--- title: Develop your Rust application keywords: rust, local, development, run, description: Learn how to develop your Rust application locally. --- {% include_relative nav.html selected="3" %} ## Prerequisites * You have installed the latest version of [Docker Desktop](../../get-docker.md). * You have completed the walkthroughs in the Docker Desktop [Learning Center](../../desktop/get-started.md) to learn about Docker concepts. * You have a [git client](https://git-scm.com/downloads). The examples in this section use a command-line based git client, but you can use any client. ## Overview In this section, you’ll learn how to use volumes and networking in Docker. You’ll also use Docker to build your images and Docker Compose to make everything a whole lot easier. First, you’ll take a look at running a database in a container and how you can use volumes and networking to persist your data and allow your application to talk with the database. Then you’ll pull everything together into a Compose file which allows you to set up and run a local development environment with one command. ## Run a database in a container Instead of downloading PostgreSQL, installing, configuring, and then running the PostgreSQL database as a service, you can use the Docker Official Image for PostgreSQL and run it in a container. Before you run PostgreSQL in a container, create a volume that Docker can manage to store your persistent data and configuration. Use the named volumes feature that Docker provides instead of using bind mounts. Run the following command to create your volume. ```console $ docker volume create db-data ``` Now create a network that your application and database will use to talk to each other. The network is called a user-defined bridge network and gives you a nice DNS lookup service which you can use when creating your connection string. ```console $ docker network create postgresnet ``` Now you can run PostgreSQL in a container and attach to the volume and network that you created above. Docker pulls the image from Hub and runs it for you locally. In the following command, option `--mount` is for starting the container with a volume. For more information, see [Docker volumes](../../storage/volumes.md). ```console $ docker run --rm -d --mount \ "type=volume,src=db-data,target=/var/lib/postgresql/data" \ -p 5432:5432 \ --network postgresnet \ --name db \ -e POSTGRES_PASSWORD=mysecretpassword \ -e POSTGRES_DB=example \ postgres ``` Now, make sure that your PostgreSQL database is running and that you can connect to it. Connect to the running PostgreSQL database inside the container. ```console $ docker exec -it db psql -U postgres ``` You should see output like the following. ```console psql (15.3 (Debian 15.3-1.pgdg110+1)) Type "help" for help. postgres=# ``` In the previous command, you logged in to the PostgreSQL database by passing the `psql` command to the `db` container. Press ctrl-d to exit the PostgreSQL interactive terminal. ## Get and run the sample application For the sample application, you'll use a variation of the backend from the react-rust-postgres application from [Awesome Compose](https://github.com/docker/awesome-compose/tree/master/react-rust-postgres). 1. Clone the sample application repository using the following command. ``` $ git clone https://github.com/docker/docker-rust-postgres ``` 2. In the cloned repository's directory, run `docker init` to create the necessary Docker files. Refer to the following example to answer the prompts from `docker init`. ```console $ docker init Welcome to the Docker Init CLI! This utility will walk you through creating the following files with sensible defaults for your project: - .dockerignore - Dockerfile - compose.yaml Let's get started! ? What application platform does your project use? Rust ? What version of Rust do you want to use? 1.70.0 ? What port does your server listen on? 8000 ``` 3. In the cloned repository's directory, run `docker build` to build the image. ```console $ docker build -t rust-backend-image . ``` 4. Run `docker run` to run the image as a container on the same network as the database. ```console $ docker run \ --rm -d \ --network postgresnet \ --name docker-develop-rust-container \ -p 3001:8000 \ -e PG_DBNAME=example \ -e PG_HOST=db \ -e PG_USER=postgres \ -e PG_PASSWORD=mysecretpassword \ -e ADDRESS=0.0.0.0:8000\ -e RUST_LOG=debug \ rust-backend-image ``` 5. Curl the application to verify that it connects to the database. ```console $ curl http://localhost:3001/users ``` You should get a response like the following. ``` [{"id":1,"login":"root"}] ``` ## Use Compose to develop locally When you run `docker init`, in addition to a `Dockerfile`, it also creates a `compose.yaml` file. This Compose file is super convenient as you don't have to type all the parameters to pass to the `docker run` command. You can declaratively do that using a Compose file. In the cloned repository's directory, open the `compose.yaml` file in an IDE or text editor. `docker init` handled creating most of the instructions, but you'll need to update it for your unique application. You need to update the following items in the `compose.yaml` file: - Uncomment all of the database instructions. - Add the environment variables under the server service. The following is the updated `compose.yaml` file. ```yaml # Comments are provided throughout this file to help you get started. # If you need more help, visit the Docker compose reference guide at # https://docs.docker.com/compose/compose-file/ # Here the instructions define your application as a service called "server". # This service is built from the Dockerfile in the current directory. # You can add other services your application may depend on here, such as a # database or a cache. For examples, see the Awesome Compose repository: # https://github.com/docker/awesome-compose services: server: build: context: . target: final ports: - 8000:8000 environment: - PG_DBNAME=example - PG_HOST=db - PG_USER=postgres - PG_PASSWORD=mysecretpassword - ADDRESS=0.0.0.0:8000 - RUST_LOG=debug # The commented out section below is an example of how to define a PostgreSQL # database that your application can use. `depends_on` tells Docker Compose to # start the database before your application. The `db-data` volume persists the # database data between container restarts. The `db-password` secret is used # to set the database password. You must create `db/password.txt` and add # a password of your choosing to it before running `docker compose up`. depends_on: db: condition: service_healthy db: image: postgres restart: always user: postgres secrets: - db-password volumes: - db-data:/var/lib/postgresql/data environment: - POSTGRES_DB=example - POSTGRES_PASSWORD_FILE=/run/secrets/db-password expose: - 5432 healthcheck: test: [ "CMD", "pg_isready" ] interval: 10s timeout: 5s retries: 5 volumes: db-data: secrets: db-password: file: db/password.txt ``` Note that the file doesn't specify a network for those 2 services. When you use Compose, it automatically creates a network and connects the services to it. For more information see [Networking in Compose](../../compose/networking.md). Before you run the application using Compose, notice that this Compose file specifies a `password.txt` file to hold the database's password. You must create this file as it's not included in the source repository. In the cloned repository's directory, create a new directory named `db` and inside that directory create a file named `password.txt` that contains the password for the database. Using your favorite IDE or text editor, add the following contents to the `password.txt` file. ``` mysecretpassword ``` If you have any other containers running from the previous sections, [stop](./run-containers.md/#stop-start-and-name-containers) them now. Now, run the following `docker compose up` command to start your application. ```console $ docker compose up --build ``` The command passes the `--build` flag so Docker will compile your image and then start the containers. Now test your API endpoint. Open a new terminal then make a request to the server using the curl commands: ```console $ curl http://localhost:8000/users ``` You should receive the following response: ``` [{"id":1,"login":"root"}] ``` ## Summary In this section, you took a look at setting up your Compose file to run your Rust application and database with a single command. Related information: - [Docker volumes](../../storage/volumes.md) - [Compose overview](../../compose/index.md) ## Next steps In the next section, you'll take a look at how to set up a CI/CD pipeline using GitHub Actions. [Configure CI/CD](configure-ci-cd.md){: .button .primary-btn}