// Copyright 2023 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
//
// http://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.api;
import "google/protobuf/descriptor.proto";
option go_package = "google.golang.org/genproto/googleapis/api/annotations;annotations";
option java_multiple_files = true;
option java_outer_classname = "RoutingProto";
option java_package = "com.google.api";
option objc_class_prefix = "GAPI";
extend google.protobuf.MethodOptions {
// See RoutingRule.
google.api.RoutingRule routing = 72295729;
}
// Specifies the routing information that should be sent along with the request
// in the form of routing header.
// **NOTE:** All service configuration rules follow the "last one wins" order.
//
// The examples below will apply to an RPC which has the following request type:
//
// Message Definition:
//
// message Request {
// // The name of the Table
// // Values can be of the following formats:
// // - `projects/<project>/tables/<table>`
// // - `projects/<project>/instances/<instance>/tables/<table>`
// // - `region/<region>/zones/<zone>/tables/<table>`
// string table_name = 1;
//
// // This value specifies routing for replication.
// // It can be in the following formats:
// // - `profiles/<profile_id>`
// // - a legacy `profile_id` that can be any string
// string app_profile_id = 2;
// }
//
// Example message:
//
// {
// table_name: projects/proj_foo/instances/instance_bar/table/table_baz,
// app_profile_id: profiles/prof_qux
// }
//
// The routing header consists of one or multiple key-value pairs. Every key
// and value must be percent-encoded, and joined together in the format of
// `key1=value1&key2=value2`.
// In the examples below I am skipping the percent-encoding for readablity.
//
// Example 1
//
// Extracting a field from the request to put into the routing header
// unchanged, with the key equal to the field name.
//
// annotation:
//
// option (google.api.routing) = {
// // Take the `app_profile_id`.
// routing_parameters {
// field: "app_profile_id"
// }
// };
//
// result:
//
// x-goog-request-params: app_profile_id=profiles/prof_qux
//
// Example 2
//
// Extracting a field from the request to put into the routing header
// unchanged, with the key different from the field name.
//
// annotation:
//
// option (google.api.routing) = {
// // Take the `app_profile_id`, but name it `routing_id` in the header.
// routing_parameters {
// field: "app_profile_id"
// path_template: "{routing_id=**}"
// }
// };
//
// result:
//
// x-goog-request-params: routing_id=profiles/prof_qux
//
// Example 3
//
// Extracting a field from the request to put into the routing
// header, while matching a path template syntax on the field's value.
//
// NB: it is more useful to send nothing than to send garbage for the purpose
// of dynamic routing, since garbage pollutes cache. Thus the matching.
//
// Sub-example 3a
//
// The field matches the template.
//
// annotation:
//
// option (google.api.routing) = {
// // Take the `table_name`, if it's well-formed (with project-based
// // syntax).
// routing_parameters {
// field: "table_name"
// path_template: "{table_name=projects/*/instances/*/**}"
// }
// };
//
// result:
//
// x-goog-request-params:
// table_name=projects/proj_foo/instances/instance_bar/table/table_baz
//
// Sub-example 3b
//
// The field does not match the template.
//
// annotation:
//
// option (google.api.routing) = {
// // Take the `table_name`, if it's well-formed (with region-based
// // syntax).
// routing_parameters {
// field: "table_name"
// path_template: "{table_name=regions/*/zones/*/**}"
// }
// };
//
// result:
//
// <no routing header will be sent>
//
// Sub-example 3c
//
// Multiple alternative conflictingly named path templates are
// specified. The one that matches is used to construct the header.
//
// annotation:
//
// option (google.api.routing) = {
// // Take the `table_name`, if it's well-formed, whether
// // using the region- or projects-based syntax.
//
// routing_parameters {
// field: "table_name"
// path_template: "{table_name=regions/*/zones/*/**}"
// }
// routing_parameters {
// field: "table_name"
// path_template: "{table_name=projects/*/instances/*/**}"
// }
// };
//
// result:
//
// x-goog-request-params:
// table_name=projects/proj_foo/instances/instance_bar/table/table_baz
//
// Example 4
//
// Extracting a single routing header key-value pair by matching a
// template syntax on (a part of) a single request field.
//
// annotation:
//
// option (google.api.routing) = {
// // Take just the project id from the `table_name` field.
// routing_parameters {
// field: "table_name"
// path_template: "{routing_id=projects/*}/**"
// }
// };
//
// result:
//
// x-goog-request-params: routing_id=projects/proj_foo
//
// Example 5
//
// Extracting a single routing header key-value pair by matching
// several conflictingly named path templates on (parts of) a single request
// field. The last template to match "wins" the conflict.
//
// annotation:
//
// option (google.api.routing) = {
// // If the `table_name` does not have instances information,
// // take just the project id for routing.
// // Otherwise take project + instance.
//
// routing_parameters {
// field: "table_name"
// path_template: "{routing_id=projects/*}/**"
// }
// routing_parameters {
// field: "table_name"
// path_template: "{routing_id=projects/*/instances/*}/**"
// }
// };
//
// result:
//
// x-goog-request-params:
// routing_id=projects/proj_foo/instances/instance_bar
//
// Example 6
//
// Extracting multiple routing header key-value pairs by matching
// several non-conflicting path templates on (parts of) a single request field.
//
// Sub-example 6a
//
// Make the templates strict, so that if the `table_name` does not
// have an instance information, nothing is sent.
//
// annotation:
//
// option (google.api.routing) = {
// // The routing code needs two keys instead of one composite
// // but works only for the tables with the "project-instance" name
// // syntax.
//
// routing_parameters {
// field: "table_name"
// path_template: "{project_id=projects/*}/instances/*/**"
// }
// routing_parameters {
// field: "table_name"
// path_template: "projects/*/{instance_id=instances/*}/**"
// }
// };
//
// result:
//
// x-goog-request-params:
// project_id=projects/proj_foo&instance_id=instances/instance_bar
//
// Sub-example 6b
//
// Make the templates loose, so that if the `table_name` does not
// have an instance information, just the project id part is sent.
//
// annotation:
//
// option (google.api.routing) = {
// // The routing code wants two keys instead of one composite
// // but will work with just the `project_id` for tables without
// // an instance in the `table_name`.
//
// routing_parameters {
// field: "table_name"
// path_template: "{project_id=projects/*}/**"
// }
// routing_parameters {
// field: "table_name"
// path_template: "projects/*/{instance_id=instances/*}/**"
// }
// };
//
// result (is the same as 6a for our example message because it has the instance
// information):
//
// x-goog-request-params:
// project_id=projects/proj_foo&instance_id=instances/instance_bar
//
// Example 7
//
// Extracting multiple routing header key-value pairs by matching
// several path templates on multiple request fields.
//
// NB: note that here there is no way to specify sending nothing if one of the
// fields does not match its template. E.g. if the `table_name` is in the wrong
// format, the `project_id` will not be sent, but the `routing_id` will be.
// The backend routing code has to be aware of that and be prepared to not
// receive a full complement of keys if it expects multiple.
//
// annotation:
//
// option (google.api.routing) = {
// // The routing needs both `project_id` and `routing_id`
// // (from the `app_profile_id` field) for routing.
//
// routing_parameters {
// field: "table_name"
// path_template: "{project_id=projects/*}/**"
// }
// routing_parameters {
// field: "app_profile_id"
// path_template: "{routing_id=**}"
// }
// };
//
// result:
//
// x-goog-request-params:
// project_id=projects/proj_foo&routing_id=profiles/prof_qux
//
// Example 8
//
// Extracting a single routing header key-value pair by matching
// several conflictingly named path templates on several request fields. The
// last template to match "wins" the conflict.
//
// annotation:
//
// option (google.api.routing) = {
// // The `routing_id` can be a project id or a region id depending on
// // the table name format, but only if the `app_profile_id` is not set.
// // If `app_profile_id` is set it should be used instead.
//
// routing_parameters {
// field: "table_name"
// path_template: "{routing_id=projects/*}/**"
// }
// routing_parameters {
// field: "table_name"
// path_template: "{routing_id=regions/*}/**"
// }
// routing_parameters {
// field: "app_profile_id"
// path_template: "{routing_id=**}"
// }
// };
//
// result:
//
// x-goog-request-params: routing_id=profiles/prof_qux
//
// Example 9
//
// Bringing it all together.
//
// annotation:
//
// option (google.api.routing) = {
// // For routing both `table_location` and a `routing_id` are needed.
// //
// // table_location can be either an instance id or a region+zone id.
// //
// // For `routing_id`, take the value of `app_profile_id`
// // - If it's in the format `profiles/<profile_id>`, send
// // just the `<profile_id>` part.
// // - If it's any other literal, send it as is.
// // If the `app_profile_id` is empty, and the `table_name` starts with
// // the project_id, send that instead.
//
// routing_parameters {
// field: "table_name"
// path_template: "projects/*/{table_location=instances/*}/tables/*"
// }
// routing_parameters {
// field: "table_name"
// path_template: "{table_location=regions/*/zones/*}/tables/*"
// }
// routing_parameters {
// field: "table_name"
// path_template: "{routing_id=projects/*}/**"
// }
// routing_parameters {
// field: "app_profile_id"
// path_template: "{routing_id=**}"
// }
// routing_parameters {
// field: "app_profile_id"
// path_template: "profiles/{routing_id=*}"
// }
// };
//
// result:
//
// x-goog-request-params:
// table_location=instances/instance_bar&routing_id=prof_qux
message RoutingRule {
// A collection of Routing Parameter specifications.
// **NOTE:** If multiple Routing Parameters describe the same key
// (via the `path_template` field or via the `field` field when
// `path_template` is not provided), "last one wins" rule
// determines which Parameter gets used.
// See the examples for more details.
repeated RoutingParameter routing_parameters = 2;
}
// A projection from an input message to the GRPC or REST header.
message RoutingParameter {
// A request field to extract the header key-value pair from.
string field = 1;
// A pattern matching the key-value field. Optional.
// If not specified, the whole field specified in the `field` field will be
// taken as value, and its name used as key. If specified, it MUST contain
// exactly one named segment (along with any number of unnamed segments) The
// pattern will be matched over the field specified in the `field` field, then
// if the match is successful:
// - the name of the single named segment will be used as a header name,
// - the match value of the segment will be used as a header value;
// if the match is NOT successful, nothing will be sent.
//
// Example:
//
// -- This is a field in the request message
// | that the header value will be extracted from.
// |
// | -- This is the key name in the
// | | routing header.
// V |
// field: "table_name" v
// path_template: "projects/*/{table_location=instances/*}/tables/*"
// ^ ^
// | |
// In the {} brackets is the pattern that -- |
// specifies what to extract from the |
// field as a value to be sent. |
// |
// The string in the field must match the whole pattern --
// before brackets, inside brackets, after brackets.
//
// When looking at this specific example, we can see that:
// - A key-value pair with the key `table_location`
// and the value matching `instances/*` should be added
// to the x-goog-request-params routing header.
// - The value is extracted from the request message's `table_name` field
// if it matches the full pattern specified:
// `projects/*/instances/*/tables/*`.
//
// **NB:** If the `path_template` field is not provided, the key name is
// equal to the field name, and the whole field should be sent as a value.
// This makes the pattern for the field and the value functionally equivalent
// to `**`, and the configuration
//
// {
// field: "table_name"
// }
//
// is a functionally equivalent shorthand to:
//
// {
// field: "table_name"
// path_template: "{table_name=**}"
// }
//
// See Example 1 for more details.
string path_template = 2;
}