https://github.com/npalm/docker-discovery-agent

Discovery agent for docker exposed ports
https://github.com/npalm/docker-discovery-agent

Last synced: 28 days ago
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Discovery agent for docker exposed ports

• Host: GitHub
• URL: https://github.com/npalm/docker-discovery-agent
• Owner: npalm
• License: mit
• Created: 2016-06-10T10:40:16.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2019-09-26T20:37:47.000Z (about 5 years ago)
• Last Synced: 2024-10-04T16:57:57.271Z (about 2 months ago)
• Language: Go
• Homepage: https://040code.github.io/2018/02/14/service-discovery/
• Size: 4.88 KB
• Stars: 10
• Watchers: 3
• Forks: 4
• Open Issues: 3
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
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# Discovery agent for docker exposed ports

A simple in go written agent that exposes a minimal REST api so a container can find the exposed port for a container port. The agent is just a workaround for the problem mentioned in https://github.com/docker/docker/issues/3778

## Usages

Start the agent

```

docker run -p 5555:8080 -v /var/run/docker.sock:/var/run/docker.sock \

  --name docker-discovery-agent npalm/docker-discovery-agent

```

Test the agent

```

export DOCKERHOST=$(ifconfig | grep -E "([0-9]{1,3}\.){3}[0-9]{1,3}" | \

  grep -v 127.0.0.1 | awk '{ print $2 }' | cut -f2 -d: | head -n1)

docker run -it -p 80 --add-host="dockerhost:$(DOCKERHOST)" --rm centos /bin/bash

```

Now you are on the shell of the container. You can look up the exposed port as follow.

```

# find the container id

CONTAINER_ID=$(cat /proc/self/cgroup  | grep "cpu:/" | sed 's/\([0-9]\):cpu:\/docker\///g')

# request the port binding for mapped port 80

curl "http://dockerhost:5555/container/${CONTAINER_ID}/portbinding?port=80&protocol=tcp"

```

The response will look like:

```[{"HostIp":"0.0.0.0","HostPort":"12345"}]```

## REST API

Only a minimal API is implemented

## Health check

Once the service is running the health check should response with a 200 status code.

```resource:  

   response: 200 OK

```

## Port binding

 ```

resource: /container/{id}/portbinding?port={port}&protocol={protocol}

response: A JSON resprenting the exposded port for container with id

          {

            "HostIp": "",

            "HostPort": ""

          }

```