data.proto

// Copyright 2025 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

syntax = "proto3";

package google.events.cloud.eventarc.v1;

import "google/protobuf/duration.proto";
import "google/protobuf/timestamp.proto";
import "google/rpc/code.proto";

option csharp_namespace = "Google.Events.Protobuf.Cloud.Eventarc.V1";
option php_namespace = "Google\\Events\\Cloud\\Eventarc\\V1";
option ruby_package = "Google::Events::Cloud::Eventarc::V1";

// A representation of the Channel resource.
// A Channel is a resource on which event providers publish their events.
// The published events are delivered through the transport associated with the
// channel. Note that a channel is associated with exactly one event provider.
message Channel {
  // State lists all the possible states of a Channel
  enum State {
    // Default value. This value is unused.
    STATE_UNSPECIFIED = 0;

    // The PENDING state indicates that a Channel has been created successfully
    // and there is a new activation token available for the subscriber to use
    // to convey the Channel to the provider in order to create a Connection.
    PENDING = 1;

    // The ACTIVE state indicates that a Channel has been successfully
    // connected with the event provider.
    // An ACTIVE Channel is ready to receive and route events from the
    // event provider.
    ACTIVE = 2;

    // The INACTIVE state indicates that the Channel cannot receive events
    // permanently. There are two possible cases this state can happen:
    //
    // 1. The SaaS provider disconnected from this Channel.
    // 2. The Channel activation token has expired but the SaaS provider
    //    wasn't connected.
    //
    // To re-establish a Connection with a provider, the subscriber
    // should create a new Channel and give it to the provider.
    INACTIVE = 3;
  }

  // Required. The resource name of the channel. Must be unique within the
  // location on the project and must be in
  // `projects/{project}/locations/{location}/channels/{channel_id}` format.
  string name = 1;

  // Output only. Server assigned unique identifier for the channel. The value
  // is a UUID4 string and guaranteed to remain unchanged until the resource is
  // deleted.
  string uid = 2;

  // Output only. The creation time.
  google.protobuf.Timestamp create_time = 5;

  // Output only. The last-modified time.
  google.protobuf.Timestamp update_time = 6;

  // The name of the event provider (e.g. Eventarc SaaS partner) associated
  // with the channel. This provider will be granted permissions to publish
  // events to the channel. Format:
  // `projects/{project}/locations/{location}/providers/{provider_id}`.
  string provider = 7;

  oneof transport {
    // Output only. The name of the Pub/Sub topic created and managed by
    // Eventarc system as a transport for the event delivery. Format:
    // `projects/{project}/topics/{topic_id}`.
    string pubsub_topic = 8;
  }

  // Output only. The state of a Channel.
  State state = 9;

  // Output only. The activation token for the channel. The token must be used
  // by the provider to register the channel for publishing.
  string activation_token = 10;

  // Optional. Resource name of a KMS crypto key (managed by the user) used to
  // encrypt/decrypt their event data.
  //
  // It must match the pattern
  // `projects/*/locations/*/keyRings/*/cryptoKeys/*`.
  string crypto_key_name = 11;

  // Output only. Whether or not this Channel satisfies the requirements of
  // physical zone separation
  bool satisfies_pzs = 12;

  // Optional. Resource labels.
  map<string, string> labels = 13;
}

// A representation of the ChannelConnection resource.
// A ChannelConnection is a resource which event providers create during the
// activation process to establish a connection between the provider and the
// subscriber channel.
message ChannelConnection {
  // Required. The name of the connection.
  string name = 1;

  // Output only. Server assigned ID of the resource.
  // The server guarantees uniqueness and immutability until deleted.
  string uid = 2;

  // Required. The name of the connected subscriber Channel.
  // This is a weak reference to avoid cross project and cross accounts
  // references. This must be in
  // `projects/{project}/location/{location}/channels/{channel_id}` format.
  string channel = 5;

  // Output only. The creation time.
  google.protobuf.Timestamp create_time = 6;

  // Output only. The last-modified time.
  google.protobuf.Timestamp update_time = 7;

  // Optional. Resource labels.
  map<string, string> labels = 9;
}

// An enrollment represents a subscription for messages on a particular message
// bus. It defines a matching criteria for messages on the bus and the
// subscriber endpoint where matched messages should be delivered.
message Enrollment {
  // Identifier. Resource name of the form
  // projects/{project}/locations/{location}/enrollments/{enrollment}
  string name = 1;

  // Output only. Server assigned unique identifier for the channel. The value
  // is a UUID4 string and guaranteed to remain unchanged until the resource is
  // deleted.
  string uid = 2;

  // Output only. This checksum is computed by the server based on the value of
  // other fields, and might be sent only on update and delete requests to
  // ensure that the client has an up-to-date value before proceeding.
  string etag = 3;

  // Output only. The creation time.
  google.protobuf.Timestamp create_time = 4;

  // Output only. The last-modified time.
  google.protobuf.Timestamp update_time = 5;

  // Optional. Resource labels.
  map<string, string> labels = 6;

  // Optional. Resource annotations.
  map<string, string> annotations = 7;

  // Optional. Resource display name.
  string display_name = 8;

  // Required. A CEL expression identifying which messages this enrollment
  // applies to.
  string cel_match = 9;

  // Required. Immutable. Resource name of the message bus identifying the
  // source of the messages. It matches the form
  // projects/{project}/locations/{location}/messageBuses/{messageBus}.
  string message_bus = 10;

  // Required. Destination is the Pipeline that the Enrollment is delivering to.
  // It must point to the full resource name of a Pipeline. Format:
  // "projects/{PROJECT_ID}/locations/{region}/pipelines/{PIPELINE_ID)"
  string destination = 11;
}

// The configuration for Platform Telemetry logging for Eventarc Advanced
// resources.
message LoggingConfig {
  // The different severities for logging supported by Eventarc Advanced
  // resources.
  // This enum is an exhaustive list of log severities and is FROZEN. Do not
  // expect new values to be added.
  enum LogSeverity {
    // Log severity is not specified. This value is treated the same as NONE,
    // but is used to distinguish between no update and update to NONE in
    // update_masks.
    LOG_SEVERITY_UNSPECIFIED = 0;

    // Default value at resource creation, presence of this value must be
    // treated as no logging/disable logging.
    NONE = 1;

    // Debug or trace level logging.
    DEBUG = 2;

    // Routine information, such as ongoing status or performance.
    INFO = 3;

    // Normal but significant events, such as start up, shut down, or a
    // configuration change.
    NOTICE = 4;

    // Warning events might cause problems.
    WARNING = 5;

    // Error events are likely to cause problems.
    ERROR = 6;

    // Critical events cause more severe problems or outages.
    CRITICAL = 7;

    // A person must take action immediately.
    ALERT = 8;

    // One or more systems are unusable.
    EMERGENCY = 9;
  }

  // Optional. The minimum severity of logs that will be sent to
  // Stackdriver/Platform Telemetry. Logs at severitiy ≥ this value will be
  // sent, unless it is NONE.
  LogSeverity log_severity = 1;
}

// A GoogleApiSource represents a subscription of 1P events from a MessageBus.
message GoogleApiSource {
  // Config to enable subscribing to all events from a list of projects.
  message ProjectSubscriptions {
    // Required. A list of projects to receive events from.
    //
    // All the projects must be in the same org. The listed projects should have
    // the format project/{identifier} where identifier can be either the
    // project id for project number. A single list may contain both formats. At
    // most 100 projects can be listed.
    repeated string list = 1;
  }

  // Config to enabled subscribing to events from other projects in the org.
  message OrganizationSubscription {
    // Required. Enable org level subscription.
    bool enabled = 1;
  }

  // Identifier. Resource name of the form
  // projects/{project}/locations/{location}/googleApiSources/{google_api_source}
  string name = 1;

  // Output only. Server assigned unique identifier for the channel. The value
  // is a UUID4 string and guaranteed to remain unchanged until the resource is
  // deleted.
  string uid = 2;

  // Output only. This checksum is computed by the server based on the value of
  // other fields, and might be sent only on update and delete requests to
  // ensure that the client has an up-to-date value before proceeding.
  string etag = 3;

  // Output only. The creation time.
  google.protobuf.Timestamp create_time = 4;

  // Output only. The last-modified time.
  google.protobuf.Timestamp update_time = 5;

  // Optional. Resource labels.
  map<string, string> labels = 6;

  // Optional. Resource annotations.
  map<string, string> annotations = 7;

  // Optional. Resource display name.
  string display_name = 8;

  // Required. Destination is the message bus that the GoogleApiSource is
  // delivering to. It must be point to the full resource name of a MessageBus.
  // Format:
  // "projects/{PROJECT_ID}/locations/{region}/messagesBuses/{MESSAGE_BUS_ID)
  string destination = 9;

  // Optional. Resource name of a KMS crypto key (managed by the user) used to
  // encrypt/decrypt their event data.
  //
  // It must match the pattern
  // `projects/*/locations/*/keyRings/*/cryptoKeys/*`.
  string crypto_key_name = 10;

  // Optional. Config to control Platform logging for the GoogleApiSource.
  LoggingConfig logging_config = 11;

  // Config to enabled subscribing to events from other projects in the org.
  //
  // Users need the eventarc.googleApiSource.create permission on the entire org
  // in order to create a resource with these settings.
  oneof wide_scope_subscription {
    // Optional. Config to enable subscribing to events from all projects in the
    // GoogleApiSource's org.
    OrganizationSubscription organization_subscription = 12;

    // Optional. Config to enable subscribing to all events from a list of
    // projects.
    //
    // All the projects must be in the same org as the GoogleApiSource.
    ProjectSubscriptions project_subscriptions = 13;
  }
}

// Network Configuration that can be inherited by other protos.
message NetworkConfig {
  // Required. Name of the NetworkAttachment that allows access to the
  // customer's VPC. Format:
  // `projects/{PROJECT_ID}/regions/{REGION}/networkAttachments/{NETWORK_ATTACHMENT_NAME}`
  string network_attachment = 1;
}

// MessageBus for the messages flowing through the system. The admin has
// visibility and control over the messages being published and consumed and can
// restrict publishers and subscribers to only a subset of data available in the
// system by defining authorization policies.
message MessageBus {
  // Identifier. Resource name of the form
  // projects/{project}/locations/{location}/messageBuses/{message_bus}
  string name = 1;

  // Output only. Server assigned unique identifier for the channel. The value
  // is a UUID4 string and guaranteed to remain unchanged until the resource is
  // deleted.
  string uid = 2;

  // Output only. This checksum is computed by the server based on the value of
  // other fields, and might be sent only on update and delete requests to
  // ensure that the client has an up-to-date value before proceeding.
  string etag = 3;

  // Output only. The creation time.
  google.protobuf.Timestamp create_time = 4;

  // Output only. The last-modified time.
  google.protobuf.Timestamp update_time = 5;

  // Optional. Resource labels.
  map<string, string> labels = 6;

  // Optional. Resource annotations.
  map<string, string> annotations = 7;

  // Optional. Resource display name.
  string display_name = 8;

  // Optional. Resource name of a KMS crypto key (managed by the user) used to
  // encrypt/decrypt their event data.
  //
  // It must match the pattern
  // `projects/*/locations/*/keyRings/*/cryptoKeys/*`.
  string crypto_key_name = 10;

  // Optional. Config to control Platform logging for the Message Bus. This log
  // configuration is applied to the Message Bus itself, and all the Enrollments
  // attached to it.
  LoggingConfig logging_config = 11;
}

// A representation of the Pipeline resource.
message Pipeline {
  // Represents the format of message data.
  message MessagePayloadFormat {
    // The format of a JSON message payload.
    message JsonFormat {}

    // The format of a Protobuf message payload.
    message ProtobufFormat {
      // Optional. The entire schema definition is stored in this field.
      string schema_definition = 1;
    }

    // The format of an AVRO message payload.
    message AvroFormat {
      // Optional. The entire schema definition is stored in this field.
      string schema_definition = 1;
    }

    // The kind of message format.
    // One of Protobuf, Avro, and JSON supported.
    // This allows specification of what specific format
    // messages are sent and received.
    oneof kind {
      // Optional. Protobuf format.
      ProtobufFormat protobuf = 1;

      // Optional. Avro format.
      AvroFormat avro = 2;

      // Optional. JSON format.
      JsonFormat json = 3;
    }
  }

  // Represents a target of an invocation over HTTP.
  message Destination {
    // Represents a network config to be used for destination resolution and
    // connectivity.
    message NetworkConfig {
      // Required. Name of the NetworkAttachment that allows access to the
      // consumer VPC. Format:
      // `projects/{PROJECT_ID}/regions/{REGION}/networkAttachments/{NETWORK_ATTACHMENT_NAME}`
      string network_attachment = 1;
    }

    // Represents a HTTP endpoint destination.
    message HttpEndpoint {
      // Required. The URI of the HTTP endpoint.
      //
      // The value must be a RFC2396 URI string.
      // Examples: `https://svc.us-central1.p.local:8080/route`.
      // Only the HTTPS protocol is supported.
      string uri = 1;

      // Optional. The CEL expression used to modify how the destination-bound
      // HTTP request is constructed.
      //
      // If a binding expression is not specified here, the message
      // is treated as a CloudEvent and is mapped to the HTTP request according
      // to the CloudEvent HTTP Protocol Binding Binary Content Mode
      // (https://github.com/cloudevents/spec/blob/main/cloudevents/bindings/http-protocol-binding.md#31-binary-content-mode).
      // In this representation, all fields except the `data` and
      // `datacontenttype` field on the message are mapped to HTTP request
      // headers with a prefix of `ce-`.
      //
      // To construct the HTTP request payload and the value of the content-type
      // HTTP header, the payload format is defined as follows:
      // 1) Use the output_payload_format_type on the Pipeline.Destination if it
      //    is set, else:
      // 2) Use the input_payload_format_type on the Pipeline if it is set,
      //    else:
      // 3) Treat the payload as opaque binary data.
      //
      // The `data` field of the message is converted to the payload format or
      // left as-is for case 3) and then attached as the payload of the HTTP
      // request. The `content-type` header on the HTTP request is set to the
      // payload format type or left empty for case 3). However, if a mediation
      // has updated the `datacontenttype` field on the message so that it is
      // not the same as the payload format type but it is still a prefix of the
      // payload format type, then the `content-type` header on the HTTP request
      // is set to this `datacontenttype` value. For example, if the
      // `datacontenttype` is "application/json" and the payload format type is
      // "application/json; charset=utf-8", then the `content-type` header on
      // the HTTP request is set to "application/json; charset=utf-8".
      //
      // If a non-empty binding expression is specified then this expression is
      // used to modify the default CloudEvent HTTP Protocol Binding Binary
      // Content representation.
      // The result of the CEL expression must be a map of key/value pairs
      // which is used as follows:
      // - If a map named `headers` exists on the result of the expression,
      // then its key/value pairs are directly mapped to the HTTP request
      // headers. The headers values are constructed from the corresponding
      // value type's canonical representation. If the `headers` field doesn't
      // exist then the resulting HTTP request will be the headers of the
      // CloudEvent HTTP Binding Binary Content Mode representation of the final
      // message. Note: If the specified binding expression, has updated the
      // `datacontenttype` field on the message so that it is not the same as
      // the payload format type but it is still a prefix of the payload format
      // type, then the `content-type` header in the `headers` map is set to
      // this `datacontenttype` value.
      // - If a field named `body` exists on the result of the expression then
      // its value is directly mapped to the body of the request. If the value
      // of the `body` field is of type bytes or string then it is used for
      // the HTTP request body as-is, with no conversion. If the body field is
      // of any other type then it is converted to a JSON string. If the body
      // field does not exist then the resulting payload of the HTTP request
      // will be data value of the CloudEvent HTTP Binding Binary Content Mode
      // representation of the final message as described earlier.
      // - Any other fields in the resulting expression will be ignored.
      //
      // The CEL expression may access the incoming CloudEvent message in its
      // definition, as follows:
      // - The `data` field of the incoming CloudEvent message can be accessed
      // using the `message.data` value. Subfields of `message.data` may also be
      // accessed if an input_payload_format has been specified on the Pipeline.
      // - Each attribute of the incoming CloudEvent message can be accessed
      // using the `message.<key>` value, where <key> is replaced with the
      // name of the attribute.
      // - Existing headers can be accessed in the CEL expression using the
      // `headers` variable. The `headers` variable defines a map of key/value
      // pairs corresponding to the HTTP headers of the CloudEvent HTTP Binding
      // Binary Content Mode representation of the final message as described
      // earlier. For example, the following CEL expression can be used to
      // construct an HTTP request by adding an additional header to the HTTP
      // headers of the CloudEvent HTTP Binding Binary Content Mode
      // representation of the final message and by overwriting the body of the
      // request:
      //
      // ```
      // {
      //   "headers": headers.merge({"new-header-key": "new-header-value"}),
      //   "body": "new-body"
      // }
      // ```
      // - The default binding for the message payload can be accessed using the
      // `body` variable. It conatins a string representation of the message
      // payload in the format specified by the `output_payload_format` field.
      // If the `input_payload_format` field is not set, the `body`
      // variable contains the same message payload bytes that were published.
      //
      // Additionally, the following CEL extension functions are provided for
      // use in this CEL expression:
      // - toBase64Url:
      //   map.toBase64Url() -> string
      //     - Converts a CelValue to a base64url encoded string
      // - toJsonString: map.toJsonString() -> string
      //     - Converts a CelValue to a JSON string
      // - merge:
      //   map1.merge(map2) -> map3
      //     - Merges the passed CEL map with the existing CEL map the
      //     function is applied to.
      //     - If the same key exists in both maps, if the key's value is type
      //     map both maps are merged else the value from the passed map is
      //     used.
      // - denormalize:
      //   map.denormalize() -> map
      //     - Denormalizes a CEL map such that every value of type map or key
      //     in the map is expanded to return a single level map.
      //     - The resulting keys are "." separated indices of the map keys.
      //     - For example:
      //       {
      //         "a": 1,
      //         "b": {
      //           "c": 2,
      //           "d": 3
      //         }
      //         "e": [4, 5]
      //       }
      //       .denormalize()
      //       -> {
      //         "a": 1,
      //         "b.c": 2,
      //         "b.d": 3,
      //         "e.0": 4,
      //         "e.1": 5
      //       }
      // - setField:
      //   map.setField(key, value) -> message
      //     - Sets the field of the message with the given key to the
      //     given value.
      //     - If the field is not present it will be added.
      //     - If the field is present it will be overwritten.
      //     - The key can be a dot separated path to set a field in a nested
      //     message.
      //     - Key must be of type string.
      //     - Value may be any valid type.
      // - removeFields:
      //   map.removeFields([key1, key2, ...]) -> message
      //     - Removes the fields of the map with the given keys.
      //     - The keys can be a dot separated path to remove a field in a
      //     nested message.
      //     - If a key is not found it will be ignored.
      //     - Keys must be of type string.
      // - toMap:
      //   [map1, map2, ...].toMap() -> map
      //     - Converts a CEL list of CEL maps to a single CEL map
      // - toCloudEventJsonWithPayloadFormat:
      //   message.toCloudEventJsonWithPayloadFormat() -> map
      //     - Converts a message to the corresponding structure of JSON
      //     format for CloudEvents.
      //     - It converts `data` to destination payload format
      //     specified in `output_payload_format`. If `output_payload_format` is
      //     not set, the data will remain unchanged.
      //     - It also sets the corresponding datacontenttype of
      //     the CloudEvent, as indicated by
      //     `output_payload_format`. If no
      //     `output_payload_format` is set it will use the value of the
      //     "datacontenttype" attribute on the CloudEvent if present, else
      //     remove "datacontenttype" attribute.
      //     - This function expects that the content of the message will
      //     adhere to the standard CloudEvent format. If it doesn't then this
      //     function will fail.
      //     - The result is a CEL map that corresponds to the JSON
      //     representation of the CloudEvent. To convert that data to a JSON
      //     string it can be chained with the toJsonString function.
      //
      // The Pipeline expects that the message it receives adheres to the
      // standard CloudEvent format. If it doesn't then the outgoing message
      // request may fail with a persistent error.
      string message_binding_template = 3;
    }

    // Represents a config used to authenticate message requests.
    message AuthenticationConfig {
      // Represents a config used to authenticate with a Google OIDC token using
      // a Google Cloud service account. Use this authentication method to
      // invoke your Cloud Run and Cloud Functions destinations or HTTP
      // endpoints that support Google OIDC.
      message OidcToken {
        // Required. Service account email used to generate the OIDC Token.
        // The principal who calls this API must have
        // iam.serviceAccounts.actAs permission in the service account. See
        // https://cloud.google.com/iam/docs/understanding-service-accounts
        // for more information. Eventarc service agents must have
        // roles/roles/iam.serviceAccountTokenCreator role to allow the
        // Pipeline to create OpenID tokens for authenticated requests.
        string service_account = 1;

        // Optional. Audience to be used to generate the OIDC Token. The
        // audience claim identifies the recipient that the JWT is intended for.
        // If unspecified, the destination URI will be used.
        string audience = 2;
      }

      // Contains information needed for generating an
      // [OAuth token](https://developers.google.com/identity/protocols/OAuth2).
      // This type of authorization should generally only be used when calling
      // Google APIs hosted on *.googleapis.com.
      message OAuthToken {
        // Required. Service account email used to generate the [OAuth
        // token](https://developers.google.com/identity/protocols/OAuth2).
        // The principal who calls this API must have
        // iam.serviceAccounts.actAs permission in the service account. See
        // https://cloud.google.com/iam/docs/understanding-service-accounts
        // for more information. Eventarc service agents must have
        // roles/roles/iam.serviceAccountTokenCreator role to allow Pipeline
        // to create OAuth2 tokens for authenticated requests.
        string service_account = 1;

        // Optional. OAuth scope to be used for generating OAuth access token.
        // If not specified, "https://www.googleapis.com/auth/cloud-platform"
        // will be used.
        string scope = 2;
      }

      // The type of authentication method.
      oneof authentication_method_descriptor {
        // Optional. This authenticate method will apply Google OIDC tokens
        // signed by a Google Cloud service account to the requests.
        OidcToken google_oidc = 1;

        // Optional. If specified, an [OAuth
        // token](https://developers.google.com/identity/protocols/OAuth2) will
        // be generated and attached as an `Authorization` header in the HTTP
        // request.
        //
        // This type of authorization should generally only be used when calling
        // Google APIs hosted on *.googleapis.com.
        OAuthToken oauth_token = 2;
      }
    }

    // Optional. Network config is used to configure how Pipeline resolves and
    // connects to a destination.
    NetworkConfig network_config = 1;

    // The destination identifier to which the request should be routed to.
    oneof destination_descriptor {
      // Optional. An HTTP endpoint destination described by an URI.
      // If a DNS FQDN is provided as the endpoint, Pipeline will create a
      // peering zone to the consumer VPC and forward DNS requests to the VPC
      // specified by network config to resolve the service endpoint. See:
      // https://cloud.google.com/dns/docs/zones/zones-overview#peering_zones
      HttpEndpoint http_endpoint = 2;

      // Optional. The resource name of the Workflow whose Executions are
      // triggered by the events. The Workflow resource should be deployed in
      // the same project as the Pipeline. Format:
      // `projects/{project}/locations/{location}/workflows/{workflow}`
      string workflow = 3;

      // Optional. The resource name of the Message Bus to which events should
      // be published. The Message Bus resource should exist in the same project
      // as the Pipeline. Format:
      // `projects/{project}/locations/{location}/messageBuses/{message_bus}`
      string message_bus = 4;

      // Optional. The resource name of the Pub/Sub topic to which events should
      // be published. Format:
      // `projects/{project}/locations/{location}/topics/{topic}`
      string topic = 8;
    }

    // Optional. An authentication config used to authenticate message requests,
    // such that destinations can verify the source. For example, this can be
    // used with private Google Cloud destinations that require Google Cloud
    // credentials for access like Cloud Run. This field is optional and should
    // be set only by users interested in authenticated push.
    AuthenticationConfig authentication_config = 5;

    // Optional. The message format before it is delivered to the destination.
    // If not set, the message will be delivered in the format it was originally
    // delivered to the Pipeline. This field can only be set if
    // Pipeline.input_payload_format is also set.
    MessagePayloadFormat output_payload_format = 6;
  }

  // Mediation defines different ways to modify the Pipeline.
  message Mediation {
    // Transformation defines the way to transform an incoming message.
    message Transformation {
      // Optional. The CEL expression template to apply to transform messages.
      // The following CEL extension functions are provided for
      // use in this CEL expression:
      // - merge:
      //   map1.merge(map2) -> map3
      //     - Merges the passed CEL map with the existing CEL map the
      //     function is applied to.
      //     - If the same key exists in both maps, if the key's value is type
      //     map both maps are merged else the value from the passed map is
      //     used.
      // - denormalize:
      //   map.denormalize() -> map
      //     - Denormalizes a CEL map such that every value of type map or key
      //     in the map is expanded to return a single level map.
      //     - The resulting keys are "." separated indices of the map keys.
      //     - For example:
      //       {
      //         "a": 1,
      //         "b": {
      //           "c": 2,
      //           "d": 3
      //         }
      //         "e": [4, 5]
      //       }
      //       .denormalize()
      //       -> {
      //         "a": 1,
      //         "b.c": 2,
      //         "b.d": 3,
      //         "e.0": 4,
      //         "e.1": 5
      //       }
      // - setField:
      //   map.setField(key, value) -> message
      //     - Sets the field of the message with the given key to the
      //     given value.
      //     - If the field is not present it will be added.
      //     - If the field is present it will be overwritten.
      //     - The key can be a dot separated path to set a field in a nested
      //     message.
      //     - Key must be of type string.
      //     - Value may be any valid type.
      // - removeFields:
      //   map.removeFields([key1, key2, ...]) -> message
      //     - Removes the fields of the map with the given keys.
      //     - The keys can be a dot separated path to remove a field in a
      //     nested message.
      //     - If a key is not found it will be ignored.
      //     - Keys must be of type string.
      // - toMap:
      //   [map1, map2, ...].toMap() -> map
      //     - Converts a CEL list of CEL maps to a single CEL map
      // - toDestinationPayloadFormat():
      //   message.data.toDestinationPayloadFormat() -> string or bytes
      //     - Converts the message data to the destination payload format
      //     specified in Pipeline.Destination.output_payload_format
      //     - This function is meant to be applied to the message.data field.
      //     - If the destination payload format is not set, the function will
      //     return the message data unchanged.
      // - toCloudEventJsonWithPayloadFormat:
      //   message.toCloudEventJsonWithPayloadFormat() -> map
      //     - Converts a message to the corresponding structure of JSON
      //     format for CloudEvents
      //     - This function applies toDestinationPayloadFormat() to the
      //     message data. It also sets the corresponding datacontenttype of
      //     the CloudEvent, as indicated by
      //     Pipeline.Destination.output_payload_format. If no
      //     output_payload_format is set it will use the existing
      //     datacontenttype on the CloudEvent if present, else leave
      //     datacontenttype absent.
      //     - This function expects that the content of the message will
      //     adhere to the standard CloudEvent format. If it doesn't then this
      //     function will fail.
      //     - The result is a CEL map that corresponds to the JSON
      //     representation of the CloudEvent. To convert that data to a JSON
      //     string it can be chained with the toJsonString function.
      string transformation_template = 1;
    }

    // The config of mediation.
    oneof mediation_descriptor {
      // Optional. How the Pipeline is to transform messages
      Transformation transformation = 1;
    }
  }

  // The retry policy configuration for the Pipeline. The pipeline
  // exponentially backs off in case the destination is non responsive or
  // returns a retryable error code. The default semantics are as follows:
  // The backoff starts with a 5 second delay and doubles the
  // delay after each failed attempt (10 seconds, 20 seconds, 40 seconds, etc.).
  // The delay is capped at 60 seconds by default.
  // Please note that if you set the min_retry_delay and max_retry_delay fields
  // to the same value this will make the duration between retries constant.
  message RetryPolicy {
    // Optional. The maximum number of delivery attempts for any message. The
    // value must be between 1 and 100. The default value for this field is 5.
    int32 max_attempts = 1;

    // Optional. The minimum amount of seconds to wait between retry attempts.
    // The value must be between 1 and 600. The default value for this field
    // is 5.
    google.protobuf.Duration min_retry_delay = 2;

    // Optional. The maximum amount of seconds to wait between retry attempts.
    // The value must be between 1 and 600. The default value for this field
    // is 60.
    google.protobuf.Duration max_retry_delay = 3;
  }

  // Identifier. The resource name of the Pipeline. Must be unique within the
  // location of the project and must be in
  // `projects/{project}/locations/{location}/pipelines/{pipeline}` format.
  string name = 1;

  // Output only. The creation time.
  // A timestamp in RFC3339 UTC "Zulu" format, with nanosecond resolution and up
  // to nine fractional digits. Examples: "2014-10-02T15:01:23Z" and
  // "2014-10-02T15:01:23.045123456Z".
  google.protobuf.Timestamp create_time = 2;

  // Output only. The last-modified time.
  // A timestamp in RFC3339 UTC "Zulu" format, with nanosecond resolution and up
  // to nine fractional digits. Examples: "2014-10-02T15:01:23Z" and
  // "2014-10-02T15:01:23.045123456Z".
  google.protobuf.Timestamp update_time = 3;

  // Optional. User labels attached to the Pipeline that can be used to group
  // resources. An object containing a list of "key": value pairs. Example: {
  // "name": "wrench", "mass": "1.3kg", "count": "3" }.
  map<string, string> labels = 4;

  // Output only. Server-assigned unique identifier for the Pipeline. The value
  // is a UUID4 string and guaranteed to remain unchanged until the resource is
  // deleted.
  string uid = 5;

  // Optional. User-defined annotations. See
  // https://google.aip.dev/128#annotations.
  map<string, string> annotations = 6;

  // Optional. Display name of resource.
  string display_name = 7;

  // Required. List of destinations to which messages will be forwarded.
  // Currently, exactly one destination is supported per Pipeline.
  repeated Destination destinations = 8;

  // Optional. List of mediation operations to be performed on the message.
  // Currently, only one Transformation operation is allowed in each Pipeline.
  repeated Mediation mediations = 9;

  // Optional. Resource name of a KMS crypto key (managed by the user) used to
  // encrypt/decrypt the event data. If not set, an internal Google-owned key
  // will be used to encrypt messages. It must match the pattern
  // "projects/{project}/locations/{location}/keyRings/{keyring}/cryptoKeys/{key}".
  string crypto_key_name = 10;

  // Optional. The payload format expected for the messages received by the
  // Pipeline. If input_payload_format is set then any messages not matching
  // this format will be treated as persistent errors. If input_payload_format
  // is not set, then the message data will be treated as an opaque binary and
  // no output format can be set on the Pipeline through the
  // Pipeline.Destination.output_payload_format field. Any Mediations on the
  // Pipeline that involve access to the data field will fail as persistent
  // errors.
  MessagePayloadFormat input_payload_format = 11;

  // Optional. Config to control Platform Logging for Pipelines.
  LoggingConfig logging_config = 12;

  // Optional. The retry policy to use in the pipeline.
  RetryPolicy retry_policy = 13;

  // Output only. This checksum is computed by the server based on the value of
  // other fields, and might be sent only on create requests to ensure that the
  // client has an up-to-date value before proceeding.
  string etag = 99;

  // Output only. Whether or not this Pipeline satisfies the requirements of
  // physical zone separation
  bool satisfies_pzs = 14;
}

// A representation of the trigger resource.
message Trigger {
  // The retry policy configuration for the Trigger.
  //
  // Can only be set with Cloud Run destinations.
  message RetryPolicy {
    // Optional. The maximum number of delivery attempts for any message. The
    // only valid value is 1.
    int32 max_attempts = 1;
  }

  // Required. The resource name of the trigger. Must be unique within the
  // location of the project and must be in
  // `projects/{project}/locations/{location}/triggers/{trigger}` format.
  string name = 1;

  // Output only. Server-assigned unique identifier for the trigger. The value
  // is a UUID4 string and guaranteed to remain unchanged until the resource is
  // deleted.
  string uid = 2;

  // Output only. The creation time.
  google.protobuf.Timestamp create_time = 5;

  // Output only. The last-modified time.
  google.protobuf.Timestamp update_time = 6;

  // Required. Unordered list. The list of filters that applies to event
  // attributes. Only events that match all the provided filters are sent to the
  // destination.
  repeated EventFilter event_filters = 8;

  // Optional. The IAM service account email associated with the trigger. The
  // service account represents the identity of the trigger.
  //
  // The `iam.serviceAccounts.actAs` permission must be granted on the service
  // account to allow a principal to impersonate the service account. For more
  // information, see the
  // [Roles and permissions](/eventarc/docs/all-roles-permissions) page specific
  // to the trigger destination.
  string service_account = 9;

  // Required. Destination specifies where the events should be sent to.
  Destination destination = 10;

  // Optional. To deliver messages, Eventarc might use other Google Cloud
  // products as a transport intermediary. This field contains a reference to
  // that transport intermediary. This information can be used for debugging
  // purposes.
  Transport transport = 11;

  // Optional. User labels attached to the triggers that can be used to group
  // resources.
  map<string, string> labels = 12;

  // Optional. The name of the channel associated with the trigger in
  // `projects/{project}/locations/{location}/channels/{channel}` format.
  // You must provide a channel to receive events from Eventarc SaaS partners.
  string channel = 13;

  // Output only. The reason(s) why a trigger is in FAILED state.
  map<string, StateCondition> conditions = 15;

  // Optional. EventDataContentType specifies the type of payload in MIME
  // format that is expected from the CloudEvent data field. This is set to
  // `application/json` if the value is not defined.
  string event_data_content_type = 16;

  // Output only. Whether or not this Trigger satisfies the requirements of
  // physical zone separation
  bool satisfies_pzs = 19;

  // Optional. The retry policy to use in the Trigger.
  //
  // If unset, event delivery will be retried for up to 24 hours by default:
  // https://cloud.google.com/eventarc/docs/retry-events
  RetryPolicy retry_policy = 20;

  // Output only. This checksum is computed by the server based on the value of
  // other fields, and might be sent only on create requests to ensure that the
  // client has an up-to-date value before proceeding.
  string etag = 99;
}

// Filters events based on exact matches on the CloudEvents attributes.
message EventFilter {
  // Required. The name of a CloudEvents attribute. Currently, only a subset of
  // attributes are supported for filtering. You can [retrieve a specific
  // provider's supported event
  // types](/eventarc/docs/list-providers#describe-provider).
  //
  // All triggers MUST provide a filter for the 'type' attribute.
  string attribute = 1;

  // Required. The value for the attribute.
  string value = 2;

  // Optional. The operator used for matching the events with the value of the
  // filter. If not specified, only events that have an exact key-value pair
  // specified in the filter are matched. The allowed values are `path_pattern`
  // and `match-path-pattern`. `path_pattern` is only allowed for GCFv1
  // triggers.
  string operator = 3;
}

// A condition that is part of the trigger state computation.
message StateCondition {
  // The canonical code of the condition.
  google.rpc.Code code = 1;

  // Human-readable message.
  string message = 2;
}

// Represents a target of an invocation over HTTP.
message Destination {
  oneof descriptor {
    // Cloud Run fully-managed resource that receives the events. The resource
    // should be in the same project as the trigger.
    CloudRun cloud_run = 1;

    // The Cloud Function resource name. Cloud Functions V1 and V2 are
    // supported.
    // Format: `projects/{project}/locations/{location}/functions/{function}`
    //
    // This is a read-only field. Creating Cloud Functions V1/V2 triggers is
    // only supported via the Cloud Functions product. An error will be returned
    // if the user sets this value.
    string cloud_function = 2;

    // A GKE service capable of receiving events. The service should be running
    // in the same project as the trigger.
    GKE gke = 3;

    // The resource name of the Workflow whose Executions are triggered by
    // the events. The Workflow resource should be deployed in the same project
    // as the trigger.
    // Format: `projects/{project}/locations/{location}/workflows/{workflow}`
    string workflow = 4;

    // An HTTP endpoint destination described by an URI.
    HttpEndpoint http_endpoint = 5;
  }

  // Optional. Network config is used to configure how Eventarc resolves and
  // connect to a destination.
  // This should only be used with HttpEndpoint destination type.
  NetworkConfig network_config = 6;
}

// Represents the transport intermediaries created for the trigger to
// deliver events.
message Transport {
  oneof intermediary {
    // The Pub/Sub topic and subscription used by Eventarc as a transport
    // intermediary.
    Pubsub pubsub = 1;
  }
}

// Represents a Cloud Run destination.
message CloudRun {
  // Required. The name of the Cloud Run service being addressed. See
  // https://cloud.google.com/run/docs/reference/rest/v1/namespaces.services.
  //
  // Only services located in the same project as the trigger object
  // can be addressed.
  string service = 1;

  // Optional. The relative path on the Cloud Run service the events should be
  // sent to.
  //
  // The value must conform to the definition of a URI path segment (section 3.3
  // of RFC2396). Examples: "/route", "route", "route/subroute".
  string path = 2;

  // Required. The region the Cloud Run service is deployed in.
  string region = 3;
}

// Represents a GKE destination.
message GKE {
  // Required. The name of the cluster the GKE service is running in. The
  // cluster must be running in the same project as the trigger being created.
  string cluster = 1;

  // Required. The name of the Google Compute Engine in which the cluster
  // resides, which can either be compute zone (for example, us-central1-a) for
  // the zonal clusters or region (for example, us-central1) for regional
  // clusters.
  string location = 2;

  // Required. The namespace the GKE service is running in.
  string namespace = 3;

  // Required. Name of the GKE service.
  string service = 4;

  // Optional. The relative path on the GKE service the events should be sent
  // to.
  //
  // The value must conform to the definition of a URI path segment (section 3.3
  // of RFC2396). Examples: "/route", "route", "route/subroute".
  string path = 5;
}

// Represents a Pub/Sub transport.
message Pubsub {
  // Optional. The name of the Pub/Sub topic created and managed by Eventarc as
  // a transport for the event delivery. Format:
  // `projects/{PROJECT_ID}/topics/{TOPIC_NAME}`.
  //
  // You can set an existing topic for triggers of the type
  // `google.cloud.pubsub.topic.v1.messagePublished`. The topic you provide
  // here is not deleted by Eventarc at trigger deletion.
  string topic = 1;

  // Output only. The name of the Pub/Sub subscription created and managed by
  // Eventarc as a transport for the event delivery. Format:
  // `projects/{PROJECT_ID}/subscriptions/{SUBSCRIPTION_NAME}`.
  string subscription = 2;
}

// Represents a HTTP endpoint destination.
message HttpEndpoint {
  // Required. The URI of the HTTP endpoint.
  //
  // The value must be a RFC2396 URI string.
  // Examples: `http://10.10.10.8:80/route`,
  // `http://svc.us-central1.p.local:8080/`.
  // Only HTTP and HTTPS protocols are supported. The host can be either a
  // static IP addressable from the VPC specified by the network config, or
  // an internal DNS hostname of the service resolvable via Cloud DNS.
  string uri = 1;
}

// The data within all Trigger events.
message TriggerEventData {
  // The Trigger event payload.
  Trigger payload = 1;
}

// The data within all Channel events.
message ChannelEventData {
  // The Channel event payload.
  Channel payload = 1;
}

// The data within all ChannelConnection events.
message ChannelConnectionEventData {
  // The ChannelConnection event payload.
  ChannelConnection payload = 1;
}

// The data within all MessageBus events.
message MessageBusEventData {
  // The MessageBus event payload.
  MessageBus payload = 1;
}

// The data within all Enrollment events.
message EnrollmentEventData {
  // The Enrollment event payload.
  Enrollment payload = 1;
}

// The data within all Pipeline events.
message PipelineEventData {
  // The Pipeline event payload.
  Pipeline payload = 1;
}

// The data within all GoogleApiSource events.
message GoogleApiSourceEventData {
  // The GoogleApiSource event payload.
  GoogleApiSource payload = 1;
}