Class RoutingRule (2.72.0)

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. The order of the key-value pairs is undefined, the order of the routing_parameters in the RoutingRule only matters for the evaluation order of the path templates when field is the same. See the examples below for more details.

Every key and value in the routing header must be percent-encoded, and joined together in the following format: key1=value1&key2=value2. The examples below skip the percent-encoding for readability.

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

Protobuf type google.api.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 .google.api.RoutingParameter routing_parameters = 2;

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 .google.api.RoutingParameter routing_parameters = 2;

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 .google.api.RoutingParameter routing_parameters = 2;

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 .google.api.RoutingParameter routing_parameters = 2;

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 .google.api.RoutingParameter routing_parameters = 2;