Coins Oracle

A lambda function which normalises many crypto currency APIs into a common interface. This allows you to query transactions and wallets using a singular API.

Development

Running Coins Oracle Locally requires:

once these are installed you can run go get ./... to install all of the required packages.

Adding A New Coin Client

In order to simplify local development coins-oracle comes with a new client generator. To use is run the following command with your given coin name and asset id e.g. Bitcoin & BTC.

$ go run ./cmd/coingen/main.go -name=<coin_name> -asset_id=<coin_symbol>

After running this command the coingen binary will generate corresponding client_<coin_name>.go and client_<coin_name>_test.go files under internal/transport. The client client file comes with some boilerplate code added and the test file has some pre-written assertions that you'll need to configure and implement to get passing.

The command also generates some fixture files for the tests under internal/test/fixture/<coin_name>, you should fill these in with the expected json responses from your mock coin server for your tests.

Testing

Tests are written with ginkgo and use gomega for assertions. All test files must be placed under the _test namespace and whitebox testing is to be avoided.

Each coin has test file associated with it. These tests are integration tests and use a mock server to generate JSON responses for each coin. This functionality is provided by the pkg/test package. The Server allows you to easily mock expected calls like such:

package client_test

import (
    "net/http"
    "testing"

    "github.com/hugorut/coins-oracle/pkg/test"
)

func TestClientMethod(t *testing.T) {
    mockServer := test.NewTestServer(t)

    
    client := SomeClient{URL: mockServer.HttpTest.URL}

    mockServer.Expect(test.ExpectedCall{
        Path:   "/",
        Method: http.MethodPost,
        Headers: map[string]string{
            "Content-Type":  "Application/Json",
            "Authorization": "Basic " + test.BasicAuth("user", "pass"),
        },
        Body:         `{"test": "request", "params": "go here"}`,
        Response:     `{"this is": "the response", "you want to return"}`,
        ResponseCode: http.StatusOK,
    }).Then(...).Then(...) // you can chain as many expectations as you want

    client.Do()

    // the test will fail if any of the server
    // expectations fail, and give a verbose output
}

Running Lambda locally

The project comes with a SAM template file included at sam.yaml this is purely used for local testing purposes as deploying to prod is defined through terraform. The project makefile provides a handy make run-gateway cmd which starts a local gateway forwarding requests to a newly built lambda function.

You can test that your local setup has been a success by curling the /ping route on cmd start.

$ curl 127.0.0.1:3000/ping

will give an output:

{"message":"pong"}

Running Crypto Nodes Locally

If you are looking to interact with some of the crypto APIs in a local environment, take a peek at my other project: docker-crypto which cointains a handy list of dockerfiles for various cryptocurrencies.