Docker Compose Public Share

Goal

Publicly share a Docker Compose service with a separate zrok environment and a permanent zrok share URL.

Overview

With zrok, you can publicly share a service that's running in Docker. You need a zrok public share running somewhere that it can reach the service you're sharing. As long as that public share is running and your service is available, anyone with the address can use your service.

Here's a short article with an overview of public sharing with zrok.

Walkthrough Video

How it Works

The Docker Compose project uses your zrok account token to reserve a public subdomain and keep sharing the backend target.

When the project runs it will:

enable a zrok environment unless /mnt/.zrok/environment.json exists in the zrok_env volume
reserve a public subdomain for the service unless /mnt/.zrok/reserved.json exists
start sharing the target specified in the ZROK_TARGET environment variable

Create the Docker Project

Make a folder on your computer to use as a Docker Compose project for your zrok public share with a reserved subdomain and switch to the new directory in your terminal.
Download the reserved public share compose.yml project file into the same directory.
Copy your zrok account's enable token from the zrok web console to your clipboard and paste it in a file named .env in the same folder like this:
.env
```
ZROK_ENABLE_TOKEN="8UL9-48rN0ua"
```
Name the Share

This unique name becomes part of the domain name of the share, e.g. https://my-prod-app.in.zrok.io. A random name is generated if you don't specify one.
.env
```
ZROK_UNIQUE_NAME="my-prod-app"
```
Run the Compose project to start sharing the built-in demo web server. Be sure to --detach so the project runs in the background if you want it to auto-restart when your computer reboots.
```
docker compose up --detach
```
Get the public share URL from the output of the zrok-share service or by peeking in the zrok console where the share will appear in the graph.
```
docker compose logs zrok-share
```
Output
```
zrok-public-share-1  |  https://w6r1vesearkj.in.zrok.io/
```

This concludes the minimum steps to begin sharing the demo web server. Read on to learn how to pivot to sharing any website or web service by leveraging additional zrok backend modes.

Proxy Any Web Server

The simplest way to share your existing HTTP server is to set ZROK_TARGET (e.g. https://example.com) in the environment of the docker compose up command. When you restart the share will auto-configure for that URL.

.env

ZROK_TARGET="http://example.com:8080"

docker compose down && docker compose up

Require Authentication

You can require a password or an OAuth login with certain email addresses.

OAuth Email

You can allow specific email addresse patterns by setting ZROK_OAUTH_PROVIDER to github or google and ZROK_OAUTH_EMAILS. Read more about the OAuth features in this blog post.

.env

ZROK_OAUTH_PROVIDER="github"
ZROK_OAUTH_EMAILS="alice@example.com *@acme.example.com"

Caddy is Powerful

The reserved public share project uses zrok's default backend mode, proxy. Another backend mode, caddy, accepts a path to a Caddyfile as the value of ZROK_TARGET (zrok Caddyfile examples).

Caddy is the most powerful and flexible backend mode in zrok. You must reserve a new public subdomain whenever you switch the backend mode, so using caddy reduces the risk that you'll have to share a new frontend URL with your users.

With Caddy, you can balance the workload for websites or web services or share static sites and files or all of the above at the same time. You can update the Caddyfile and restart the Docker Compose project to start sharing the new configuration with the same reserved public subdomain.

Create a Caddyfile. This example demonstrates proxying two HTTP servers with a weighted round-robin load balancer.

Caddyfile
http:// {
  # zrok requires this bind address template
  bind {{ .ZrokBindAddress }}
  reverse_proxy /* {
    to http://httpbin1:8080 http://httpbin2:8080
    lb_policy weighted_round_robin 3 2
  }
}

Create a file compose.override.yml. This example adds two httpbin containers for load balancing, and mounts the Caddyfile into the container.

compose.override.yml
services:
  httpbin1:
    image: mccutchen/go-httpbin
    expose: 8080
  httpbin2:
    image: mccutchen/go-httpbin
    expose: 8080
  zrok-share:
    volumes:
      - ./Caddyfile:/mnt/.zrok/Caddyfile

Start a new Docker Compose project or delete the existing state volume.
```
docker compose down --volumes
```

If you prefer to keep using the same zrok environment with the new share then delete /mnt/.zrok/reserved.json instead of the entire volume.

Run the project to load the new configuration.
```
docker compose up --detach
```

Note the new reserved share URL from the log.

docker compose logs zrok-share

Output

INFO: zrok public URL: https://88s803f2qvao.in.zrok.io/

Goal​

Overview​

Walkthrough Video​

How it Works​

Create the Docker Project​

Proxy Any Web Server​

Require Authentication​

OAuth Email​

Caddy is Powerful​