build-go-slalom.md

Run go-slalom

go-slalom demonstrates how to create a basic service to run in kubernetes. The service includes the following:

• handles interrupts expected from kubernetes
• basic liveness and readiness end-points
• endpoints for enabling/disabling readiness and liveness endpoints
• endpoint for basic service information

build go-slalom

First lets clone and build go-slalom locally

# tell go to use modules (still opt-in feature)
export GO111MODULE=on

# create a directory to checkout to
mkdir /tmp/slalom
cd /tmp/slalom
 
# clone go-slalom and cd to it
git clone git@github.com:slalom/go-slalom.git
cd go-slalom

# build
go build

go-slalom cli

go-slalom includes a basic cli built using cobra. It is common in go to build a cli for starting a service and/or administering the service. Lets check it out

# run to see cli help message
./go-slalom help

Notice that go-slalom main just calls cmd.Execute()

func main() {
  cmd.Execute()
}

The package cmd contains the commands. The file root.go implements the root command and the other files implement sub commands. corba provides a clean cli.

start go-slalom

One of the cli commands is start. Run it to start ther server

./go-slalom start

You should see logging similar to below.

{"level":"info","msg":"Starting server...","service":"api","time":"2019-05-09T13:22:03-07:00"}

In a separate console run curl localhost:8008/version. You should see similar output

{
  "commit": "unknown",
  "version": "0.0.1"
}

go-slalom server

The start command (in cmd package) calls

api.NewServer().ListenAndServe()

See pkg/api/server.go. It does the following:

• creates a signal handler to handle interrupts
• registers handler functions
• create and run the server in background using a goroutine
• enable probes to tell kubernetes it is ready for traffic
• wait for an interrupt
• disable probes to tell kubernetes it is unavailable
• gracefully shutdown server