2. My first feature branch¶

Now that we’ve got our repo forked and cloned with our git-flow skeleton in place, we can see the flow in action by completing our first feature!

Calling our API endpoints¶

Let’s try and figure out what hbaas API is doing after all, then!

Make sure the API is running with ./hbaas-server if it isn’t already and let’s check out what the root endpoint gives us:

curl -s localhost:8000 | jq

{
	"message": "Welcome! Try sending a request to '/name/{some-name}' to get started!"
}

It looks like the endpoint /name/{value} is a valid endpoint, so let’s try giving that a go:

curl -s localhost:8000/name/Benedict%20Cumberbatch | jq

{
	"message": "Happy birthday Benedict Cumberbatch!"
}

Now we can see what the our API is doing - it’s providing Happy Birthday as a Service (HBaaS)!

Adding our feature!¶

So we’ve got our endpoint to wish anyone we want happy birthday, but we want to be able to do more than that!

We’re going to add a new endpoint to this API that will enable us to wish people a happy birthday by specifying a date - the API will then look up all the people with the specified birthday and wish them a happy birthday!

Luckily for us, most of the hard work for this feature is already there - if you look at handlers/birthday.go, you’ll see the code that implements the endpoints that we’ve got at the moment.

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	"github.com/labstack/echo/v4"

	"hartree.stfc.ac.uk/hbaas-server/context"
)

type BirthdayHandler struct {
	Context context.Context
}

func (h BirthdayHandler) registerEndpoints(g *echo.Group) {
	g.GET("", h.sayHello)
	g.GET("name/:name", h.sayHappyBirthdayToName)
}

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package context

import "time"

type BirthDay struct {
	Day   int
	Month time.Month
}

func NewBirthDay(date time.Time) BirthDay {
	return BirthDay{
		Day:   date.Day(),
		Month: date.Month(),
	}
}

type Context struct {
	PeopleByBirthday map[BirthDay][]string
}

rg -F 'map[BirthDay][]string'

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package data

import _ "embed"

//go:embed people.csv
var PeopleCSV string

Okay, now that we’ve found our mapping, let’s add another endpoint for our date-based happy birthday wishes. Add to the file handlers/birthday.go the highlighted lines:

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package handlers

import (
	"fmt"
	"net/http"
	"strings"
	"time"

	"github.com/labstack/echo/v4"

	"hartree.stfc.ac.uk/hbaas-server/context"
)

type BirthdayHandler struct {
	Context context.Context
}

func (h BirthdayHandler) registerEndpoints(g *echo.Group) {
	g.GET("", h.sayHello)
	g.GET("name/:name", h.sayHappyBirthdayToName)
	g.GET("date/:date", h.sayHappyBirthdayByDate)
}

func (h BirthdayHandler) sayHello(c echo.Context) error {
	message := fmt.Sprintf("Welcome! Try sending a request to '/name/{some-name}' to get started!")
	return c.JSON(
		http.StatusOK,
		NewAPIMessage(message),
	)
}

func (h BirthdayHandler) sayHappyBirthdayToName(c echo.Context) error {
	name := c.Param("name")
	message := fmt.Sprintf("Happy birthday %s!", name)
	return c.JSON(
		http.StatusOK,
		NewAPIMessage(message),
	)
}

func (h BirthdayHandler) sayHappyBirthdayByDate(c echo.Context) error {
	date := c.Param("date")

	dateTime, err := time.Parse("2-January", date)
	if err != nil {
		return echo.ErrBadRequest
	}

	message := "It doesn't look like I know of anyone with that birthday!"

	birthDay := context.NewBirthDay(dateTime)
	names, exists := h.Context.PeopleByBirthday[birthDay]
	if exists {
		if len(names) > 1 {
			names[len(names)-2] = fmt.Sprintf(
				"%s and %s",
				names[len(names)-2],
				names[len(names)-1],
			)
			names = names[0 : len(names)-1]
		}
		message = fmt.Sprintf(
			"Happy birthday to %s!",
			strings.Join(names, ", "),
		)
	}

	return c.JSON(http.StatusOK, NewAPIMessage(message))
}

The specifics of this code isn’t important for this particular workshop, other than that we’re adding an endpoint at /:date (where :date represents a variable passed through in the endpoint path) and that this endpoint uses our h.Context.PeopleByBirthday mapping to look up people who have the birthday specified by the path parameter.

Now that we’ve got that endpoint added, we can recompile our server and try it out!

task
./hbaas-server

In another terminal tab:

curl -s localhost:8000/date/11-November

{
  "message": "Happy birthday to Leonardo DiCaprio, Demi Moore and Stanley Tucci!"
}

Try it out with a few more dates - there’s almost 300 people listed in there!

Now that this feature is implemented and working, we’re ready to merge it back into the dev branch:

# Make sure we're branching our feature branch out from dev
git checkout dev

# Create our new feature branch
git checkout -b feature/add-happy-birthday-by-date

git add handlers/birthday.go
git commit -m "Add endpoint for wishing people happy birthday by date."

git push --set-upstream origin feature/add-happy-birthday-by-date

If you now go to your repository in GitLab, you should create a merge request from this new feature branch to the dev branch.

At this point, if you’re working in a wider team, you’ll want to assign a designated teammate to review the code and approve it. Once it’s been approved, you can merge in the changes.