Create methods: Method signature

This rule enforces that all Create standard methods have a google.api.method_signature annotation with an appropirate value, as mandated in AIP-133.

Details

This rule looks at any method beginning with Create, and complains if the google.api.method_signature annotation is missing, or if it is set to an incorrect value. Additional method signatures, if present, are ignored.

The correct value is "parent,{resource},{resource}_id" if the {resource}_id field exists, and "parent,{resource}" otherwise.

Examples

Incorrect code for this rule:

// Incorrect.
rpc CreateBook(CreateBookRequest) returns (Book) {
  // A google.api.method_signature annotation should be present.
}
// Incorrect.
rpc CreateBook(CreateBookRequest) returns (Book) {
  // Should be "parent,book" or "parent,book,book_id", depending on whether
  // a "book_id" field exists.
  option (google.api.method_signature) = "publisher,book";
}

Correct code for this rule:

If the book_id field does not exist:

// Correct.
rpc CreateBook(CreateBookRequest) returns (Book) {
  option (google.api.method_signature) = "parent,book";
}

If the book_id field exists:

// Correct.
rpc CreateBook(CreateBookRequest) returns (Book) {
  option (google.api.method_signature) = "parent,book,book_id";
}

Disabling

If you need to violate this rule, use a leading comment above the method. Remember to also include an aip.dev/not-precedent comment explaining why.

// (-- api-linter: core::0133::method-signature=disabled
//     aip.dev/not-precedent: We need to do this because reasons. --)
rpc CreateBook(CreateBookRequest) returns (Book) {
  option (google.api.method_signature) = "publisher,book";
}

If you need to violate this rule for an entire file, place the comment at the top of the file.