Microservices in Go Lang with Postgres (Local, Docker to Render Public hosting)

This project will summarize the steps to create a microservice using Golang and Postgresql.
We will be using 4 different data models each implementing CRUD operations.
The structure of the project will be like -

• internal/database - This will contain the database connection and the schema and data files.
• internal/models - This will contain the data models.
• internal/db_errors - This will contain the error handling for the database.
• internal/server - This will contain the server and the main function.

Elaborated schema for the project using E-R diagram

The following are dependencies we will be using, along with the steps to run your project locally.

Link to my github repo for the code - https://github.com/bindian0509/microservices-with-golang

Pre-requisites (for mac OS ventura)

• Install httpie (https://httpie.org/) for testing the API
  • brew install httpie
• Install docker (https://docs.docker.com/docker-for-mac/install/)
  • brew cask install docker
• VScode with Go extension (https://code.visualstudio.com/docs/languages/go)
  • brew cask install visual-studio-code
• Install golang (https://golang.org/doc/install)
  • brew install go

Use getting started for creating Postgres container

• Create a dir in your home folder called data-postgres-go under docker-vols
  • mkdir -p ~/docker-vols/data-postgres-go

• Create a postgres container
  

  docker run -d --rm \
      --name local-pg \
      -e POSTGRES_PASSWORD=postgres \
      -p 5432:5432 \
      -e PGDATA=/var/lib/postgresql/data/pgdata \
      -v /Users/<user-name>/docker-vols/data-postgres-go:/var/lib/postgresql/data \
  postgres
  

• Login via psql

  • docker exec -it local-pg psql -U postgres

• Create database schema via schema.sql

  • psql -U postgres -f schema.sql

• Insert data to the database via data.sql

  • psql -U postgres -f data.sql

Setting up the go project

• Create a directory called microservices-with-golang in your home folder
  • mkdir -p ~/microservices-with-golang
  • cd ~/microservices-with-golang
• Use go mod init to create a go module
  • go mod init github.com/<github-username>/microservices-with-golang
• Use go mod tidy to download the dependencies
  • go mod tidy
• To start the project run
  • go run main.go voila you have your project up and running

   ____    __
  / __/___/ /  ___
 / _// __/ _ \/ _ \
/___/\__/_//_/\___/ v4.11.1
High performance, minimalist Go web framework
https://echo.labstack.com
____________________________________O/_______
                                    O\
⇨ http server started on [::]:8080

Testing Microservices

Checking the database connection and liveness probe

• To start the server
  • go run main.go
• To check everything is working fine
  • http :8080/readiness
  • http :8080/liveness
• Expected output

    HTTP/1.1 200 OK
    Content-Length: 16
    Content-Type: application/json; charset=UTF-8
    Date: Tue, 22 Aug 2023 11:30:52 GMT

    {
        "status": "OK"
    }

Testing Get All customer API endpoint (GET)

• To get all customers
  • http :8080/customers

[
    {
        "address": "556 Lakewood Park, Bismarck, ND 58505",
        "customerId": "e2579031-41f8-4c1b-851d-d05dd0327230",
        "emailAddress": "penatibus.et@lectusa.com",
        "firstName": "Cally",
        "lastName": "Reynolds",
        "phoneNumber": "(901) 166-8355"
    },
    {
        "address": "4829 Badeau Parkway, Chattanooga, TN 37405",
        "customerId": "8db81915-7955-47ac-abf1-fa3a3f27e0a3",
        "emailAddress": "nibh@ultricesposuere.edu",
        "firstName": "Sydney",
        "lastName": "Bartlett",
        "phoneNumber": "(982) 231-7357"
    },
    ...
]

• To get customer from emailAddress (search API) (GET)
  • http :8080/customers emailAddress=="magna.Phasellus@Phasellus.net"

HTTP/1.1 200 OK
Content-Length: 223
Content-Type: application/json; charset=UTF-8
Date: Tue, 22 Aug 2023 13:26:37 GMT

[
    {
        "address": "602 Sommers Parkway, Norfolk, VA 23520",
        "customerId": "44f82d9d-b0a6-49b2-ac04-cb05b4cbf189",
        "emailAddress": "magna.Phasellus@Phasellus.net",
        "firstName": "Brock",
        "lastName": "Case",
        "phoneNumber": "(544) 534-1984"
    }
]

Testing create customer API endpoint (POST)

• To create a new customer
  • http POST :8080/customers firstName=John lastName=Reese emailAddress="john@root.com" phoneNumber="515-555-1235" address="36 ChinaTown, Borivali East, Mumbi, MH, INDIA"

    HTTP/1.1 201 Created
    Content-Length: 210
    Content-Type: application/json; charset=UTF-8
    Date: Tue, 22 Aug 2023 18:28:38 GMT

    {
        "address": "36 ChinaTown, Borivali East, Mumbi, MH, INDIA",
        "customerId": "68fb0b27-1e9a-4ce8-81ac-f41cc1e3f5d6",
        "emailAddress": "john@root.com",
        "firstName": "John",
        "lastName": "Reese",
        "phoneNumber": "515-555-1235"
    }

Testing Get customer from Id API endpoint (GET)

• To get customer with customerId
  • http :8080/customers/8db81915-7955-47ac-abf1-fa3a3f27e0a3

    HTTP/1.1 200 OK
    Content-Length: 225
    Content-Type: application/json; charset=UTF-8
    Date: Wed, 23 Aug 2023 11:10:49 GMT

    {
        "address": "4829 Badeau Parkway, Chattanooga, TN 37405",
        "customerId": "8db81915-7955-47ac-abf1-fa3a3f27e0a3",
        "emailAddress": "nibh@ultricesposuere.edu",
        "firstName": "Sydney",
        "lastName": "Bartlett",
        "phoneNumber": "(982) 231-7357"
    }

Testing Update customer API endpoint (PUT)

• To update customer with customerId
  • http PUT :8080/customers/e2579031-41f8-4c1b-851d-d05dd0327230 address="556 Lakewood Park, Bismarck, ND 58505" customerId="e2579031-41f8-4c1b-851d-d05dd0327230" emailAddress="penatibus.et@lectusa.com" firstName="Ryan" lastName="Reynolds" phoneNumber="(901) 166-8355"

    HTTP/1.1 200 OK
    Content-Length: 218
    Content-Type: application/json; charset=UTF-8
    Date: Fri, 25 Aug 2023 19:04:49 GMT

    {
        "address": "556 Lakewood Park, Bismarck, ND 58505",
        "customerId": "e2579031-41f8-4c1b-851d-d05dd0327230",
        "emailAddress": "penatibus.et@lectusa.com",
        "firstName": "Ryan",
        "lastName": "Reynolds",
        "phoneNumber": "(901) 166-8355"
    }

Testing Delete customer API endpoint (DELETE)

• To update customer with customerId
  • http DELETE :8080/customers/8db81915-7955-47ac-abf1-fa3a3f27e0a3

    HTTP/1.1 205 Reset Content
    Content-Length: 0
    Date: Fri, 25 Aug 2023 19:31:23 GMT

Running the same project with docker image (using Dockerfile)

• Step 1: Build the docker image for the application
  • docker build -t microservices-with-golang .
• Step 2: Run the docker image
  • docker run -e env=docker --env-file db.docker.env --network host --name microservices-with-golang-app microservices-with-golang
• Step 3: Since this container is not exposed to outside world we can login inside it and test the API
  • docker exec -it microservices-with-golang-app sh
  • http :8080/liveness (this will work fine since the docker file already has apk add httpie)

Production release of the application using Render.com free tiers

• Sign up for render.com using github or other options
• At first we need to spinup a database service (PostgreSQL)
  • Click on create a new database
  • Select the free tier
  • Select the region
  • Select the database name
  • Select the database password
  • Click on create database
• Use psql command option to be copied and dump the files to prod db via following commands
  • PGPASSWORD=<your-db-password> psql -h xxx-a.singapore-postgres.render.com -U <user_name> <db_name> < schema.sql
  • PGPASSWORD=<your-db-password> psql -h xxx-a.singapore-postgres.render.com -U <user_name> <db_name> < data.sql
• Create a new web service
  • Select the github repo
  • Select the branch
  • Select the docker file path
  • Select the port
  • Select the environment variables
    • Refer to db.env file for list of args
    • sslmode=require is for production db cluster
  • Select the free tier
  • Click on create web service
• Once the web service is created you can see the logs and the application running on the url provided by render.com
  • My cluster https://microservices-with-golang.onrender.com/liveness (liveness probe)