HTTP probe

HTTP probe allows you to specify a URL that the experiment uses to determine the health or service availability (or other custom conditions) that is a part of the entry or exit criteria. The status code received is mapped against an expected status. It supports HTTP GET and POST methods.

The HTTP GET method sends a GET request to the specified URL. The response code received is matched with the response code based on the given criteria (==, !=, oneOf).

HTTP POST method sends a POST request to the provided URL.

YAML only feature

In the case of a complex POST request in which the body spans multiple lines, the bodyPath attribute is used to specify the path to a file consisting of the same. This file is available to the experiment pod through a ConfigMap resource, wherein the ConfigMap name is defined in the chaos engine or the chaos experiment CR. The body and bodyPath attributes are mutually exclusive. Go to probe schema to learn more.

Defining the probe

You can define the probes at .spec.experiments[].spec.probe path inside the chaos engine.

kind: Workflow
apiVersion: argoproj.io/v1alpha1
spec:
  templates:
    - inputs:
        artifacts:
          - raw:
              data: |
                apiVersion: litmuschaos.io/v1alpha1
                kind: ChaosEngine
                spec:
                  experiments:
                    - spec:
                        probe:
                          ####################################
                          Probes are defined here
                          ####################################

Schema

Listed below is the probe schema for HTTP Probe with common properties shared across all probes and properties unique to HTTP probe.

Field	Description	Type	Range	Notes
name	Flag to hold the name of the probe	Mandatory	N/A type: string	The name holds the name of the probe. It can be set based on the usecase
type	Flag to hold the type of the probe	Mandatory	httpProbe, k8sProbe, cmdProbe, promProbe	The type supports four types of probes. It can one of the httpProbe, k8sProbe, cmdProbe, promProbe
mode	Flag to hold the mode of the probe	Mandatory	SOT, EOT, Edge, Continuous, OnChaos	The mode supports five modes of probes. It can one of the SOT, EOT, Edge, Continuous, OnChaos
url	Flag to hold the URL for the httpProbe	Mandatory	N/A type: string	The url contains the URL which the experiment uses to gauge health/service availability (or other custom conditions) as part of the entry/exit criteria.
insecureSkipVerify	Flag to hold the flag to skip certificate checks for the httpProbe	Optional	true, false	The insecureSkipVerify contains flag to skip certificate checks.
responseTimeout	Flag to hold the flag to response timeout for the httpProbe	Optional	N/A type: integer	The responseTimeout contains flag to provide the response timeout for the http Get/Post request.

Method

GET method properties

Field	Description	Type	Range	Notes
criteria	Flag to hold the criteria for the http get request	Mandatory	==, !=, oneOf	The criteria contains criteria to match the http get request's response code with the expected responseCode, which need to be fulfill as part of httpProbe run
responseCode	Flag to hold the expected response code for the get request	Mandatory	HTTP_RESPONSE_CODE	The responseCode contains the expected response code for the http get request as part of httpProbe run

POST method properties

Field	Description	Type	Range	Notes
criteria	Flag to hold the criteria for the http post request	Mandatory	==, !=, oneOf	The criteria contains criteria to match the http post request's response code with the expected responseCode, which need to be fulfill as part of httpProbe run
responseCode	Flag to hold the expected response code for the post request	Mandatory	HTTP_RESPONSE_CODE	The responseCode contains the expected response code for the http post request as part of httpProbe run
contentType	Flag to hold the content type of the post request	Mandatory	N/A type: string	The contentType contains the content type of the http body data, which need to be passed for the http post request
body	Flag to hold the body of the http post request	Mandatory	N/A type: string	The body contains the http body, which is required for the http post request. It is used for the simple http body. If the http body is complex then use bodyPath field.
bodyPath	Flag to hold the path of the http body, required for the http post request	Optional	N/A type: string	The bodyPath This field is used in case of complex POST request in which the body spans multiple lines, the bodyPath attribute can be used to provide the path to a file consisting of the same. This file can be made available to the experiment pod via a ConfigMap resource, with the ConfigMap name being defined in the ChaosEngine OR the ChaosExperiment CR.

Run properties

Field	Description	Type	Range	Notes
probeTimeout	Flag to hold the timeout of the probe	Mandatory	N/A type: integer	The probeTimeout represents the time limit for the probe to execute the specified check and return the expected data
retry	Flag to hold the retry count of the probe	Mandatory	N/A type: integer	The retry contains the number of times a check is re-run upon failure in the first attempt before declaring the probe status as failed.
interval	Flag to hold the interval of the probe	Mandatory	N/A type: integer	The interval contains the interval for which probes waits between subsequent retries
probePollingInterval	Flag to hold the polling interval for the probes (applicable for all modes)	Optional	N/A type: integer	The probePollingInterval contains the time interval for which continuous probe should be sleep after each iteration
initialDelaySeconds	Flag to hold the initial delay interval for the probes	Optional	N/A type: integer	The initialDelaySeconds represents the initial waiting time interval for the probes.
stopOnFailure	Flags to hold the stop or continue the experiment on probe failure	Optional	N/A type: boolean	The stopOnFailure can be set to true/false to stop or continue the experiment execution after probe fails

Definition

probe:
  - name: "check-frontend-access-url"
    type: "httpProbe"
    httpProbe/inputs:
      url: "<url>"
      insecureSkipVerify: false
      responseTimeout: <value> # in milli seconds
      method:
        get:
          criteria: == # supports == & != and oneof operations
          responseCode: "<response code>"
    mode: "Continuous"
    runProperties:
      probeTimeout: 5
      interval: 5
      retry: 1
      probePollingInterval: 2