<%NUMBERING1%>.<%NUMBERING2%>.<%NUMBERING3%> PRTG Manual: WMI Custom String Sensor
The WMI Custom String sensor performs a custom string query via Windows Management Instrumentation (WMI).
- It shows the retrieved string value in the sensor message.
- It also shows the response time.
Your Windows Management Instrumentation Query Language (WQL) query code must be stored in a file on the system of the probe the sensor is created on. If used on a remote probe, the file must be stored on the system running the remote probe. In a cluster setup, please copy the file to every cluster node. Save the file with the query into the \Custom Sensors\WMI WQL scripts subfolder of your PRTG installation. See the section Data Storage for more information about how to find this path.
If your WQL query returns integers or floats, use the WMI Custom Sensor to not only show the returned value in the sensor message, but also monitor the value in a sensor channel.
WMI Custom String Sensor
Click here to enlarge: http://media.paessler.com/prtg-screenshots/wmi_custom_string.png
Remarks
You cannot add this sensor type to cloud probes in PRTG in the cloud. If you want to use this sensor type, please add it to a remote probe device.
Add Sensor
The Add Sensor dialog appears when you manually add a new sensor to a device. It only shows the setting fields that are required for creating the sensor. Therefore, you will not see all setting fields in this dialog. You can change (nearly) all settings in the sensor's Settings tab later.
The following settings for this sensor differ in the Add Sensor dialog in comparison to the sensor's settings page.
|
WQL File
|
Select a file that will be used for this sensor from the list. The sensor will execute it with every scanning interval.
The list contains WQL scripts from the \Custom Sensors\WMI WQL scripts subfolder of your PRTG installation. Please store your script there. If used on a remote probe, the file must be stored on the system running the remote probe. If used on a cluster probe, you must store the file on all servers running a cluster node! For more information on how to find this path, see section Data Storage.
If your WQL query returns integers or floats, use the WMI Custom Sensor to not only show the returned value in the sensor message, but also monitor the value in a sensor channel.
|
Sensor Settings
On the details page of a sensor, click the Settings tab to change its settings.
Usually, a sensor connects to the IP Address or DNS Name of the parent device where you created this sensor. See the Device Settings for details. For some sensor types, you can define the monitoring target explicitly in the sensor settings. Please see below for details on available settings.
|
Sensor Name
|
Enter a meaningful name to identify the sensor. By default, PRTG shows this name in the device tree, as well as in alarms, logs, notifications, reports, maps, libraries, and tickets.
|
Parent Tags
|
Shows Tags that this sensor inherits from its parent device, group, and probe. This setting is shown for your information only and cannot be changed here.
|
Tags
|
Enter one or more Tags, separated by spaces or commas. You can use tags to group sensors and use tag–filtered views later on. Tags are not case sensitive. We recommend that you use the default value.
You can add additional tags to the sensor if you like. Other tags are automatically inherited from objects further up in the device tree. These are visible above as Parent Tags.
|
Priority
|
Select a priority for the sensor. This setting determines where the sensor is placed in sensor lists. Top priority is at the top of a list. Choose from one star (low priority) to five stars (top priority).
|
|
Namespace
|
|
WQL File
|
Shows the name of the file that this sensor uses. Once a sensor is created, you cannot change this value. It is shown for reference purposes only. If you need to change this, please add the sensor anew.
If your WQL query returns integers or floats, use the WMI Custom Sensor to not only show the returned value in the sensor message, but also monitor the value in a sensor channel.
|
Placeholder <#PH1>
|
In your WQL script, you can use up to three placeholders that you can assign a value to in this field. Please enter a string for variable <#PH1> or leave the field empty.
|
Placeholder <#PH2>
|
In your WQL script, you can use up to three placeholders that you can assign a value to in this field. Please enter a string for variable <#PH2> or leave the field empty.
|
Placeholder <#PH3>
|
In your WQL script, you can use up to three placeholders that you can assign a value to in this field. Please enter a string for variable <#PH3> or leave the field empty.
|
Unit String
|
Enter a unit for the data that will be received by your script. This is for displaying purposes only. The unit will be displayed in graphs and tables. Please enter a string.
|
If Value Changes
|
Define what this sensor will do when the sensor value changes. You can choose between:
- Ignore changes (default): The sensor takes no action on change.
- Trigger 'change' notification: The sensor sends an internal message indicating that its value has changed. In combination with a Change Trigger, you can use this mechanism to trigger a notification whenever the sensor value changes.
|
Response Must Include
|
Define which string must be part of the data that is received form the WMI object. You can either enter plain text or a Regular Expression. If the data does not include the search pattern, the sensor will be set to an error state. Please enter a string or leave the field empty.
|
Response Must Not Include
|
Define which string must not be part of the data that is received form the WMI object. You can either enter plain text or a Regular Expression. If the data does include the search pattern, the sensor will be set to an error state. Please enter a string or leave the field empty.
|
For Keyword Search Use
|
Define the format of the search expression you entered above.
- Plain Text: Search for the string as plain text. The characters * and ? work here as placeholders, whereas * stands for no or any number of characters and ? stands for exactly one character (as known from Windows search). This behavior cannot be disabled, so the literal search for these characters is not possible with plain text search.
|
Maximum Length of String
|
Define the maximum allowed length of the string that will be received from the WMI object. If it is longer than this value, the sensor will be set to an error status. Please enter an integer value or leave the field empty.
|
Extract Number Using Regular Expression
|
Define if you want to filter out a numeric value from the string received from the WMI object. You can convert this into a float value, in order to use it with channel limits (see Sensor Channels Settings).
- No extraction: Do not extract a float value. Use the result as a string value.
- Extract a numeric value using a regular expression: Use a regular expression to identify a numeric value in the string and convert it to a float value. Define below. See also the example below.
|
Regular Expression
|
This setting is only visible if number extraction is enabled above. Enter a Regular Expression to identify the numeric value you want to extract from the string returned by the WMI object. You can use capturing groups here. Make sure the expression returns numbers only (including decimal and thousands separators). The result will be further refined by the settings below.
|
Index of Capturing Group
|
This setting is only visible if number extraction is enabled above. If your regular expression uses capturing groups, specify which one will be used to capture the number. Please enter an integer value or leave the field empty.
|
Decimal Separator
|
This setting is only visible if number extraction is enabled above. Define which character to use as decimal separator for the number extracted above. Please enter a string or leave the field empty.
|
Thousands Separator
|
This setting is only visible if number extraction is enabled above. Define which character to use as thousands separator for the number extracted above. Please enter a string or leave the field empty.
|
Sensor Result
|
Define what PRTG will do with the sensor results. Choose between:
- Discard sensor result: Do not store the sensor result.
- Write sensor result to disk (Filename: "Result of Sensor [ID].txt"): Store the last result received from the sensor to the Logs (Sensor) directory in the PRTG data folder on the probe system the sensor is running on (on the Master node if in a cluster). File names: Result of Sensor [ID].txt and Result of Sensor [ID].Data.txt. This is for debugging purposes. PRTG overrides these files with each scanning interval.
For more information on how to find the folder used for storage, see section Data Storage.
This option is not available on cloud probes in PRTG in the cloud.
|
|
Primary Channel
|
Overview
|
Graph Type
|
Define how different channels will be shown for this sensor.
- Show channels independently (default): Show an own graph for each channel.
- Stack channels on top of each other: Stack channels on top of each other to create a multi-channel graph. This will generate an easy-to-read graph that visualizes the different components of your total traffic.
This option cannot be used in combination with manual Vertical Axis Scaling (available in the Sensor Channels Settings settings).
|
Stack Unit
|
This setting is only available if stacked graphs are selected above. Choose a unit from the list. All channels with this unit will be stacked on top of each other. By default, you cannot exclude single channels from stacking if they use the selected unit. However, there is an advanced procedure to do so.
|
Inherited Settings
By default, all following settings are inherited from objects higher in the hierarchy and should be changed there, if necessary. Often, best practice is to change them centrally in the Root group's settings. To change a setting only for this object, disable inheritance by clicking the check mark in front of the corresponding setting name. You will then see the options described below.
|
Scanning Interval
|
Select a scanning interval (seconds, minutes, or hours) from the list. The scanning interval determines the time the sensor waits between two scans. You can change the available intervals in the system administration on PRTG on premises installations.
|
If a Sensor Query Fails
|
Define the number of scanning intervals that a sensor has time reach and check a device again in case a sensor query fails. The sensor can try to re-reach and check a device several times, depending on the option you select here, before it will be set to a Down status. This helps you avoid false alarms if the monitored device has only temporary issues. For previous scanning intervals with failed requests, the sensor will show a Warning status. Choose between:
- Set sensor to "down" immediately: The sensor will show an error immediately after the first failed request.
- Set sensor to "warning" for 1 interval, then set to "down" (recommended): After the first failed request, the sensor will show a yellow warning status. If the following request also fails, the sensor will show an error.
- Set sensor to "warning" for 2 intervals, then set to "down": Show an error status only after three continuously failed requests.
- Set sensor to "warning" for 3 intervals, then set to "down": Show an error status only after four continuously failed requests.
- Set sensor to "warning" for 4 intervals, then set to "down": Show an error status only after five continuously failed requests.
- Set sensor to "warning" for 5 intervals, then set to "down": Show an error status only after six continuously failed requests.
Sensors that monitor via Windows Management Instrumentation (WMI) always wait at least one scanning interval until they show an error. It is not possible to set a WMI sensor to "down" immediately, so the first option will not apply to these sensor types. All other options can apply.
If a sensor has defined error limits for channels, it will always show a Down status immediately, so no "wait" option will apply.
If a channel uses lookup values, it will always show a Down status immediately, so no "wait" options will apply.
|
|
Inheritance for schedules, dependencies, and maintenance windows cannot be interrupted. The corresponding settings from the parent objects will always be active. However, you can define additional settings here. They will be active at the same time as the parent objects' settings.
|
Schedule
|
Select a schedule from the list. Schedules can be used to monitor for a certain time span (days, hours) every week. With the period list option it is also possible to pause monitoring for a specific time span. You can create new schedules and edit existing ones in the account settings.
Schedules are generally inherited. New schedules will be added to existing ones, so all schedules are active at the same time.
|
Maintenance Window
|
- Not set (monitor continuously): No maintenance window will be set and monitoring will always be active.
- Set up a one-time maintenance window: Pause monitoring within a maintenance window. You can define a time span for a monitoring pause below and change it even for a currently running maintenance window.
To terminate a current maintenance window before the defined end date, change the time entry in Maintenance Ends field to a date in the past.
|
Maintenance Begins
|
This field is only visible if you enabled the maintenance window above. Use the date time picker to enter the start date and time of the maintenance window.
|
Maintenance Ends
|
This field is only visible if you enabled the maintenance window above. Use the date time picker to enter the end date and time of the maintenance window.
|
Dependency Type
|
Define a dependency type. Dependencies can be used to pause monitoring for an object depending on the status of another. You can choose between:
- Use parent: Pause the current sensor if the device, where it is created on, is in Down status, or is paused by another dependency.
- Select object: Pause the current sensor if the device, where it is created on, is in Down status, or is paused by another dependency. Additionally, pause the current sensor if a specific other object in the device tree is in Down status, or is paused by another dependency. Select below.
- Master object for parent: Make this sensor the master object for its parent device. The sensor will influence the behavior of the device, where it is created on: If the sensor is in Down status, the device will be paused. For example, it is a good idea to make a Ping sensor the master object for its parent device to pause monitoring for all other sensors on the device in case the device cannot even be pinged. Additionally, the sensor will be paused if the parent group of its parent device is in Down status, or if it is paused by another dependency.
Testing your dependencies is easy! Simply choose Simulate Error Status from the context menu of an object that other objects depend on. A few seconds later all dependent objects should be paused. You can check all dependencies in your PRTG installation by selecting Devices | Dependencies from the main menu bar.
|
Dependency
|
This field is only visible if the Select object option is enabled above. Click on the reading-glasses and use the object selector to choose an object on which the current sensor will depend.
|
Dependency Delay (Sec.)
|
Define a time span in seconds for a dependency delay. After the master object for this dependency goes back to Up status, PRTG will start monitoring the depending objects after this extra delayed. This can help to avoid false alarms, for example, after a server restart, by giving systems more time for all services to start up. Please enter an integer value.
This setting is not available if you choose this sensor to Use parent or to be the Master object for parent. In this case, please define delays in the parent Device Settings or in the superior Group Settings.
|
|
User Group Access
|
Define which user group(s) will have access to the object you're editing. A table with user groups and types of access rights is shown: It contains all user groups from your setup. For each user group you can choose from the following access rights:
- Inherited: Use the access rights settings of the parent object.
- None: Users in this group cannot see or edit the object. The object neither shows up in lists nor in the device tree. Exception: If a child object is visible to the user, the object is visible in the device tree, though not accessible.
- Read: Users in this group can see the object and review its monitoring results.
- Write: Users in this group can see the object, review its monitoring results, and edit the object's settings. They cannot edit access rights settings.
- Full: Users in this group can see the object, review its monitoring results, edit the object's settings, and edit access rights settings.
You can create new user groups in the System Administration—User Groups settings. To automatically set all objects further down in the hierarchy to inherit this object's access rights, set a check mark for the Revert children's access rights to inherited option.
For more details on access rights, please see the section User Access Rights.
|
Example: Number Extraction with Regular Expression
If you want to extract a number in the response string using a regular expression, please note that the index for captures in this sensor is based on 1 (not on 0). Furthermore, capturing groups are not created automatically. The example below will illustrate this issue.
Consider the following string as returned by a request for CPU usage:
5 Sec (3.49%), 1 Min (3.555%), 5 Min (3.90%)
Assuming you would like to filter for the number 3.555, i.e., the percentage in the second parentheses. Then enter the following regex in the Regular Expression field:
(\d+\.\d+).*?(\d+\.\d+).*?(\d+\.\d+)
As Index of Capturing Group enter 3. This will extract the desired number 3.555.
The index has to be 3 in this case because the capturing groups here are the following:
- Group 1 contains "3.49%), 1 Min (3.555), 5 Min (3.90"
- Group 2 contains "3.49"
- Group 3 contains "3.555"
- Group 4 contains "3.90"
Please keep in mind this note about index and capturing groups when using number extraction.
It is not possible to match an empty string with the PRTG regex sensor search.
More
My WMI sensors don't work. What can I do?
Knowledge Base: How do I create a WMI Custom Sensor?
Knowledge Base: Why do I have to store SQL sensor queries and custom scripts in files on the probe computer?
Edit Sensor Channels
To change display settings, spike filter, and limits, switch to the sensor's Overview tab and click the gear icon of a specific channel. For detailed information, please see the Sensor Channels Settings section.
Notifications
Click the Notifications tab to change notification triggers. For detailed information, please see the Sensor Notifications Settings section.
Others
For more general information about settings, please see the Object Settings section.
Sensor Settings Overview
For information about sensor settings, please see the following sections: