Feature Request: Provide a "ping" operation

[sopgreg]

Our backend application needs to monitor if Holodeck is running. We are already using the REST backend for submission / reception. Using the REST backend for "ping" purposes would be a convenient way to accomplish this.

Should I open a PR for this? Basically, there are only two changes necessary:

rest-backend-service.xml

<operation name="ping">
   <messageReceiver class="org.holodeckb2b.backend.rest.PingOperation"/>
</operation>

New file org.holodeckb2b.backend.rest.PingOperation:

package org.holodeckb2b.backend.rest;

import org.apache.axis2.context.MessageContext;
import org.apache.axis2.receivers.AbstractMessageReceiver;

public class PingOperation extends AbstractMessageReceiver {

	@Override
	public void invokeBusinessLogic(final MessageContext msgCtx) {
	}
}

This results in a HTTP 202 result, which can be interpreted by our backend:

POST http://localhost:8089/holodeckb2b/restbackend/ping

HTTP/1.1 202 Accepted
Date: Thu, 06 Jan 2022 08:24:58 GMT
Transfer-Encoding: chunked
Connection: Keep-Alive

<Response body is empty>

Response code: 202 (Accepted); Time: 112ms; Content length: 0 bytes

[Sander Fieten]

If you just want to check if the gateway if running you can also execute a GET request for URL path /holodeckb2b. If the gateway is running it will respond with a HTTP 200 and a simple HTML page (which you can simply ignore).

[sopgreg]

This does work, but it does not guarantee that the REST backend extension is also correctly deployed. This would therefore be a useful extension