# ECS Bridge Plugin

## Overview

The ECS Bridge plugin configures the network namespace of the container to be
able to communicate with the credentials endpoint of the [ECS Agent](https://github.com/aws/amazon-ecs-agent) by creating a
bridge (if required) and veth pair to connect the container's network namespace
to the bridge. An example configuration for invoking this plugin is listed next:
```json
{
    "type":"ecs-bridge",
    "cniVersion":"0.3.0",
    "bridge":"ecs-br0",
    "mtu":1500,
    "ipam":{
	"type":"ecs-ipam",
	"id":"test",
	"cniVersion":"0.3.0",
	"ipv4-subnet":"169.254.172.0/22",
	"ipv4-routes":[
	    {
		"dst":"169.254.172.1"
	    }
	]
    }
}
```

## Parameters
* `bridge` (string, required): the name of the bridge
* `ipam` (ipam config, required): the ipam configuration to use, refer 
to ../ipam/README.md for more details 
* `mtu` (int, optional): the maximum transmission unit size for the bridge

## Example
Please ensure that the environment variables needed for running any CNI plugins
are appropriately configured:
* `CNI_COMMAND`: Command to execute eg: ADD.
* `CNI_PATH`: Plugin binary path eg: `pwd`/bin.
* `CNI_IFNAME`: Interface name inside the container

### Add:
```
export CNI_COMMAND=ADD && cat mynet.conf | ../bin/ecs-bridge
```

### Del:
```
export CNI_COMMAND=DEL && cat mynet.conf | ../bin/ecs-bridge
```

`mynet.conf` is the configuration file for the plugin, it's the same as described
in the overview above.

## Testing

### End-to-end Tests

The end-to-end test suite for this package makes the following assumptions:
1. The `ecs-bridge` and `ecs-ipam` plugin executables have been built
2. The `CNI_PATH` environment variable points to the location of these plugins
3. The test is being executed with `root` user privileges

Since these tests invoke the the ECS Bridge plugin as if an end user such as 
the ECS Agent is invoking it, additional configuration variables can be set to 
prevent the test runner from cleaning up the artifacts generated during the test 
execution for debugging purposes: 
* `ECS_PRESERVE_E2E_TEST_LOGS`: This is set to `false` by default.
Overriding with `true` preserves log files from the plugins
* `ECS_BRIDGE_PRESERVE_IPAM_DB`: This is set to `false` by default. Overriding
with `true` preserves the IPAM database generated by the ECS IPAM plugin

Please refer the [Makefile](../../Makefile) for an example of the command line required to
run end-to-end tests (under the `e2e-test` target).