Alarms and Logs

A "syslog event" is an entry written to a device's system log. You can subscribe to receive data for syslog events from a device as they occur using the api/space/device-management/devices/get-syslog-events API, and unsubscribe using the api/space/device-management/devices/stop-syslog-events API.

get-syslog-events relies on a HornetQ queue to make a long-running request to subscribe to syslog events on a specified device. This page provides code examples showing how to use these APIs.

Code Examples

The following code examples show how to use the two syslog Device Management APIs to receive and stop receiving syslog events from a device. The examples illustrate a typical sequence of use of the APIs in an application:

Create a queue
Subscribe for syslog events
Poll the queue
Parse the result
Unsubscribe for syslog events

Creating a Queue


String mediatype = "application/hornetq.jms.queue+xml";
Credentials credentials = new UsernamePasswordCredentials("uname", "password");
HttpClient httpClient = new HttpClient();
httpClient.getState().setCredentials(AuthScope.ANY, credentials);
httpClient.getParams().setAuthenticationPreemptive(true);
ClientExecutor clientExecutor = new ApacheHttpClientExecutor(httpClient);
ClientRequest request = new ClientRequest(request_URL, clientExecutor);
String queueString = "<queue name=\"space\"><durable>true</durable></queue>";
request.body(mediatype, queueString);
ClientResponse<String> response = request.post(String.class);
int status = response.getStatus();
if (status == 201) // OK!
{
   System.out.println("QUEUE created : " + response.getHeaders().get("Location"));
else {
   System.out.println("QUEUE creation FAILED : ");
}

Subscribing for Syslog Events


Credentials credentials = new UsernamePasswordCredentials("uname", "password");
HttpClient httpClient = new HttpClient();
httpClient.getState().setCredentials(AuthScope.ANY, credentials);
httpClient.getParams().setAuthenticationPreemptive(true);
ClientExecutor clientExecutor = new ApacheHttpClientExecutor(httpClient);

// request_URL will point to /api/space/device-management/devices/stop-syslog-events/{id} , where id should be valid SyslogTask Id
String request_URL = "http://<<Server_IP>>/api/space/device-management/devices/get-syslog-events?queue=http://<<Server_IP>>/api/hornet-q/queues/jms.queue.space";
String mediatype = "application/vnd.net.juniper.space.device-management.get-syslog-events+xml;version=1;charset=UTF-8";
ClientRequest request = new ClientRequest(request_URL, clientExecutor);
request.header("Content-Type", mediatype);
String input = "<get-syslog-events><devices><device>/api/space/device-management/devices/12345</device></devices><text-patterns><text-pattern>netconf subsystem</text-pattern></text-patterns></get-syslog-events>";
request.body(mediatype, input);
ClientResponse<SyslogTask> response = request.post(SyslogTask.class);
int status = response.getStatus();
System.out.println(" Status=" + status);
if (status == 200) // OK!
{
    System.out.println("SyslogTask ID : " + response.getEntity().getId());
} else {
    System.out.println("get-syslog-events failed......");
}

Polling the Queue


ClientRequest request = new ClientRequest(request_URL);
ClientResponse res = request.get();
String pullConsumers = (String) ((ArrayList) res.getHeaders().get("msg-pull-consumers")).get(0);
request = new ClientRequest(pullConsumers);
res = request.post();
String ackNext = (String) ((ArrayList) res.getHeaders().get("msg-consume-next")).get(0);
while (true)
{
   request = new ClientRequest(ackNext);
   res = request.header("Accept-Wait", "10").post();
   if (res.getStatus() == 503) {
      ackNext = (String) ((ArrayList) res.getHeaders().get("msg-consume-next")).get(0);
   } else if (res.getStatus() == 200) {
      String result = (String) res.getEntity(String.class);
      if(result.contains("<data>")
      {
         // Parse the data tag. Can use XPath
         break;
      }
      ackNext = (String) ((ArrayList) res.getHeaders().get("msg-consume-next")).get(0);
   } else {
      throw new RuntimeException("Failure! " + res.getStatus());
   }
}

Parsing Syslog Events

Parse the asynchronous syslog messages received from the subscribed device by matching text-patterns. The following is an example of a received message.


 <?xml version="1.0" encoding="UTF-8" standalone="yes"?> 
 <progress-update xsi:type="percentage-complete" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> 
   <taskId>100</taskId> 
   <state>INPROGRESS</state> 
   <data> 
      <DeviceSysLog> 
         <deviceID>1234</deviceID> 
         <sysLog>lt;38&gt;1 2010-12-08T11:01:28.849-08:00 blennies sshd 93873 - - subsystem request for netconf</sysLog> 
      </DeviceSysLog> 
   </data> 
</progress-update>

Your code can parse the <data> tag to get the syslog entries.

Unsubscribing for Syslog Events

Unsubscribe for syslog events using the stop-syslog-events API, as shown below.