README.md

Gin Instrumentation Example

This is an example of producing distributed traces using the SignalFx Tracing Library for Go. This example provides an instrumented API server that serves Battleship game to show some basic patterns in accessing the instrumentations of a Gin application and MongoDB drivers. You can either play by calling exposed API endpoints directly or run a simulated player.

Prerequisite

This example requires a running MongoDB instance that the server can access. You can start a docker container by running this command.

$ docker run -d --name mongo -p 27017:27017 mongo

Configuration

A default set of configuration is included in server/server.go. Modify as needed before running. Note that you can choose MongoDB driver to use by changing MongoDriver config.

// server.go

const (
	// ServiceName contains name of this service. This will show up on traces
	ServiceName = "signalfx-battleship"
	// TracingEndpoint contains a url to send traces
	TracingEndpoint = "http://localhost:9080/v1/trace"
	// Port that the app runs
	Port = 3030
	// MongoDriver is mongodb driver type. Selections are "mgo" | "mongo"
	MongoDriver = "mongo"
	// MongoHost is database hostname
	MongoHost = "localhost"
	// MongoPort is database port number
	MongoPort = 27017
	// MongoDbName is database name
	MongoDbName = "bships"
)

Start Service

To run this example locally and send traces to your available Smart Agent or Gateway, please clone this repository and from this directory do the following:

$ cd server
$ go get
$ go run server.go

How to Play

You can start a new game and get the gameId by calling POST /game endpoint. Once you get a gameId, call POST /game/[gameId] endpoint with a JSON body as shown below.

{
  "x": 1,
  "y": 0
}

Then, the server will return a response with the game status.

{
    "board": [
        [
            0,
            0,
            0
        ],
        [
            1,
            0,
            0
        ],
        [
            0,
            0,
            0
        ]
    ],
    "finished": false,
    "status": {
        "turnsPlayed": 1,
        "shipsHit": 0,
        "shipsLeft": 2
    }
}

finished flag will turn on when all the ship spots are found.

Using the simulated player

You can also automate the sequence of API calls of finishing one game by running player/player.go