Well-known types

message Any {
  // Identifies the type of the serialized Protobuf message with a URI
  // reference consisting of a prefix ending in a slash and the
  // fully-qualified type name.
  //
  // Example: type.googleapis.com/google.protobuf.StringValue
  string type_url = 1;

  // Holds a Protobuf serialization of the type described by type_url.
  bytes value = 2;
}

import "google/protobuf/any.proto";

message ErrorDetail {
  string message = 1;
  google.protobuf.Any metadata = 2;
}

import (
    "google.golang.org/protobuf/types/known/anypb"
    mypb "example.com/myproto"
)

// Pack
detail := &mypb.ResourceInfo{Name: "projects/123"}
any, err := anypb.New(detail)

// Unpack
var info mypb.ResourceInfo
if err := any.UnmarshalTo(&info); err != nil {
    // type mismatch or decode error
}

message Timestamp {
  // Seconds of UTC time since Unix epoch 1970-01-01T00:00:00Z.
  // Must be between -62135596800 and 253402300799 inclusive.
  int64 seconds = 1;

  // Non-negative fractions of a second at nanosecond resolution.
  // Must be between 0 and 999,999,999 inclusive.
  int32 nanos = 2;
}

import "google/protobuf/timestamp.proto";

message Person {
  string name = 1;
  int32 id = 2;
  string email = 3;
  google.protobuf.Timestamp last_updated = 5;
}

message Duration {
  // Signed seconds of the span of time.
  // Must be from -315,576,000,000 to +315,576,000,000 inclusive.
  int64 seconds = 1;

  // Signed fractions of a second at nanosecond resolution.
  // For durations >= 1 second, nanos must have the same sign as seconds.
  // Must be from -999,999,999 to +999,999,999 inclusive.
  int32 nanos = 2;
}

// Pseudocode
Duration duration;
duration.seconds = end.seconds - start.seconds;
duration.nanos = end.nanos - start.nanos;

// Normalize if signs differ
if (duration.seconds < 0 && duration.nanos > 0) {
  duration.seconds += 1;
  duration.nanos -= 1000000000;
} else if (duration.seconds > 0 && duration.nanos < 0) {
  duration.seconds -= 1;
  duration.nanos += 1000000000;
}

// Represents a JSON object.
message Struct {
  // Unordered map of dynamically typed values.
  map<string, Value> fields = 1;
}

// Represents a JSON value.
message Value {
  oneof kind {
    NullValue null_value = 1;    // JSON null
    double number_value = 2;     // JSON number
    string string_value = 3;     // JSON string
    bool bool_value = 4;         // JSON boolean
    Struct struct_value = 5;     // JSON object
    ListValue list_value = 6;    // JSON array
  }
}

enum NullValue {
  NULL_VALUE = 0;
}

// Represents a JSON array.
message ListValue {
  repeated Value values = 1;
}

import "google/protobuf/struct.proto";

message ApiResponse {
  int32 status = 1;
  // Carry arbitrary JSON metadata without a typed schema
  google.protobuf.Struct metadata = 2;
}

// A generic empty message that you can re-use to avoid defining duplicated
// empty messages in your APIs.
message Empty {}

import "google/protobuf/empty.proto";

service Foo {
  rpc Bar(google.protobuf.Empty) returns (google.protobuf.Empty);
  rpc DeleteResource(DeleteResourceRequest) returns (google.protobuf.Empty);
}

// FieldMask represents a set of symbolic field paths, for example:
//     paths: "f.a"
//     paths: "f.b.d"
message FieldMask {
  repeated string paths = 1;
}

// In proto text format:
mask {
  paths: "user.display_name"
  paths: "photo"
}

// In JSON:
{ "mask": "user.displayName,photo" }

import "google/protobuf/field_mask.proto";

message UpdateUserRequest {
  User user = 1;
  // Only fields listed in update_mask will be modified.
  google.protobuf.FieldMask update_mask = 2;
}

// Wrapper message for `double`.
message DoubleValue  { double value = 1; }

// Wrapper message for `float`.
message FloatValue   { float value = 1; }

// Wrapper message for `int64`.
message Int64Value   { int64 value = 1; }

// Wrapper message for `uint64`.
message UInt64Value  { uint64 value = 1; }

// Wrapper message for `int32`.
message Int32Value   { int32 value = 1; }

// Wrapper message for `uint32`.
message UInt32Value  { uint32 value = 1; }

// Wrapper message for `bool`.
message BoolValue    { bool value = 1; }

// Wrapper message for `string`.
message StringValue  { string value = 1; }

// Wrapper message for `bytes`.
message BytesValue   { bytes value = 1; }

message Config {
  // Preferred in new APIs: optional scalar with explicit presence
  optional int32 timeout_seconds = 1;

  // Legacy pattern using wrapper type — avoid in new APIs
  google.protobuf.Int32Value legacy_timeout = 2;
}