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

Bharat — Tue, 29 Aug 2023 19:37:18 +0000

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)

DEV Community: Bharat