ready, set, go!

This workshop is aimed to provide a fast integration with Go.

Goals

• Install and configure Go;
• Go basics;
• Develop a web application that access a datastore.

Workshop resources

• Chat room: https://tlk.io/mindera
• Download Go: https://golang.org/dl/
• Presentation: https://bit.ly/2KfubQo

Requirements

• Git
• Text Editor or IDE (VSCode with Go extension recommended)
• Docker (recommended)

Running the project

Starting datastore

On the root folder you will need to start redis container with docker-compose

$ docker-compose up -d

Redis will be available on localhost:6379.

Executing source code

On the root folder you need to run the execute script

$ ./scripts/execute.sh

Building application

On the root folder you need to execute the build script

$ ./scripts/build.sh

Executable will be available on app/build/webapp.

Executing application

First you need to execute the build script. Then, on the root folder you need to execute the run script

$ ./scripts/run.sh

Building a docker image with Executable

On the root folder you need to execute docker build command

$ docker build -t webapp .
# after it has created the image, execute it
$ docker run -it --rm -p 8080:8080 webapp

Browse to http://localhost:8080/health and you should receive health endpoint response (it won't work until the challenge is complete).

Workshop timeline summary

• Presentation (40/45min)
• Setup (10/15min)
• Development of web application (45min)
• Questions (10/15min)

Workshop challenge

Setup

• Install Go
• Make sure Go is working by testing go command in your terminal
• Git clone this project
• Compile and execute application
• Pause and check if everyone is one the same step
• Go to http://localhost:8080/health. You should get a Connection refused error.

Development

• Complete the code following steps presented below. Shout any questions, if you don't understand some/any parts.

Step a)

On app/cmd/webapp/main.go you have to initialise the redis client on the init function. If you've used docker-compose.yml to start redis service, use localhost:6379 (address:port) to connect to redis.

Step b)

On app/cmd/web/main.go you need to finish http.Server implementation. Head to http docs and search for a function that allows you to listen and serve content. You should also check for errors.

Step c.1)

On app/internal/webapp/routes.go you need to complete RegisterRoutes() and add one http route (PUT) for any given path.

Step c.2)

On app/internal/webapp/handler.go you need to implement a function that given a key (request URL path) and a value (request body), it should add it to the datastore. If it's successful return the request body, if not http.StatusBadRequest (header).

Step c.3)

On app/internal/webapp/routes.go you need to update RegisterRoutes() and add the implemented function on c.2 as a handler of PUT.

Step d)

On app/internal/webapp/handler.go you need to complete health function: return {"status": "OK"} if connection with datastore if ok; return {"status": "FAIL", "error": errorMessage}.

Step e.1)

On app/internal/webapp/handler.go you should implement a logger handler and it should send to stdout:

• {request end date} | {request Method} | {time to execute in msec} | {request path}

As an example: 2018/11/20 18:50:12 | GET | 0.01344ms /health

Step e.2)

On app/internal/webapp/routes.go you should add the logger handler implemented on e.1) to each mux handlers.

---

Expected results

• GET /health endpoint should return OK if datastore is up and running; and should return FAIL if datastore is down.
• GET /{key} endpoint should return the value of the {key} on the datastore.
• PUT /{key} endpoint should accept a {body}, save on the datastore and on success should return it.

BONUS

• All http methods (GET and PUT) should be logged to stdout.