Bitcoin Blockchain API

A simple REST API developed with Go, Gin, PostgreSQL, and GORM to mimic operations that may occur on a Bitcoin Blockchain. This includes mining blocks, creating address (or wallets) and creating and viewing transactions.

The blockchain implementation heavily relies on this blog post: https://jeiwan.net/posts/building-blockchain-in-go-part-1/

---

How to run the app

In the root directory containing the docker-compose.yml file, run:

1. docker-compose down
2. docker-compose -f docker-compose.yml up

To recreate containers, run docker-compose up --build

Note: You may need to clear any old postgres containers or volumes. To start fresh, you can run

docker stop $(docker ps -qa) && docker system prune -af --volumes

Then run command 2) above.

The .env file You may modify the following environment variables to your choosing:

• POSTGRES_HOST_NAME - The hostname or container name for the running postgres server.
• POSTGRES_USER - The username to use for the connection.
• POSTGRES_PASSWORD - The password to use for the connection.
• POSTGRES_DB - The database to use once connected.

By default,

• POSTGRES_HOST_NAME=database
• POSTGRES_USER=postgres
• POSTGRES_PASSWORD=pass
• POSTGRES_DB=blockchain

---

After running the above commands, you should see that two containers get spun up with docker ps:

This is a sample of the container log for the blockchain_app container:

Alternatively, if you have docker hub, you may pull the image from docker and run it as a container. The image name is brucetieu/blockchain:latest, and you can run docker pull brucetieu/blockchain:latest to pull the image.

Additionally, you will need to create a network and attach a postgresql container so that the image you will run can communicate with it. Here are the commands to do that.

1. Create the network

docker network create <your-network-name>

2. Start a posgresql container and attach it to the network

docker run -d \
> --network <your-network-name> --network-alias <your-network-alias> \
> -v <your-volume-name>:/var/lib/postgresql/data \
> -e POSTGRES_USER=<your-postgres-user> \
> -e POSTGRES_PASSWORD=<your-postgres-pass> \
> -e POSTGRES_DB=<your-postgres-db> \
> --name <container-name> \ 
> postgres:14

3. Run the app with postgresql. The blockchain app supports the setting of several environment variables to specify postgres connection settings. They are:

   • POSTGRES_HOST_NAME - The hostname for the running postgres server. This is the name of the postgres container that was created in step 2.
   • POSTGRES_USER - The username to use for the connection.
   • POSTGRES_PASSWORD - The password to use for the connection.
   • POSTGRES_DB - The database to use once connected.

docker run -dp 5000:5000 \
> --network <your-network-name> \
> -e POSTGRES_HOST_NAME=<postgres-container-name> \
> -e POSTGRES_USER=<your-postgres-user> \
> -e POSTGRES_PASSWORD=<your-postgres-pass> \
> -e POSTGRES_DB=<your-postgres-db> \
> brucetieu/blockchain:latest

The service will be running on port 5000 by default. To test that the API is healthy, make a request to GET localhost:5000/bitcoin. You should see the following response:

"Blockchain healthy"

Now, you should be able to make requests to the API. Refer to the swagger for more information on the available endpoints, or visit localhost:5000/swagger/index.html once the service is running.

---

How to access the Postgres CLI (psql) inside of the running Postgres container

In this project we use a postgres container for data persistence. In another terminal, run the following commands to get inside that container:

1. docker ps

   

   We will need the container name running postgres, e.g. database in the photo.

2. Connect to postgres in the running container with docker exec -it <NAME_OF_RUNNING_POSTGRES_CONTAINER> psql -U <POSTGRES_USER> <POSTGRES_DB>

   POSTGRES_USER and POSTGRES_DB are optional environment variables you can set. By default, these values are postgres and blockchain respectively.

   
   

   The data will be stored in the blockchain database, or the database name you specified via the POSTGRES_DB environment variable. Refer to the psql docs for all available psql commands.