def add_auth()

in botocore/crt/auth.py [0:0]
41 lines of code
6 McCabe index (conditional complexity)

    def add_auth(self, request):
        if self.credentials is None:
            raise NoCredentialsError()

        # Use utcnow() because that's what gets mocked by tests, but set
        # timezone because CRT assumes naive datetime is local time.
        datetime_now = datetime.datetime.utcnow().replace(
            tzinfo=datetime.timezone.utc)

        # Use existing 'X-Amz-Content-SHA256' header if able
        existing_sha256 = self._get_existing_sha256(request)

        self._modify_request_before_signing(request)

        credentials_provider = awscrt.auth.AwsCredentialsProvider.new_static(
            access_key_id=self.credentials.access_key,
            secret_access_key=self.credentials.secret_key,
            session_token=self.credentials.token)

        if self._should_sha256_sign_payload(request):
            if existing_sha256:
                explicit_payload = existing_sha256
            else:
                explicit_payload = None  # to be calculated during signing
        else:
            explicit_payload = UNSIGNED_PAYLOAD

        if self._should_add_content_sha256_header(explicit_payload):
            body_header = \
                awscrt.auth.AwsSignedBodyHeaderType.X_AMZ_CONTENT_SHA_256
        else:
            body_header = awscrt.auth.AwsSignedBodyHeaderType.NONE

        signing_config = awscrt.auth.AwsSigningConfig(
            algorithm=awscrt.auth.AwsSigningAlgorithm.V4,
            signature_type=self._SIGNATURE_TYPE,
            credentials_provider=credentials_provider,
            region=self._region_name,
            service=self._service_name,
            date=datetime_now,
            should_sign_header=self._should_sign_header,
            use_double_uri_encode=self._USE_DOUBLE_URI_ENCODE,
            should_normalize_uri_path=self._SHOULD_NORMALIZE_URI_PATH,
            signed_body_value=explicit_payload,
            signed_body_header_type=body_header,
            expiration_in_seconds=self._expiration_in_seconds,
        )
        crt_request = self._crt_request_from_aws_request(request)
        future = awscrt.auth.aws_sign_request(crt_request, signing_config)
        future.result()
        self._apply_signing_changes(request, crt_request)