Java Code Examples for com.amazonaws.services.ec2.model.DescribeInstancesRequest#setNextToken()

/**
 * Calls DescribeInstances on the AWS EC2 Client returning all instances that match the supplied predicate and attempting
 * to push down certain predicates (namely queries for specific ec2 instance) to EC2.
 *
 * @See TableProvider
 */
@Override
public void readWithConstraint(BlockSpiller spiller, ReadRecordsRequest recordsRequest, QueryStatusChecker queryStatusChecker)
{
    boolean done = false;
    DescribeInstancesRequest request = new DescribeInstancesRequest();

    ValueSet idConstraint = recordsRequest.getConstraints().getSummary().get("instance_id");
    if (idConstraint != null && idConstraint.isSingleValue()) {
        request.setInstanceIds(Collections.singletonList(idConstraint.getSingleValue().toString()));
    }

    while (!done) {
        DescribeInstancesResult response = ec2.describeInstances(request);

        for (Reservation reservation : response.getReservations()) {
            for (Instance instance : reservation.getInstances()) {
                instanceToRow(instance, spiller);
            }
        }

        request.setNextToken(response.getNextToken());

        if (response.getNextToken() == null || !queryStatusChecker.isQueryRunning()) {
            done = true;
        }
    }
}
 

@Override
public List<Instance> getInstancesForZone(AvailabilityZone zone, AmazonEC2Client client)
    throws Exception {
  OperationStats op = new OperationStats("ec2InstanceStore", "getInstancesForZone");
  try {
    List<Instance> ret = new ArrayList<>();
    DescribeInstancesRequest request = new DescribeInstancesRequest()
        .withMaxResults(1000)
        .withFilters(new Filter("availability-zone", Arrays.asList(zone.getZoneName())))
        .withSdkClientExecutionTimeout(
            600 * 1000) //10 minutes time out for total execution including retries
        .withSdkRequestTimeout(300 * 1000); //5 minutes time out for a single request

    List<Reservation> reservations = new ArrayList<>();
    DescribeInstancesResult result = client.describeInstances(request);
    while (result != null) {
      reservations.addAll(result.getReservations());
      if (result.getNextToken() != null) {
        request.setNextToken(result.getNextToken());
        result = client.describeInstances(request);
      } else {
        result = null;
      }
    }

    for (Reservation reservation : reservations) {
      //Reservation refers to one launch command in EC2. Most time it should
      //only contains one instance
      for (Instance inst : reservation.getInstances()) {
        ret.add(inst);
      }
    }
    op.succeed();
    return ret;
  } catch (Exception ex) {
    op.failed();
    throw ex;
  }
}
 

public static void main(String[] args)
{
    final AmazonEC2 ec2 = AmazonEC2ClientBuilder.defaultClient();
    boolean done = false;

    DescribeInstancesRequest request = new DescribeInstancesRequest();
    while(!done) {
        DescribeInstancesResult response = ec2.describeInstances(request);

        for(Reservation reservation : response.getReservations()) {
            for(Instance instance : reservation.getInstances()) {
                System.out.printf(
                    "Found instance with id %s, " +
                    "AMI %s, " +
                    "type %s, " +
                    "state %s " +
                    "and monitoring state %s",
                    instance.getInstanceId(),
                    instance.getImageId(),
                    instance.getInstanceType(),
                    instance.getState().getName(),
                    instance.getMonitoring().getState());
            }
        }

        request.setNextToken(response.getNextToken());

        if(response.getNextToken() == null) {
            done = true;
        }
    }
}
 

private static void describeInstancesBatch(
        final AmazonEC2 ec2, final Map<String, Instance> described, final List<String> batch) {
    // we are going to modify list, so copy
    final List<String> copy = new ArrayList<>(batch);

    // just to simplify debug by having consist order
    Collections.sort(copy);

    // because instances could be terminated at any time we do multiple
    // retry to get status and all time remove from request all non found instances if any
    while (copy.size() > 0) {
        try {
            final DescribeInstancesRequest request = new DescribeInstancesRequest().withInstanceIds(copy);

            DescribeInstancesResult result;
            do {
                result = ec2.describeInstances(request);
                request.setNextToken(result.getNextToken());

                for (final Reservation r : result.getReservations()) {
                    for (final Instance instance : r.getInstances()) {
                        // if instance not in terminated state, add it to described
                        if (!TERMINATED_STATES.contains(instance.getState().getName())) {
                            described.put(instance.getInstanceId(), instance);
                        }
                    }
                }
            } while (result.getNextToken() != null);

            // all good, clear request batch to stop
            copy.clear();
        } catch (final AmazonEC2Exception exception) {
            // if we cannot find instance, that's fine assume them as terminated
            // remove from request and try again
            if (exception.getErrorCode().equals(NOT_FOUND_ERROR_CODE)) {
                final List<String> notFoundInstanceIds = parseInstanceIdsFromNotFoundException(exception.getMessage());
                if (notFoundInstanceIds.isEmpty()) {
                    // looks like we cannot parse correctly, rethrow
                    throw exception;
                }
                copy.removeAll(notFoundInstanceIds);
            }
        }
    }
}