between heartbeats with the Cloudflare edge
+    # cloudflared CLI option: `heartbeat-interval`
+    heartbeatInterval @1 :Int64;
+    # Maximum wait time to connect with the edge.
+    timeout  @2 :Int64;
+    # Number of unacked heartbeats for cloudflared to send before
+    # closing the connection to the edge.
+    # cloudflared CLI option: `heartbeat-count`
+    maxFailedHeartbeats @3 :UInt64;
 }
 
 struct ReverseProxyConfig {
@@ -251,7 +262,17 @@ struct ServerInfo {
 
 struct UseConfigurationResult {
     success @0 :Bool;
-    errorMessage @1 :Text;
+    failedConfigs @1 :List(FailedConfig);
+}
+
+struct FailedConfig {
+    config :union {
+        supervisor @0 :SupervisorConfig;
+        edgeConnection @1 :EdgeConnectionConfig;
+        doh @2 :DoHProxyConfig;
+        reverseProxy @3 :ReverseProxyConfig;
+    }
+	reason @4 :Text;
 }
 
 interface TunnelServer {