Init data collect protocol from SkyWalking 5.0.0-alpha develop branch.

ApplicationRegisterService.proto

+syntax = "proto3";
+
+option java_multiple_files = true;
+option java_package = "org.apache.skywalking.apm.network.proto";
+
+import "KeyWithIntegerValue.proto";
+
+//register service for ApplicationCode, this service is called when service starts.
+service ApplicationRegisterService {
+    rpc applicationCodeRegister (Application) returns (ApplicationMapping) {
+    }
+}
+
+message Application {
+    string applicationCode = 1;
+}
+
+message ApplicationMapping {
+    KeyWithIntegerValue application = 1;
+}

Common.proto

+syntax = "proto3";
+
+option java_multiple_files = true;
+option java_package = "org.apache.skywalking.apm.network.proto";
+
+enum SpanType {
+    Entry = 0;
+    Exit = 1;
+    Local = 2;
+}
\ No newline at end of file

DiscoveryService.proto

+syntax = "proto3";
+
+option java_multiple_files = true;
+option java_package = "org.apache.skywalking.apm.network.proto";
+
+import "Common.proto";
+import "Downstream.proto";
+
+service InstanceDiscoveryService {
+    rpc registerInstance (ApplicationInstance) returns (ApplicationInstanceMapping) {
+    }
+
+    rpc heartbeat (ApplicationInstanceHeartbeat) returns (Downstream) {
+    }
+
+}
+
+message ApplicationInstance {
+    int32 applicationId = 1;
+    string agentUUID = 2;
+    int64 registerTime = 3;
+    OSInfo osinfo = 4;
+}
+
+message ApplicationInstanceMapping {
+    int32 applicationId = 1;
+    int32 applicationInstanceId = 2;
+}
+
+message ApplicationInstanceRecover {
+    int32 applicationId = 1;
+    int32 applicationInstanceId = 2;
+    int64 registerTime = 3;
+    OSInfo osinfo = 4;
+}
+
+message ApplicationInstanceHeartbeat {
+    int32 applicationInstanceId = 1;
+    int64 heartbeatTime = 2;
+}
+
+message OSInfo {
+    string osName = 1;
+    string hostname = 2;
+    int32 processNo = 3;
+    repeated string ipv4s = 4;
+}
+
+//discovery service for ServiceName by Network address or application code
+service ServiceNameDiscoveryService {
+    rpc discovery (ServiceNameCollection) returns (ServiceNameMappingCollection) {
+    }
+}
+
+message ServiceNameCollection {
+    repeated ServiceNameElement elements = 1;
+}
+
+message ServiceNameMappingCollection {
+    repeated ServiceNameMappingElement elements = 1;
+}
+
+message ServiceNameMappingElement {
+    int32 serviceId = 1;
+    ServiceNameElement element = 2;
+}
+
+message ServiceNameElement {
+    string serviceName = 1;
+    int32 applicationId = 2;
+    SpanType srcSpanType = 3;
+}

Downstream.proto

+syntax = "proto3";
+
+option java_multiple_files = true;
+option java_package = "org.apache.skywalking.apm.network.proto";
+
+// nothing down stream from collector yet.
+message Downstream {
+}

JVMMetricsService.proto

+syntax = "proto3";
+
+option java_multiple_files = true;
+option java_package = "org.apache.skywalking.apm.network.proto";
+
+import "Downstream.proto";
+
+service JVMMetricsService {
+    rpc collect (JVMMetrics) returns (Downstream) {
+    }
+}
+
+message JVMMetrics {
+    repeated JVMMetric metrics = 1;
+    int32 applicationInstanceId = 2;
+}
+
+message JVMMetric {
+    int64 time = 1;
+    CPU cpu = 2;
+    repeated Memory memory = 3;
+    repeated MemoryPool memoryPool = 4;
+    repeated GC gc = 5;
+}
+
+message CPU {
+    double usagePercent = 2;
+}
+
+message Memory {
+    bool isHeap = 1;
+    int64 init = 2;
+    int64 max = 3;
+    int64 used = 4;
+    int64 committed = 5;
+}
+
+message MemoryPool {
+    PoolType type = 1;
+    int64 init = 2;
+    int64 max = 3;
+    int64 used = 4;
+    int64 commited = 5;
+}
+
+enum PoolType {
+    CODE_CACHE_USAGE = 0;
+    NEWGEN_USAGE = 1;
+    OLDGEN_USAGE = 2;
+    SURVIVOR_USAGE = 3;
+    PERMGEN_USAGE = 4;
+    METASPACE_USAGE = 5;
+}
+
+message GC {
+    GCPhrase phrase = 1;
+    int64 count = 2;
+    int64 time = 3;
+}
+
+enum GCPhrase {
+    NEW = 0;
+    OLD = 1;
+}

KeyWithIntegerValue.proto

+syntax = "proto3";
+
+option java_multiple_files = true;
+option java_package = "org.apache.skywalking.apm.network.proto";
+
+message KeyWithIntegerValue {
+    string key = 1;
+    int32 value = 2;
+}

KeyWithStringValue.proto

+syntax = "proto3";
+
+option java_multiple_files = true;
+option java_package = "org.apache.skywalking.apm.network.proto";
+
+message KeyWithStringValue {
+    string key = 1;
+    string value = 2;
+}

NetworkAddressRegisterService.proto

+syntax = "proto3";
+
+option java_multiple_files = true;
+option java_package = "org.apache.skywalking.apm.network.proto";
+
+import "KeyWithIntegerValue.proto";
+
+service NetworkAddressRegisterService {
+    rpc batchRegister (NetworkAddresses) returns (NetworkAddressMappings) {
+    }
+}
+
+message NetworkAddresses {
+    repeated string addresses = 1;
+}
+
+message NetworkAddressMappings {
+    repeated KeyWithIntegerValue addressIds = 1;
+}

TraceSegmentService.proto

+syntax = "proto3";
+
+option java_multiple_files = true;
+option java_package = "org.apache.skywalking.apm.network.proto";
+
+import "Common.proto";
+import "Downstream.proto";
+import "KeyWithStringValue.proto";
+
+service TraceSegmentService {
+    rpc collect (stream UpstreamSegment) returns (Downstream) {
+    }
+}
+
+message UpstreamSegment {
+    repeated UniqueId globalTraceIds = 1;
+    bytes segment = 2; // the byte array of TraceSegmentObject
+}
+
+message UniqueId {
+    repeated int64 idParts = 1;
+}
+
+message TraceSegmentObject {
+    UniqueId traceSegmentId = 1;
+    repeated SpanObject spans = 2;
+    int32 applicationId = 3;
+    int32 applicationInstanceId = 4;
+    bool isSizeLimited = 5;
+}
+
+message TraceSegmentReference {
+    RefType refType = 1;
+    UniqueId parentTraceSegmentId = 2;
+    int32 parentSpanId = 3;
+    int32 parentApplicationInstanceId = 4;
+    string networkAddress = 5;
+    int32 networkAddressId = 6;
+    int32 entryApplicationInstanceId = 7;
+    string entryServiceName = 8;
+    int32 entryServiceId = 9;
+    string parentServiceName = 10;
+    int32 parentServiceId = 11;
+}
+
+message SpanObject {
+    int32 spanId = 1;
+    int32 parentSpanId = 2;
+    int64 startTime = 3;
+    int64 endTime = 4;
+    repeated TraceSegmentReference refs = 5;
+    int32 operationNameId = 6;
+    string operationName = 7;
+    int32 peerId = 8;
+    string peer = 9;
+    SpanType spanType = 10;
+    SpanLayer spanLayer = 11;
+    int32 componentId = 12;
+    string component = 13;
+    bool isError = 14;
+    repeated KeyWithStringValue tags = 15;
+    repeated LogMessage logs = 16;
+}
+
+enum RefType {
+    CrossProcess = 0;
+    CrossThread = 1;
+}
+
+enum SpanLayer {
+    Unknown = 0;
+    Database = 1;
+    RPCFramework = 2;
+    Http = 3;
+    MQ = 4;
+    Cache = 5;
+}
+
+message LogMessage {
+    int64 time = 1;
+    repeated KeyWithStringValue data = 2;
+}