Web Transactions

Commercial

This ZenPack is developed and supported by Zenoss Inc. Commercial ZenPacks are available to Zenoss commercial customers only. Contact Zenoss to request more information regarding this or any other ZenPacks. Click here to view all available Zenoss Commercial ZenPacks.

Organization:

Zenoss, Inc.

Name:

ZenPacks.zenoss.PS.WebTransaction

ZenPacks.zenoss.PS.WebTransaction

Contents

• About
• Prerequisites
• Usage:
  • Datasource Recipes:
  • Web Transaction Success Validation:
  • Custom Recipe:
    • Examples
  • Troubleshooting / Debugging Transactions:
• Selenium Grid Transaction Execution:
• Changelog

About

A Web Transaction is an interaction, of one or multiple steps, between a web browser & server. A web transaction example could be the submission of authentication credentials and validating the expected page shows after login.

Releases:

1.0.1 - Automated build fixes [SVC-3399]

1.0.0 - Initial Release

• SVC-3360 Datasource UI enhancements
• SVC-3218 Datasource UI
• SVC-3152 Build testing/polling infrastructure & framework

What this ZenPack delivers:

1. Use an actual Web Browser to perform Web Transactions
2. Perform simple static, scripted transaction testing of web applications
3. Perform web transaction testing from a Zenoss Collector or Selenium Grid Instance
4. Web Transaction testing results of:
   1. Metric for time taken to perform the full transaction
   2. Events for failed web page element location and validation of web page element values and/or attribute values

What this ZenPack does not intend to be:

1. Multiple location Web Transaction testing platform
2. Multiple browser Web Transaction testing platform
3. A complex Web Transaction tester
4. An extractor of values from web pages to Datapoints

Prerequisites

The table lists the Zenpack dependencies.

Prerequisite	Restriction
Product	Zenoss 6.2.1 or higher
Required ZenPacks	ZenPacks.zenoss.ZenPackLib >= 2.1.2, ZenPacks.zenoss.PythonCollector >= 1.11.0, ZenPacks.zenoss.PS.Util >= 1.11.2
Other dependencies	Selenium Grid, Chromium Web Browser

Installation:

Non-Cloud Zenoss users should be aware that docker images will also need to be installed with the ZenPack. Installation instructions and files should be provided with the ZenPack.

Usage:

The goal of this ZenPack is to provide a method to perform a known, defined test against web applications in order validate and monitor health and performance. Using the concept of a recipe to encapsulate a defined Web Transaction test for easy re-use. These recipes are selectable and configured from the "Web Transaction" datasource.

This ZenPack delivers Web Transaction monitoring using Selenium Grid. "Selenium Grid allows the execution of WebDriver scripts on remote machines by routing commands sent by the client to remote browser instances" [https://www.selenium.dev/documentation/grid/]. By using Selenium, Web Transactions are run through an actual Web Browser. This ZenPack currently makes exclusive use of the Chromium browser.

Datasource Recipes:

• HTTP - Get - Perform a simple HTTP Get request and optional content verification.
• Login - Basic Auth - Perform a simple Basic Auth test and optional content verification.
• Login - Form - Perform authentication by submitting login credentials via a web form. This is achieved by providing the form elements locator information and data to submit, in the recipe configuration.
• Custom - Not a specific recipe, allows you use python and Web Transaction methods to define a customized Web Transaction test.

Web Transaction Success Validation:

To validate the success of a Web Transaction, use the Datasource Recipe verify fields. All Web Transaction Recipes have the same four verification fields: "Verify Element", "Verify Text Value", "Verify Element Attribute", "Verify Element Attr Value". An element is a part of a web page, which can be seen by looking at the web page source. The verify Element value can be a HTML tag name, tag 'id' attribute value, HTML DOM XPath, or tag class value. If content validation is desired, the "Verify Element" will be a required field while the remaining verify fields are not all required.

Web Transaction recipes that interact with an element (e.g. filling an input box, clicking) follow the same logic as "Verify Element".

Recipe fields that define a "Value" to be verified, can also use zProperty or cProperty fields (e.g. ${here/cWebTransactionPassword}). This is especially useful for password type values or re-use of monitoring templates by not hardcoding values into the template.

NOTE: Transaction validation does not include SSL certificate validation. All certificate errors are ignored.

Custom Recipe:

When there is not a Recipe that fits the testing need, there is the "Custom" Recipe option. A Custom recipe is basically using the special methods in a python script. These methods are special in that they combine and/or enhance the basic capability provided by the selenium-python driver.

Before any Custom Recipe script is performed, the maximum wait time for a web page to load is set to the "zPageLoadTimeout" value and a driver.get() is performed on the URL defined in the datasource configuration. The defined custom recipe actions are then performed.

ZenPack provided methods:

• findElement - Find the first matching element in the HTML DOM. Search by tag name, tag 'id' attribute value, XPath, tag class. Timeout to find element, defined in the "zFindElementTimeout" property (default value is 10). Elements can be interacted with in a number of ways; click(), send_keys(), etc. (Reference: https://www.selenium.dev/documentation/webdriver/elements/interactions/)
• verifyElement - uses "findElement" and then verifies one or both of element's text or attribute value. Some element values do change dynamically after initial page load and this method will wait to match desired result. Timeout to match element's value is defined in the "zVerifyElementValueTimeout" property (default is 10 seconds).
• clickElement - uses "findElement" and then waits until the element is clickable. The click wait re-uses the timeout defined in the "zFindElementTimeout" property.

Exposed Selenium-python Objects/Methods:

• driver - selenium web driver. The above methods should provide all the functionality required for a Web Transaction test. But if they do not, the selenium-python webdriver is exposed here. Usage and its methods are outside the scope of this document but can be found at https://selenium-python.readthedocs.io/getting-started.html.

NOTE: XPath, also known as XML Path, is one of the most commonly used locators in Selenium WebDriver that can help you navigate through the HTML structure of a page. It can be used for HTML and XML documents to locate any element in a web page using HTML DOM structure. How to use or define an XPath to locate an element is beyond the scope of this document.

Examples

The examples provided are more snippets to highlight the use of the Web Transaction methods in a Custom Recipe. They should not be seen as best-practice examples.

Web Login Form Example

This example is what the "Login - Form" recipe would be as a Custom Recipe.

findElement('username').send_keys('${here/cWebTransactionUser}')
findElement('passwrd').send_keys('${here/cWebTransactionPassword}')
clickElement('loginButton')
verifyElement('TITLE', verifyText='Logged In')

"username", "passwrd", & "loginButton" are the 'id' attribute values for HTML "INPUT" tags. Refer to the "findElement" info above for more info on what is used to locate web page elements.

"TITLE" is the HTML tag to be found and then verify that its text value is 'Logged In'. The "verifyElement" method can take up to four parameters; ElementToFind, verifyText, verifyAttr, and verifyAttrVal. The verify parameters are optional but at least one needs to be defined.

# Verify the Element's Text value:
# e.g. <TITLE>Logged In</TITLE>
verifyElement('TITLE', verifyText='Logged In')

# Verify an Element's attribute value
# e.g. <DIV id="header" description="Tuna Harvest Table">Charlie Tuna</DIV>
verifyElement('DIV', verifyAttr='description', verifyAttrVal='Tuna Harvest Table')

# Very both the Element's Text & Attribute value
# e.g. <TABLE><TR id="firstRow"><TD id="exTarget" descr="Apples">Applesauce</TD>.....
verifyElement('exTarget', verifyText='Applesauce', verifyAttr='descr', verifyAttrVal='Apples')

Conditional action/verify Example

nfStatus = findElement('//div[@class="down-notification-content"]/h2')
if nfStatus.get_attribute('textContent') == 'Service is up!':
  findElement('//a[text()="sign in"]').click()
  verifyElement('//h1[@data-uia="login-page-title"]', verifyText='Sign In')

Multi-Step Transaction Example

findElement("username").send_keys("${here/cWebTransactionUser}")
findElement("passwrd").send_keys("${here/cWebTransactionPassword}")
findElement("loginButton").click()
verifyElement("TITLE", verifyText="\n Zenoss:\n Dashboard\n        ")
findElement("Infrastructure-nav-button").click()
verifyElement("device_panel_header-inputEl", "/Devices")
findElement("sign-out-link").click()
verifyElement("TITLE", verifyText="Login")

A multi-step transaction script could be considered as a 'complex' test, which this ZenPack does not aspire to deliver or support. This example is more of an interesting case to test and push the limits of what is possible.

Troubleshooting / Debugging Transactions:

The best method for debugging Web Transaction scripts or recipes is to spin up a dedicated debug Selenium Grid instance. Then set its address in the datasource's "Command Executor" configuration parameter or as the device's "zSeleniumGridCmdExecutor" property. Using a dedicated Selenium Grid instance allows for a variety of different debug options, e.g. connecting to the Node's VNC port and watching the Web Transaction play out in the browser. For more information, reference Selenium's website.

Selenium Grid Transaction Execution:

This ZenPack bundles a Selenium Grid & Chromium Node services that run at the collector level. Web Transactions can also be run from external Selenium Grid instances using the "zSeleniumGridCmdExecutor" zProperty. Its default value being the Zenoss Collector Selenium Grid address.

The "SeleniumGridNodeChrome" service is configured via its service environmental variables. To modify, use the command line of serviced service edit SeleniumGridNodeChrome and update the "Environment" section. Zenoss Selenium Node's default values are:

"Environment": [         "SE_EVENT_BUS_HOST=127.0.0.1",         "SE_EVENT_BUS_PUBLISH_PORT=4442",         "SE_EVENT_BUS_SUBSCRIBE_PORT=4443",         "SE_START_XVFB=false",         "SE_NODE_HOST=nc{{ plus 1 .InstanceID }}",
    "JAVA_OPTS=-Dwebdriver.chrome.whitelistedIps=",
    "SE_NODE_MAX_SESSIONS=2",
    "SE_NODE_SESSION_TIMEOUT=30"
],

Note: You should not change the first 6 options.

Option details:

"JAVA_OPTS=-Dwebdriver.chrome.whitelistedIps=" - to prevent container error messages of [SEVERE]: bind() failed: Cannot assign requested address (99)

"SE_NODE_MAX_SESSIONS=2" - maximum transaction sessions that can run concurrently

"SE_NODE_SESSION_TIMEOUT=30" - Maximum time a transaction may run. zProperty timeouts should not be greater than this value. This is the hard limit for how long a Web Transaction test may take to complete.

For more information, reference https://github.com/SeleniumHQ/docker-selenium#configuring-the-containersbleck

Changelog

1.0.1 - Automated build fixes [SVC-3399]

1.0.0 - Initial Release

• SVC-3360 Datasource UI enhancements
• SVC-3218 Datasource UI
• SVC-3152 Build testing/polling infrastructure & framework