Documentation forWeb Performance Monitor

Use Image Match in the WPM recordings

You can use the Image Match tool to validate if an image is (or is not) included in a recording. This feature can be used in many ways, including to check that a page loaded correctly. For example, the following figure shows a step that verifies that the SolarWinds Customer Portal website loaded properly by checking for the SolarWinds logo:

Note the following details about using Image Match in the Web Transaction Recorder:

  • This feature works in conjunction with the screen resolution option.
  • Make sure Windows Display settings for "Scale and layout" are set to the default value, 100%.
  • Using Image Match for animated objects is not recommended. During playback, animated objects may be in different phases of animation, so WPM may not be able to find the exact recorded image.
  • This feature is not supported in WPM recordings used in Pingdom.
  • You can use this mode in conjunction with X,Y Capture mode to verify images in specific areas during recordings.
  • Using Image Match for pattern images (that is, images that fill regions by placing copies of a pattern side by side, like tiles) is CPU intensive. Select only small regions or portions of the image to improve playback performance. Click here for details.
  • If you know an image won't appear immediately, add wait time before an Image Match step to support successful playback later. When WPM finds a matching image on a page, the timer stops and the next step begins. Image Match time is measured and added to the overall step duration.
  • Avoid using Image Match for images that contain only text.
  • There is no limit to the number of Image Match actions you can add to a recording but the quantity may impact the size of recordings. Recordings over 1 MB can result in:
    • Slow playback in the WPM Recorder.
    • Saving recordings to the Orion server may fail.
    • Creating transaction monitors may fail.
    • Delayed WPM Player communication with the Orion server.
    • OutofMemory exceptions thrown by the SolarWinds Information Service (SWIS).

The Web Transaction Recorder and the WPM Player handle Image Match outcomes differently.

  • Web Transaction Recorder playback: If a recording that includes Image Match doesn't meet configured requirements during playback (for example, if an expected image does not appear in the time allotted), a message appears and provides two options: Close or Skip and continue. You can either close the message to modify the recording, or continue to the next action.
  • WPM Player playback: If you assign a recording with Image Match to a location to create a transaction the WPM Player run, but it doesn't meet configured requirements, the WPM Player service reports that the transaction failed, and the transaction status appears as Down in the Orion Web Console.

You can enable Image Match while you're recording, as described next, or by clicking Image Match when playing back a recording. You can also edit Image Match settings for a step in an existing recording, or modify the similarity factor.

WPM does not support editing for captured pattern images.

To enable Image Match during recording mode:

  1. Launch the Web Transaction Recorder:
  2. Provide the URL where you want to record steps.
  3. Set the screen resolution.
  4. Click Start Recording.
  5. Click the Image Match icon.

  6. Click and hold the left mouse button while dragging the mouse to select the image to match.
  7. Release the mouse button. A new step appears in the Recorded Steps pane. By default, WPM will verify that the image is on the page."
  8. (Optional) Click the Options () icon on the new step and select Edit to:
    • Specify that the image should not appear on the page, or
    • Add a wait time for Image Match.

Modify the similarity factor for Image Match

You can adjust the similarity factor for each system that hosts a Web Transaction Recorder or WPM Player, which determines how close a real-time image must match the image that was originally captured in a recording. To do so, adjust the image_match_similarity_factor value in the config-yaml file, which can vary from .99 to the lowest recommended minimum, .09. The higher the value, the closer the match must be for success.

You cannot edit the similarity factor for individual recordings — only for machines running WPM.

Two config.yaml files are typically stored in the following folders:

  • Web Transaction Recorder: C:\Program Files (x86)\SolarWinds\Orion\SEUM\Recorder\ChromiumProbe\
  • WPM Player: C:\Program Files (x86)\SolarWinds\Orion\SEUM\Player\ChromiumProbe\

If no config.yaml file exists in these locations, use these default values to create it:

"image_match_similarity_factor": 0.99,
"image_match_scroll_x_interval": 100,
"image_match_scroll_y_interval": 100,

To determine the current similar factor settings in a config.yaml file, increase the logging level to VERBOSE in the Orion Log Adjuster. For the WPM Recorder, look for the "Recorder" logger in Log Adjuster. For the WPM Player, look for "Agent Worker - Player". Click here for details.

Here is an example of a WPM Player log with Image Match similarity factor information:

[PROBE|wpm_recorder] Using settings: { 'find_element_timeout': '5.0,',
'find_element_retry_interval': '0.5,',
'image_match_similarity_factor': '0.99,',
'image_match_scroll_x_interval': '100,',
'image_match_scroll_y_interval': '100,',}