examples/databases/postgres/README.md

async_pg example

This example illustrates

• tokio_postgres
• use of tokio_pg_mapper for postgres data mapping
• deadpool_postgres for connection pooling
• dotenv + config for configuration

Instructions

NOTE:

You may need to ensure that you are running the commands with the correct SQL user. On many Linux distributions you may prefix the shell commands with sudo -u postgres

1. Create database user

   createuser -P test_user
   

   Enter a password of your choice. The following instructions assume you used testing as password.

   This step is optional and you can also use an existing database user for that. Just make sure to replace test_user by the database user of your choice in the following steps and change the .env file containing the configuration accordingly.

   An alternative using SQL:

   CREATE USER test_user WITH PASSWORD 'testing';
   

2. Create database

   createdb -O test_user testing_db
   

   An alternative using SQL:

   CREATE DATABASE testing_db OWNER test_user;
   

3. Initialize database

   psql -f sql/schema.sql testing_db
   

   This step can be repeated and clears the database as it drops and recreates the schema testing which is used within the database.

4. Grant privileges to new user

   GRANT ALL PRIVILEGES ON SCHEMA testing TO test_user;
   GRANT ALL PRIVILEGES ON ALL TABLES IN SCHEMA testing TO test_user;
   GRANT ALL PRIVILEGES ON ALL SEQUENCES IN SCHEMA testing TO test_user;
   

5. Create .env file:

   SERVER_ADDR=127.0.0.1:8080
   PG.USER=test_user
   PG.PASSWORD=testing
   PG.HOST=127.0.0.1
   PG.PORT=5432
   PG.DBNAME=testing_db
   PG.POOL.MAX_SIZE=16
   

6. Run the server:

   cargo run
   

7. Using a different terminal send an HTTP POST request to the running server:

   echo '{"email": "ferris@thecrab.com", "first_name": "ferris", "last_name": "crab", "username": "ferreal"}' | http -f --json --print h POST http://127.0.0.1:8080/users
   

   ...or using curl...

   curl -i -d '{"email": "ferris@thecrab.com", "first_name": "ferris", "last_name": "crab", "username": "ferreal"}' -H 'Content-Type: application/json' http://127.0.0.1:8080/users
   

   A unique constraint exists for username, so sending this request twice will return an internal server error (HTTP 500).