List preemption history of a Google Compute Engine instance

This sample lists all preemption operations that happened in a given zone in a project. Optionally, you can filter the results to only include operations for a specific instance.

Code sample

Go

Before trying this sample, follow the Go setup instructions in the Compute Engine quickstart using client libraries. For more information, see the Compute Engine Go API reference documentation.

To authenticate to Compute Engine, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

import (
	"context"
	"fmt"
	"io"
	"strings"

	compute "cloud.google.com/go/compute/apiv1"
	computepb "cloud.google.com/go/compute/apiv1/computepb"
	"google.golang.org/api/iterator"
	"google.golang.org/protobuf/proto"
)

// preemptionHisory gets a list of preemption operations from given zone in a project.
// Optionally limit the results to instance name.
func preemptionHisory(w io.Writer, projectID, zone, instanceName, customFilter string) error {
	// projectID := "your_project_id"
	// zone := "europe-central2-b"
	// instanceName := "your_instance_name"
	// customFilter := "operationType=\"compute.instances.preempted\""

	ctx := context.Background()
	operationsClient, err := compute.NewZoneOperationsRESTClient(ctx)
	if err != nil {
		return fmt.Errorf("NewZoneOperationsRESTClient: %w", err)
	}
	defer operationsClient.Close()

	filter := ""

	if customFilter != "" {
		filter = customFilter
	} else {
		filter = "operationType=\"compute.instances.preempted\""

		if instanceName != "" {
			filter += fmt.Sprintf(
				` AND targetLink="https://www.googleapis.com/compute/v1/projects/%s/zones/%s/instances/%s"`,
				projectID, zone, instanceName,
			)
		}
	}

	req := &computepb.ListZoneOperationsRequest{
		Project: projectID,
		Zone:    zone,
		Filter:  proto.String(filter),
	}

	it := operationsClient.List(ctx, req)
	for {
		operation, err := it.Next()
		if err == iterator.Done {
			break
		}
		if err != nil {
			return err
		}

		ss := strings.Split(operation.GetTargetLink(), "/")
		curInstName := ss[len(ss)-1]
		if curInstName == instanceName {
			// The filter used is not 100% accurate, it's `contains` not `equals`
			// So we need to check the name to make sure it's the one we want.
			fmt.Fprintf(w, "- %s %s\n", instanceName, operation.GetInsertTime())
		}
	}

	return nil
}

Java

Before trying this sample, follow the Java setup instructions in the Compute Engine quickstart using client libraries. For more information, see the Compute Engine Java API reference documentation.

To authenticate to Compute Engine, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

import com.google.cloud.compute.v1.ListZoneOperationsRequest;
import com.google.cloud.compute.v1.Operation;
import com.google.cloud.compute.v1.ZoneOperationsClient;
import com.google.cloud.compute.v1.ZoneOperationsClient.ListPagedResponse;
import java.io.IOException;
import java.time.Instant;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class ListZoneOperations {

  public static void main(String[] args) throws IOException {
    // TODO(developer): Replace these variables before running the sample.
    // projectId: project ID or project number of the Cloud project you want to use.
    // zone: name of the zone you want to use. For example: “us-west3-b”
    // instanceName: name of the virtual machine to look for.
    String projectId = "your-project-id-or-number";
    String zone = "zone-name";
    String instanceName = "instance-name";

    preemptionHistory(projectId, zone, instanceName);
  }


  // List all recent operations that happened in given zone in a project. Optionally filter those
  // operations by providing a filter. More about using the filter can be found here:
  // https://cloud.google.com/compute/docs/reference/rest/v1/zoneOperations/list
  public static ListPagedResponse listZoneOperations(String projectId, String zone, String filter)
      throws IOException {

    try (ZoneOperationsClient zoneOperationsClient = ZoneOperationsClient.create()) {
      ListZoneOperationsRequest request = ListZoneOperationsRequest.newBuilder()
          .setProject(projectId)
          .setZone(zone)
          .setFilter(filter)
          .build();

      return zoneOperationsClient.list(request);
    }
  }


  // Get a list of preemption operations from given zone in a project. Optionally limit
  // the results to instance name.
  private static void preemptionHistory(String projectId, String zone, String instanceName)
      throws IOException {

    String filter;
    String thisInstanceName;
    String targetLink;
    List<List<String>> history = new ArrayList<>();

    if (instanceName != null && instanceName.length() != 0) {
      filter = String.format(
          "operationType=\"compute.instances.preempted\" AND targetLink:instances/%s",
          instanceName);
    } else {
      filter = "operationType=\"compute.instances.preempted\"";
    }

    for (Operation operation : listZoneOperations(projectId, zone, filter).iterateAll()) {
      targetLink = operation.getTargetLink();
      thisInstanceName = targetLink.substring(targetLink.lastIndexOf("/") + 1);

      // The filter used above performs a 'contains' operation instead of 'equals'
      // So, the result (thisInstanceName) might not be tightly coupled with instanceName.
      // Hence, we need to check the name to make sure it's the one we want.
      if (thisInstanceName.equalsIgnoreCase(instanceName)) {
        Instant instant = Instant.from(
            DateTimeFormatter.ISO_INSTANT.parse(operation.getInsertTime()));
        history.add(new ArrayList<>(Arrays.asList(instanceName, instant.toString())));
      }
    }

    System.out.println("Retrieved preemption history: " + history);
  }
}

Node.js

Before trying this sample, follow the Node.js setup instructions in the Compute Engine quickstart using client libraries. For more information, see the Compute Engine Node.js API reference documentation.

To authenticate to Compute Engine, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

/**
 * TODO(developer): Uncomment and replace these variables before running the sample.
 */
// const projectId = 'YOUR_PROJECT_ID';
// const zone = 'europe-central2-b';
// const instanceName = 'YOUR_INSTANCE_NAME';
// const customFilter = 'operationType="compute.instances.preempted"';

const compute = require('@google-cloud/compute');

async function preemptionHistory() {
  const zoneOperationsClient = new compute.ZoneOperationsClient();

  let filter;

  if (customFilter !== '') {
    filter = customFilter;
  } else {
    filter = 'operationType="compute.instances.preempted"';

    if (instanceName !== '') {
      filter += ` AND targetLink="https://www.googleapis.com/compute/v1/projects/${projectId}/zones/${zone}/instances/${instanceName}"`;
    }
  }

  const [operationsList] = await zoneOperationsClient.list({
    project: projectId,
    zone,
    filter,
  });

  for (const operation of operationsList) {
    const thisInstanceName = operation.targetLink.split('/').pop();
    if (thisInstanceName === instanceName) {
      // The filter used is not 100% accurate, it's `contains` not `equals`
      // So we need to check the name to make sure it's the one we want.
      console.log(`- ${instanceName} ${operation.insertTime}`);
    }
  }
}

preemptionHistory();

Python

Before trying this sample, follow the Python setup instructions in the Compute Engine quickstart using client libraries. For more information, see the Compute Engine Python API reference documentation.

To authenticate to Compute Engine, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

from __future__ import annotations

import datetime

from google.cloud import compute_v1
from google.cloud.compute_v1.services.zone_operations import pagers


def list_zone_operations(
    project_id: str, zone: str, filter: str = ""
) -> pagers.ListPager:
    """
    List all recent operations the happened in given zone in a project. Optionally filter those
    operations by providing a filter. More about using the filter can be found here:
    https://cloud.google.com/compute/docs/reference/rest/v1/zoneOperations/list
    Args:
        project_id: project ID or project number of the Cloud project you want to use.
        zone: name of the zone you want to use. For example: "us-west3-b"
        filter: filter string to be used for this listing operation.
    Returns:
        List of preemption operations in given zone.
    """
    operation_client = compute_v1.ZoneOperationsClient()
    request = compute_v1.ListZoneOperationsRequest()
    request.project = project_id
    request.zone = zone
    request.filter = filter

    return operation_client.list(request)


def preemption_history(
    project_id: str, zone: str, instance_name: str = None
) -> list[tuple[str, datetime.datetime]]:
    """
    Get a list of preemption operations from given zone in a project. Optionally limit
    the results to instance name.
    Args:
        project_id: project ID or project number of the Cloud project you want to use.
        zone: name of the zone you want to use. For example: "us-west3-b"
        instance_name: name of the virtual machine to look for.
    Returns:
        List of preemption operations in given zone.
    """
    if instance_name:
        filter = (
            f'operationType="compute.instances.preempted" '
            f"AND targetLink:instances/{instance_name}"
        )
    else:
        filter = 'operationType="compute.instances.preempted"'

    history = []

    for operation in list_zone_operations(project_id, zone, filter):
        this_instance_name = operation.target_link.rsplit("/", maxsplit=1)[1]
        if instance_name and this_instance_name == instance_name:
            # The filter used is not 100% accurate, it's `contains` not `equals`
            # So we need to check the name to make sure it's the one we want.
            moment = datetime.datetime.fromisoformat(operation.insert_time)
            history.append((instance_name, moment))

    return history

What's next

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