playing with aws/goroutines

aws_play.go

// Attempt at provisioning aws instances via goroutines/channels
// Start playing with porting microarmy
package main

import (
    "launchpad.net/goamz/aws"
    "launchpad.net/goamz/ec2"
)

// Probably wasn't necessary to extract this, but hey
func setupInstanceTypes() ec2.RunInstances {
    options := ec2.RunInstances{
        ImageId:      "ami-ccf405a5",
        InstanceType: "t1.micro",
    }
    return options
}

// Fire up the instances, drop the response on a channel
func runInstances(options *ec2.RunInstances, e **ec2.EC2, resp_out chan ec2.RunInstancesResp)  {
    resp, err := e.RunInstances(options)
    if err != nil {
        panic(err)
    }
    resp_out <- *resp
    // Close out the channel so our consumers know we're done
    close(resp_out)
}

// Listen for a message off the channel, notify us when we're done
func notifyComplete(resp_in chan ec2.RunInstancesResp, done chan<- bool) {
    // Holy shit I don't remember how to dereference pointers
    resp := <- *(&resp_in)

    for _, instance := range resp.Instances {
        println("Now running", instance.InstanceId)
    }
    println("Make sure you terminate instances to stop the cash flow.")

    done <- true
}

// I don't know how computers work
func main() {
    auth, err := aws.EnvAuth()
    if err != nil {
        panic(err)
    }
    e := ec2.New(auth, aws.USEast)

    // Setup our channels
    responseChan := make(chan ec2.RunInstancesResp)
    done := make(chan bool)

    options := setupInstanceTypes()

    // Should be able to fire off as many of these as you want, will scale
    go runInstances(&options, &e, responseChan)
    go notifyComplete(responseChan, done)

    <-done
}

Show me how to go better.