=govolutto=

Golang version of money transfer REST API (see link)

Features

• Written in Go ❤️
• Lightweight executable: ~4.5MB
• Production ready: Dockerfile + k8s yaml

Installation

go get github.com/google/wire/cmd/wire
wire ./src

go test -v ./test
go test ./test -bench=. -run=XXX

go build -ldflags="-s -w" -o govolutto
go build -ldflags="-s -w" -o govolutto.zip && upx govolutto.zip

API

• Get balance: GET /v1/balance/{username}
• Transfer money: POST /v1/transfer

{
  "from": "scrooge",
  "to": "daisy",
  "amount": 100.0
}

• Health endpoint: GET /v1/health
• Metrics endpoint: GET /v1/metrics

Usage

GIN_MODE=debug ./govolutto
GIN_MODE=release ./govolutto.zip

http :8080/v1/balance/daisy | jq
{
  "balance": "100",
  "username": "daisy"
}

http :8080/v1/balance/scrooge | jq
{
  "balance": "10000",
  "username": "scrooge"
}

http POST :8080/v1/transfer <<< '{"from": "scrooge", "to": "daisy", "amount": 10000.0}' | jq
{
  "amount": "10000",
  "from": "scrooge",
  "success": "true",
  "to": "daisy"
}

http POST :8080/v1/transfer <<< '{"from": "daisy", "to": "scrooge", "amount": 10000.0}' | jq
{
  "amount": "10000",
  "from": "daisy",
  "success": "true",
  "to": "scrooge"
}

Load test

echo "POST http://localhost:8080/v1/transfer" | vegeta attack -body payload.json -header="Content-Type: application/json" -rate=500 -duration=5s | tee results.bin | vegeta report
Requests      [total, rate, throughput]  2500, 500.20, 500.18
Duration      [total, attack, wait]      4.998199772s, 4.997979158s, 220.614µs
Latencies     [mean, 50, 95, 99, max]    387.021µs, 212.602µs, 372.705µs, 5.781057ms, 28.793267ms
Bytes In      [total, mean]              157500, 63.00
Bytes Out     [total, mean]              142500, 57.00
Success       [ratio]                    100.00%
Status Codes  [code:count]               200:2500
Error Set:

cat results.bin | vegeta report -type="hist[0,1ms,5ms,10ms,20ms,50ms,100ms,500ms,1000ms]"
Bucket           #     %       Histogram
[0s,     1ms]    2460  98.40%  #########################################################################
[1ms,    5ms]    13    0.52%
[5ms,    10ms]   10    0.40%
[10ms,   20ms]   11    0.44%
[20ms,   50ms]   6     0.24%
[50ms,   100ms]  0     0.00%
[100ms,  500ms]  0     0.00%
[500ms,  1s]     0     0.00%
[1s,     +Inf]   0     0.00%

Docker

• Lightweight Docker image (4.5MB)
• See Dockerfile

wire ./src
GOOS=linux go build -ldflags="-s -w" -o build/govolutto.zip && upx build/govolutto.zip
docker build -t maslick/govolutto .
docker run -d -p 8081:8080 maslick/govolutto

http http://`docker-machine ip default`:8081/v1/balance/daisy | jq
{
  "balance": "100",
  "username": "daisy"
}

Kubernetes

kubectl apply -f k8s/deployment.yaml
kubectl get all -l project=govolutto
kubectl port-forward govolutto-api-5b58b69647-877qd 8083:8080
http :8083/v1/health

Heroku

$ git clone https://github.com/maslick/govolutto.git
$ cd govolutto

$ export HEROKU_APP_NAME=hello-world-app
$ heroku login
$ heroku create $HEROKU_APP_NAME
$ git push heroku master
$ heroku config:set GIN_MODE=release
$ open https://$HEROKU_APP_NAME.herokuapp.com/v1/health

Links

• upx
• httpie
• vegeta
• jq