tut-gobank

The contents below are my guide for setup, development, and deployment following the Tech School Backend master class Golang, Postgres, Docker

Setting up

1. Docker Desktop
2. Docker Postgres

docker run --name postgres13 -p 5432:5432 -e POSTGRES_USER=root -e POSTGRES_PASSWORD=Ulyanin123 -d postgres:12-alpine
docker exec -it postgres13 createdb --username=root --owner=root simple_bank

3. Golang and libraries
   • Golang Migrate

Linux Install

curl -L https://github.com/golang-migrate/migrate/releases/download/v4.14.1/migrate.linux-amd64.tar.gz | tar xvz
sudo mv migrate.linux-amd64 /usr/bin/
which migrate

Mac Install

brew install golang-migrate

Setup

mkdir -p db/migration
migrate create -ext sql -dir db/migration -seq init_schema
migrate -path db/migration -database "postgresql://root:Ulyanin123@localhost:5432/simple_bank?sslmode=disable" -verbose up

Creating new migration

migrate create -ext sql -dir db/migration -seq add_users

• Viper

go get github.com/spf13/viper

• Mockgen

go get github.com/golang/mock/mockgen@v1.5.0
mockgen --version

4. SQLC

• Download SQLC.

sudo apt update && sudo apt -y upgrade
wget -c https://github.com/kyleconroy/sqlc/releases/download/v1.8.0/sqlc-v1.8.0-linux-amd64.tar.gz -O - | tar -xz

Move the downloaded file to a directory enabled in $Path i.e. $GOPATH/bin.

• Initilize SQLC

sqlc init

It will create sqlc.yaml file, configure as you like. Then:

sqlc generate

5. Golang Postgres Library PQ

go get github.com/lib/pq

Tools

Entity-Relationship Diagrams

dbdiagram

Docker Commands Guide

docker build --help

# downloading docker image from store
docker pull postgres:12-alpine

# building image from local
docker build -t simplebank:latest .

# to list all images
docker images

# to remove old image
docker rmi 23cec85a1a89

# to run and create image and container with IP Address
docker run --name simplebank -p 8080:8080 -e DB_SOURCE="postgresql://root:Ulyanin123@172.17.0.2:5432/simple_bank?sslmode=disable" -e GIN_MODE=release simplebank:latest

# to run and create image and container with network name
docker run --name simplebank --network simplebank-network -p 8080:8080 -e DB_SOURCE="postgresql://root:Ulyanin123@postgres13:5432/simple_bank?sslmode=disable" -e GIN_MODE=release simplebank:latest

# to start existing container
docker start simplebank

# to stop existing container
docker stop simplebank

# to check containers status
docker ps -a

# to remove container by name
docker rm simplebank

# to inspect container details e.g. Networks IP address
docker container inspect postgres13

# to see network details
docker network ls
docker network inspect bridge

# to create a new network
docker network --help
docker network create simplebank-network

# to connect your container to a specific network
docker network connect --help
docker network connect simplebank-network postgres13
docker network inspect simplebank-network
docker inspect postgres13

# executing commands inside container as root user with selected database
docker exec -it postgres13 psql -U root simple_bank
\q

# executing commands inside container as root user
docker exec -it postgres13 psql -U root

# executing commands inside container using bash shell
docker exec -it postgres13 /bin/sh
createdb --username=root --owner=root simple_bank
psql simple_bank
\q
dropdb simple_bank
exit

# executing commands in container directly in shell
docker exec -it postgres13 createdb --username=root --owner=root simple_bank

DEVELOPMENT Steps

1. Migration

Create the folder where you want to put your migration files. E.g. db/migration

mkdir -p db/migration

Create a new instance of your migration. E.g. init_schema, add_users This will create an up and down version file in your migration folder. Edit them to create and delete the DB objects.

migrate create -ext sql -dir db/migration -seq init_schema

Run migration up or down, set your connection string.

migrate -path db/migration -database "postgresql://root:Ulyanin123@localhost:5432/simple_bank?sslmode=disable" -verbose up

migrate -path db/migration -database "postgresql://root:Ulyanin123@localhost:5432/simple_bank?sslmode=disable" -verbose down

2. SQLC - to autogenerate creation of Golang objects.

Initilize SQLC, It will create sqlc.yaml file.

sqlc init

Configure your sqlc.yaml. E.g:

version: "1"
packages:
  - name: "db"
    path: "./db/sqlc"
    queries: "./db/query/"
    schema: "./db/migration/"
    engine: "postgresql"
    emit_json_tags: true
    emit_prepared_queries: false
    emit_interface: true
    emit_exact_table_names: false
    emit_empty_slices: true
    json_tags_case_style: "camel"

Generate SQLC, it will create Golang objects based on the files in your migration and queries folder.

sqlc generate

3. Mock db

For testing purpose, this will create a mockversion of your db.

mockgen -package mockdb -destination db/mock/store.go github.com/aambayec/tut-gobank/db/sqlc Store

DEPLOYMENT

1. Create Dockerfile then edit in the root folder

# Build stage
FROM golang:1.16.5-alpine3.13 AS builder
WORKDIR /app
COPY . .
RUN go build -o main main.go
RUN apk --no-cache add curl
RUN curl -L https://github.com/golang-migrate/migrate/releases/download/v4.14.1/migrate.linux-amd64.tar.gz | tar xvz

# Run stage
FROM alpine:3.13
WORKDIR /app
COPY --from=builder /app/main .
COPY --from=builder /app/migrate.linux-amd64 ./migrate
COPY app.env .
COPY start.sh .
COPY wait-for.sh .
COPY db/migration ./migration

EXPOSE 8080
CMD [ "/app/main" ]
ENTRYPOINT [ "/app/start.sh" ]

2. Create docker-compose.yaml in the root folder

version: "3.9"
services:
  postgres:
    image: postgres:12-alpine
    environment:
      - POSTGRES_USER=root
      - POSTGRES_PASSWORD=Ulyanin123
      - POSTGRES_DB=simple_bank
  api:
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - "8080:8080"
    environment:
      - DB_SOURCE=postgresql://root:Ulyanin123@postgres:5432/simple_bank?sslmode=disable
    depends_on:
      - postgres
    entrypoint: ["/app/wait-for.sh", "postgres:5432", "--", "/app/start.sh"]
    command: ["/app/main"]

Run.

docker compose up

2. Create start.sh in the root directory.

#!/bin/sh

set -e

echo "run db migration"
/app/migrate -path /app/migration -database "$DB_SOURCE" -verbose up

echo "start the app"
exec "$@"

Make start.sh executable

chmod +x start.sh

Download the wait-for latest release then rename to wait-for.sh, move the the root folder Make wait-for.sh executable

chmod +x _wait-for.sh

Run

docker compose up