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We recommend testing against real GCP APIs instead, or writing simple mocks for testing your use-case locally.

Cloud Operations API Mock

This project allows your tests to easily mock out Google Cloud Monitoring and Google Cloud Trace.

This is not an officially supported Google product.

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Apache header:

Copyright 2020 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.

Overview

Suppose you're trying to write integration tests for an exporter.

In the past, the exporter would have to point to an actual GCP instance.

Our mock server implements the same endpoints as the Cloud Trace and Cloud Monitoring APIs. This allows you to point the exporter to our mock server instead of calling actual GCP endpoints.

mock := cloudmock.NewCloudMock()
defer mock.Shutdown()
// Get the connection info of the mock.
clientOpt := []option.ClientOption{option.WithGRPCConn(mock.ClientConn())}

// Point the exporter to the mock server.
_, flush, err := traceExporter.InstallNewPipeline(
	[]traceExporter.Option{
		traceExporter.WithTraceClientOptions(clientOpt)
	}
)

Usage

All of the services can be used as a library, or as a stand-alone server

Library Mode

Install the project:

go get github.com/googleinterns/cloud-operations-api-mock

Import:

import "github.com/googleinterns/cloud-operations-api-mock/cloudmock"

Sample usage for Cloud Trace:

func TestXxx(t *testing.T) {
    // Start the mock server, defer the shutdown.
    mock := cloudmock.NewCloudMock()
    defer mock.Shutdown()
    // Set a delay of 20ms to simulate latency.
    mock.SetDelay(20 * time.Millisecond)

    // Omitted for brevity: create exporter, point to mock server and export a span.
    
    // Check that the correct number of spans was created.
    assert.EqualValues(t, 1, mock.GetNumSpans())
}

See the GoDocs for specific functions that cloudmock provides.

Stand-alone Server Mode

This mode allows the mock server to be used even if you aren't using Go. Simply start up the server and point the exporter to it.

Curl the binary:

curl -L https://github.com/googleinterns/cloud-operations-api-mock/releases/download/[version]/mock_server-x64-linux-[version]

Run the binary:

chmod +x mock_server-x64-linux-[version]
./mock_server-x64-linux-[version]

Optional flags:

-address=<host:port> runs the server on the given address. If this flag is not used, a default address of localhost:8080 is used
-summary outputs a static HTML file summary.html when the server shuts down, which contains a summary of the data received

Usage in Continuous Integration:

There are many ways to use the stand-alone server in continuous integration.

An example workflow would be having CircleCI curl the binary and put it somewhere (Ex. $PATH), and have the test spin up the server.

Here's a simplified example from the Python Cloud Trace exporter, after the CI curls the binary and adds it to $PATH.

class SampleIntegrationTest(unittest.TestCase):
    def setUp(self):
        # Start the mock server at some address.
        args = ["mock_server-x64-linux-[version]", "-address", self.address]
        self.mock_server_process = subprocess.Popen(
            args, stderr=subprocess.PIPE
        )

    def tearDown(self):
           # Kill the mock server.
        self.mock_server_process.kill()

    def test_xxx(self):
        # Create the trace exporter and point to the address of the mock server.
        channel = grpc.insecure_channel(self.address)
        transport = trace_service_grpc_transport.TraceServiceGrpcTransport(
            channel=channel
        )
        client = TraceServiceClient(transport=transport)
        trace_exporter = CloudTraceSpanExporter(self.project_id, client=client)

        # Omitted for brevity: Create spans, export them, make assertions.