Golang REST API - Clean Architecture Principles

Source codes for blog series: https://www.favtuts.com/golang-go-crash-course-series/

install golang

• Download:
  • Access golang.org redirects go.dev
  • Download page: https://go.dev/dl/
  • Install Guide: https://go.dev/doc/install

wget https://go.dev/dl/go1.20.1.linux-amd64.tar.gz

For linux:

1. Remove any previous Go installation by deleting the /usr/local/go folder (if it exists), then extract the archive you just downloaded into /usr/local, creating a fresh Go tree in /usr/local/go:

$ rm -rf /usr/local/go && tar -C /usr/local -xzf go1.20.1.linux-amd64.tar.gz

(You may need to run the command as root or through sudo).

Do not untar the archive into an existing /usr/local/go tree. This is known to produce broken Go installations.

2. Add /usr/local/go/bin to the PATH environment variable. You can do this by adding the following line to your $HOME/.profile or /etc/profile (for a system-wide installation):

export PATH=$PATH:/usr/local/go/bin

Note: Changes made to a profile file may not apply until the next time you log into your computer. To apply the changes immediately, just run the shell commands directly or execute them from the profile using a command such as source $HOME/.profile.

3. Verify that you've installed Go by opening a command prompt and typing the following command:

$ go version

Confirm that the command prints the installed version of Go.

create project folder

cd $GOPATH/src
mkdir golang-mux-api
cd golang-mux-api
go mod init golang-mux-api

Go Modules commands

Initialize the module for the app (from root dir)

$ go mod init github.com/favtuts/golang-mux-api

Edit the existing module file for the new name

$ go mod edit -module github.com/favtuts/golang-mux-api

To rename all imported module from OLD_MODULE to NEW_MODULE

find . -type f -name '*.go' \
  -exec sed -i -e 's,{OLD_MODULE},{NEW_MODULE},g' {} \;

In our cases

find . -type f -name '*.go' \
  -exec sed -i -e 's,golang-mux-api,github.com/favtuts/golang-mux-api,g' {} \;

Download external dependencies

$ go mod download  

The go command uses the go.sum file to ensure that future downloads of these modules retrieve the same bits as the first download (it keeps an initial hash)

Both go.mod and go.sum should be checked into version control.

install Mux library

$ go get -u github.com/gorilla/mux

go: added github.com/gorilla/mux v1.8.0

install Chi library

$ go get -u github.com/go-chi/chi

go: added github.com/go-chi/chi v1.5.4

install Firestore library

$ go get -u cloud.google.com/go/firestore

install MySQL library

$ go get -u github.com/go-sql-driver/mysql

go: added github.com/go-sql-driver/mysql v1.7.0

install MongoDB library

$ go get -u go.mongodb.org/mongo-driver

go: added go.mongodb.org/mongo-driver v1.11.2

install SQLite 3 Library

$ go get -u github.com/mattn/go-sqlite3

go: added github.com/mattn/go-sqlite3 v1.14.16

install Testify library

$ go get -u github.com/stretchr/testify

go: added github.com/stretchr/testify v1.8.2

install Redis library

$ go get -u github.com/go-redis/redis/v7

go: downloading github.com/go-redis/redis/v7 v7.4.1
go: downloading gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15
go: added github.com/go-redis/redis/v7 v7.4.1
go: upgraded gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 => v1.0.0-20190902080502-41f04d3bba15

install AWS SDK for Golang

$ go get -u github.com/aws/aws-sdk-go

go: downloading github.com/aws/aws-sdk-go v1.44.235
go: downloading golang.org/x/sys v0.1.0
go: downloading golang.org/x/net v0.1.0
go: added github.com/aws/aws-sdk-go v1.44.235
go: added github.com/jmespath/go-jmespath v0.4.0
go: upgraded golang.org/x/net v0.0.0-20221014081412-f15817d10f9b => v0.1.0
go: upgraded golang.org/x/sys v0.0.0-20220728004956-3c1f35247d10 => v0.1.0

export Environment variable

export GOOGLE_APPLICATION_CREDENTIALS='/path/to/project-private.key.json'

/home/tvt/FIREBASE/pragmatic-reviews-62551-firebase-adminsdk-l8p5o-65461f8c5b.json

how to get the private key JSON file:

From the Firebase Console: Project Overview -> Project Settings -> Service Accounts -> Generate new private key

build project

go build

run project

go run .

or

go run *.go

run Unit Test

Test (specific test)

$ go test -run NameOfTest

Test (all the tests within the service folder)

$ go test service/*.go

set PORT environment

$ export PORT="8000"
$ echo $PORT

use docker container

To build docker image

$ docker build -t golang-api .

To run docker container

$ docker run -p 8000:8000 golang-api

install Redis on Linux (Ubuntu)

curl -fsSL https://packages.redis.io/gpg | sudo gpg --dearmor -o /usr/share/keyrings/redis-archive-keyring.gpg

echo "deb [signed-by=/usr/share/keyrings/redis-archive-keyring.gpg] https://packages.redis.io/deb $(lsb_release -cs) main" | sudo tee /etc/apt/sources.list.d/redis.list

sudo apt-get update
sudo apt-get install redis

sudo service redis-server start

testing REST API

$ cd controller/
$ go test -v -run TestAddPost
=== RUN   TestAddPost
--- PASS: TestAddPost (0.01s)
PASS
ok      github.com/favtuts/golang-mux-api/controller    0.019s


$ go test -v -run TestGetPosts
=== RUN   TestGetPosts
--- PASS: TestGetPosts (0.01s)
PASS
ok      github.com/favtuts/golang-mux-api/controller    0.034s


$ go test -v -run TestGetPostByID
=== RUN   TestGetPostByID
--- PASS: TestGetPostByID (0.01s)
PASS
ok      github.com/favtuts/golang-mux-api/controller    0.028s

run REST API server with PORT env

$ export PORT=8000
$ go run *.go
Mux HTTP server running on port :8000

run cURL commands to test REST APIs

Create new post

127.0.0.1:6379[1]> KEYS *
(empty array)

curl -v --location 'http://localhost:8000/posts' \
--header 'Content-Type: application/json' \
--data '{
    "title": "Title 1",
    "text": "Text 1"
}'
{"id":7515018121727868634,"title":"Title 1","text":"Text 1"}


127.0.0.1:6379[1]> KEYS *
1) "7515018121727868634"
127.0.0.1:6379[1]> GET 7515018121727868634
"{\"id\":7515018121727868634,\"title\":\"Title 1\",\"text\":\"Text 1\"}"

using AWS CLI works with DynamoDB

Scan all table items

$ aws dynamodb scan --table-name posts --profile=tvt_favtuts