hello-docker-compose

Dapr with Docker-Compose

Sample info

Attribute	Details
Dapr runtime version	v0.9
Language	Javascript, Python
Environment	Local

Overview

This sample demonstrates how to get Dapr running locally with Docker Compose. This uses the same applications as the hello-world quickstart, please review that quickstart for further information on the application architecture.

Prerequisites

Clone this repo using git clone https://github.com/dapr/samples.git and go to the directory named /hello-docker-compose

• Docker
• Docker Compose

Reviewing the Docker Compose Definition

Review the Docker Compose file ./docker-compose.yml below:

version: '3'
services:
  ############################
  # Node app + Dapr sidecar
  ############################
  nodeapp:
    build: ./node
    ports:
      - "50002:50002"
    depends_on:
      - redis
      - placement
    networks:
      - hello-dapr
  nodeapp-dapr:
    image: "daprio/daprd:edge"
    command: ["./daprd",
     "-app-id", "nodeapp",
     "-app-port", "3000",
     "-placement-host-address", "placement:50006",
     "-dapr-grpc-port", "50002",
     "-components-path", "/components"]
    volumes:
        - "./components/:/components"
    depends_on:
      - nodeapp
    network_mode: "service:nodeapp"
  ############################
  # Python app + Dapr sidecar
  ############################
  pythonapp:
    build: ./python
    depends_on:
      - redis
      - placement
    networks:
      - hello-dapr
  pythonapp-dapr:
    image: "daprio/daprd:edge"
    command: ["./daprd",
    "-app-id", "pythonapp",
    "-placement-host-address", "placement:50006",
    "-components-path", "/components"]
    volumes:
      - "./components/:/components"
    depends_on:
      - pythonapp
    network_mode: "service:pythonapp"
  ############################
  # Dapr placement service
  ############################
  placement:
    image: "daprio/dapr"
    command: ["./placement", "-port", "50006"]
    ports:
      - "50006:50006"
    networks:
      - hello-dapr
  ############################
  # Redis state store
  ############################
  redis:
    image: "redis:alpine"
    ports:
      - "6380:6379"
    networks:
      - hello-dapr
networks:
    hello-dapr:

Services

This Docker Compose defintion has the following containerized services:

• nodeapp // The node app
• nodeapp-dapr // The node app Dapr sidecar
• pythonapp // The python app
• pythonapp-dapr // The python app Dapr sidecar
• placement // Dapr's placement service
• redis // Redis

Networking

Each of these services is deployed to the hello-dapr Docker network and have their own IP on that network. The nodeapp-dapr and pythonapp-dapr services are sharing a network namespace with their associated app service by using network_mode. This means that the app and the sidecars are able to communicate over their localhost interface.

Ports are still bound on the host machine, therefore, we need to ensure we avoid port conflicts.

Volumes

In order to get Dapr to load the redis statestore and pubsub components, you need to mount the ./components directory to the default working directory. These component definitions have been modified to talk to redis using a DNS name redis rather than localhost. This resolves on the Docker network to the IP of the container running redis.

Deploy the Docker Compose Definition

To deploy the above docker-compose.yml you can run:

make run

If you want to change the Dapr Docker image used in the deployment, you can set the env var DAPR_IMAGE and run make run. This generates a docker-compose.override.yml file using your custom image. If you want to revert to the default Dapr Docker image, you'll need to remove this file.

altentiavely, you can just use Docker Compose directly:

docker-compose up

For the successful run, logs from nodeapp should appear in order as follows:

nodeapp_1         | Got a new order! Order ID: 1
nodeapp_1         | Successfully persisted state.
nodeapp_1         | Got a new order! Order ID: 2
nodeapp_1         | Successfully persisted state.
nodeapp_1         | Got a new order! Order ID: 3

Clean up

To tear down the Docker Compose deployment, you can run:

docker-compose down

Additional Resources:

Overview of Docker Compose