database design

https://dbdiagram.io/d/651932d4ffbf5169f0cf306d

Set up POSTGRES with docker

# download postgres image
$ docker pull postgres

# run container
# docker run --name <container-name> -p <host-port:container-port> -e POSTGRES_PASSWORD=postgres -d <image-name>
# -d flag tell the docker run container in the background
# -e flag stand for environment
$ docker run --name postgres -p 5432:5432 -e POSTGRES_PASSWORD=postgres -d postgres

# Stop container
$ docker stop postgres

# start container
$ docker start postgres

Migrate database

Install golang-migrate

$ curl -L https://packagecloud.io/golang-migrate/migrate/gpgkey | sudo  apt-key add -

$ echo "deb https://packagecloud.io/golang-migrate/migrate/ubuntu/ $(lsb_release -sc) main" | sudo tee  /etc/apt/sources.list.d/migrate.list

$ sudo apt-get update
$ sudo apt-get install -y migrate

Using golang-migrate to create migrate up and down file

$ mkdir -p db/migration

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

Note

Composition instead of inheritance

Database transaction

ACID property

Atomicity - Consistency - Isolation - Durability

Isolation level

Read phenomena

Dirty read: A transaction read data written by other concurrent uncommited transaction
Non-repeatable read: A transaction read same row twice and sees different values because its has been modify by other concurrent commited transaction
Phantom read: The same Non-repeatable read but for mutiple rows
Serialization anomaly: The result of a group of concurrent commited transaction is impossible to achieve if we try to run them sequentially in any order without overlapping

4 Standard Isolation level

Read uncommitted
Read committed
Repeatable read
Serializable

GIN

Postman: https://api.postman.com/collections/24261537-a1befa63-2b4e-439b-b451-57359548bdf8?access_key=PMAT-01HD5MEECR9EAJF3PVJ166HTYX

Docker

Run 2 containers in the same network The problem is in the ENV file the link of postgres database is: DB_SOURCE=postgres://postgres:postgres@localhost:5432/simple_bank?sslmode=disable. But in the simplebank container doesn't know the localhost because postgres container and simplebank container run separate IP. Run docker inspect <container_name> to check the IP address. The easy way to solve it is change the DB_SOURCE=postgres://postgres:postgres@localhost:5432/simple_bank?sslmode=disable to DB_SOURCE=postgres://postgres:postgres@<postgres_IP>:5432/simple_bank?sslmode=disable But when to restart postgres container it may be run on different IP.

The best solution is creaate your own net work in docker and run both of its in this network. And in this net work it doesn't use IP to indentify it use the container_name

# create new network
$ docker network create bank-network

# connect postgres to this network
$ docker network connect bank-network postgres

# run simplebank container in this network
$ docker run --name simplebank -p 8080:8080 --network=bank-network -e DB_SOURCE="postgres://postgres:postgres@postgres:5432/simple_bank?sslmode=disable" simplebank:latest

## successfull

GRPC

Define Api and datastructure: Using ptrotocol buffer to generate go code for grpc server, client ref: https://grpc.io/docs/languages/go/quickstart/ Using Evans grpc cli to interact with grpc server ref: https://github.com/ktr0731/evans

phanquocky/Simple_Bank