PRTG Manual: File Content Sensor

The File Content sensor checks a text file (for example, logfiles) for certain strings.

The sensor can show the following:

  • Line number of the last match
  • Number of total matches

Additionally, the sensor quotes matching lines in the sensor message field.

File Content Sensor

File Content Sensor

Sensor in Other Languages

  • Dutch: Bestands inhoud
  • French: Contenu du fichier
  • German: Datei-Inhalt
  • Japanese: ファイルの内容
  • Portuguese: Conteúdo de arquivo
  • Russian: Содержимое файла
  • Simplified Chinese: 文件内容
  • Spanish: Contenido de archivo

Remarks

  • This sensor can have a high impact on the performance of your monitoring system. Use it with care. We recommend that you use no more than 50 sensors of this sensor type on each probe.
  • This sensor requires that the LanmanServer service runs on the target computer.
  • This sensor does not support UTF-16 encoded files. In this case, try to use a custom sensor like the EXE/Script sensor or the EXE/Script Advanced sensor.
  • This sensor does not officially support binary files. If you would still like to monitor binary files contrary to our recommendation, choose the option Always transmit the entire file in the sensor settings, section Network Usage.
  • This sensor supports Unix line feeds.
  • This sensor supports the IPv6 protocol.
  • This sensor has a high performance impact.
  • To monitor files on a Linux system, the folder has to be accessible via server message block (SMB).
  • Try using the fully qualified domain name (FQDN) of the target device if the sensor does not get a connection with the IP address.

i_podYou cannot add this sensor to the hosted probe of a PRTG hosted by Paessler instance. If you want to use this sensor, add it to a remote probe device.

Detailed Requirements

Requirement

Description

LanmanServer service

To monitor shares on Windows machines, make sure that the LanmanServer service runs on the target computer.

i_round_blueThe display name of the service is Server.

To enable the service, log in to the respective computer and open the services manager (for example, via services.msc). In the list, find the respective service and set its Start Type to Automatic.

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 do not see all setting fields in this dialog. You can change (nearly) all settings in the sensor's Settings tab later.

Basic Sensor Settings

Click the Settings tab of a sensor to change its settings.

i_round_blueUsually, a sensor connects to the IP Address or DNS Name of the parent device on which you created the sensor. See the device settings for details. For some sensors, you can explicitly define the monitoring target in the sensor settings. See below for details on available settings.

Setting

Description

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 the sensor inherits from its parent device, parent group, and parent probe. This setting is shown for your information only and cannot be changed here.

Tags

Enter one or more tags. Confirm each tag with the Spacebar key, a comma, or the Enter key. You can use tags to group objects and use tag-filtered views later on. Tags are not case-sensitive. Tags are automatically inherited.

i_round_blueIt is not possible to enter tags with a leading plus (+) or minus (-) sign, nor tags with parentheses (()) or angle brackets (<>).

The sensor has the following default tags that are automatically predefined in the sensor's settings when you add the sensor:

  • filesensor

Priority

Select a priority for the sensor. This setting determines the position of the sensor in lists. The highest priority is at the top of a list. Choose from the lowest priority (i_priority_1) to the highest priority (i_priority_5).

Sensor Specific

Setting

Description

File Name

Enter the full path to the file that this sensor monitors. For example, enter C:\Windows\file.txt. to monitor a file on the probe system.

If you use a local path, the sensor looks for the target file only on the probe system, not on the parent device. To monitor a file on the parent device, use the dollar sign ($) like C$\User\johnqpublic\file.txt.

If the file is located on a network device, use the Universal Naming Convention (UNC) path without the server part (only enter share\folder\file.txt). The server part (\\server\) is taken from the parent device settings of this sensor. Enter a valid path and file name.

i_round_redTo provide any Windows shares, the LanmanServer service must run on the target computer.

i_round_redTo monitor any Linux files, the folder with these files has to be accessible via SMB.

i_round_redNote that it might produce high network traffic if you define that PRTG queries an entire file on your network with every scanning interval.

Search String

Define the string that you want to search the logfile for. You can enter a simple string in plain text or a regular expression.

i_round_redThe search string must be case sensitive.

Search Method

Define the method with which you want to provide the search string:

  • Simple string search: Search for a simple string in plain text.

i_round_blueThe characters * and ? work as placeholders. * stands for no number or any number of characters and ? stands for exactly one character (as known from the Windows search). You cannot change this behavior. The literal search for these characters is only possible with a regular expression.

  • Regular expression: Search with a regular expression (regex).

i_round_redThe pattern must be in one line and only the last matching line is returned.

i_round_bluePRTG supports Perl Compatible Regular Expression (PCRE) regex. For more details, see section Regular Expressions.

Network Usage

Define in which way the sensor transmits the target file to PRTG:

  • Only transmit new lines at the end of the file (default): This option improves the performance of the sensor. It sends the whole file to PRTG only with the first scan. With the following sensor scans, the sensor only transmits lines that have been appended since the last scan. All other lines (that already existed in the previous scan) are not sent. The sensor assumes that they are unchanged and still counts them.
    i_betaThis option is in beta status. Do not expect that it works as expected in every usage scenario.
  • Always transmit the entire file: The sensor sends the whole file to PRTG with every sensor scanning interval. If this results in too much traffic on the target system, we recommend that you choose the new lines option.

The sensor can only transmit newly added lines in the following cases:

  • the file is bigger than at the previous scan, and
  • the last line in the file is still at the same place in the file.

i_round_blueThe sensor supports Windows and Linux line endings (CRLF or. LF).

File Encoding

Specify the encoding of the file that this sensor monitors:

  • Windows-1252
  • UTF-8
  • UTF-16

Warning Behavior

Define under which condition the sensor shows the Warning status:

  • Go into warning status when string is not found: The sensor shows the Warning status if there is no match. Otherwise it remains in the Up status.
  • Go into warning status when string is found: The sensor shows the Warning status if there is a match. Otherwise it remains in the Up status.

If Value Changes

Define what the sensor does when the sensor value changes:

  • Ignore changes (default): Take no action on change.
  • Trigger 'change' notification: Send an internal message indicating that the sensor value has changed. In combination with a change trigger, you can use this mechanism to trigger a notification whenever the sensor value changes.

i_round_redThe notification for this sensor is triggered when the value of the channel Last occurrence (line) changes. It is not triggered when the number of Matches changes.

Debug Options

Setting

Description

Sensor Result

Define what PRTG does with the sensor results:

  • Discard sensor result: Do not store the sensor result.
  • Write sensor result to disk (file names: Result of Sensor [ID].*): Store the last result received from the sensor to the \Logs\sensors subfolder of the PRTG data directory on the probe system (master node, if in a cluster). File names: Result of Sensor [ID].* and Result of Sensor [ID].Data.*. This is for debugging purposes. PRTG overwrites these files with each scanning interval.

i_podThis option is not available when the sensor runs on the hosted probe of a PRTG hosted by Paessler instance.

Sensor Display

Setting

Description

Primary Channel

Select a channel from the list to define it as the primary channel. In the device tree, the last value of the primary channel is always displayed below the sensor's name. The available options depend on what channels are available for this sensor.

i_round_blueYou can set a different primary channel later by clicking b_channel_primary below a channel gauge on the sensor's Overview tab.

Graph Type

Define how different channels are shown for this sensor:

  • Show channels independently (default): Show a 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 generates a graph that visualizes the different components of your total traffic.
    i_round_redYou cannot use this option in combination with manual Vertical Axis Scaling (available in the channel settings).

Stack Unit

This setting is only visible if you enable Stack channels on top of each other as Graph Type. Select a unit from the list. All channels with this unit are 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 of the following settings are inherited from objects that are higher in the hierarchy. You should change them centrally in the root group settings if necessary. To change a setting for this object only, click b_inherited_enabled under the corresponding setting name to disable the inheritance. You then see the options described below.

i_square_cyanFor more information, see section Inheritance of Settings.

Scanning Interval

Click b_inherited_enabled to interrupt the inheritance.

Setting

Description

Scanning Interval

Select a scanning interval from the dropdown list. The scanning interval determines the amount of time that the sensor waits between two scans. Choose from:

  • 30 seconds
  • 60 seconds
  • 5 minutes
  • 10 minutes
  • 15 minutes
  • 30 minutes
  • 1 hour
  • 4 hours
  • 6 hours
  • 12 hours
  • 1 day

i_round_blueYou can change the available intervals in the system administration on PRTG on premises installations.

If a Sensor Query Fails

Select the number of scanning intervals that the sensor has time to reach and to check a device again if a sensor query fails. Depending on the option that you select, the sensor can try to reach and to check a device again several times before the sensor shows the Down status. This can avoid false alarms if the monitored device only has temporary issues. For previous scanning intervals with failed requests, the sensor shows the Warning status. Choose from:

  • Set sensor to down immediately: Set the sensor to the Down status immediately after the first request fails.
  • Set sensor to warning for 1 interval, then set to down (recommended): Set the sensor to the Warning status after the first request fails. If the second request also fails, the sensor shows the Down status.
  • Set sensor to warning for 2 intervals, then set to down: Set the sensor to the Down status only after the third request fails.
  • Set sensor to warning for 3 intervals, then set to down: Set the sensor to the Down status only after the fourth request fails.
  • Set sensor to warning for 4 intervals, then set to down: Set the sensor to the Down status only after the fifth request fails.
  • Set sensor to warning for 5 intervals, then set to down: Set the sensor to the Down status only after the sixth request fails.

i_round_blueSensors that monitor via Windows Management Instrumentation (WMI) always wait at least one scanning interval before they show the Down status. It is not possible to immediately set a WMI sensor to the Down status, so the first option does not apply to these sensors. All other options can apply.

i_round_blueIf you define error limits for a sensor's channels, the sensor immediately shows the Down status. None of the interval options apply.

i_round_blueIf a channel uses lookup values, the sensor immediately shows the Down status. None of the interval options apply.

Schedules, Dependencies, and Maintenance Window

i_round_blueYou cannot interrupt the inheritance for schedules, dependencies, and maintenance windows. The corresponding settings from the parent objects are always active. However, you can define additional schedules, dependencies, and maintenance windows. They are active at the same time as the parent objects' settings.

Setting

Description

Schedule

Select a schedule from the list. You can use schedules to monitor during a certain time span (days or hours) every week. Choose from:

  • None
  • Saturdays
  • Sundays
  • Weekdays
  • Weekdays Eight-To-Eight (08:00 - 20:00)
  • Weekdays Nights (17:00 - 09:00)
  • Weekdays Nights (20:00 - 08:00)
  • Weekdays Nine-To-Five (09:00 - 17:00)
  • Weekends

i_square_cyanYou can create schedules, edit schedules, or pause monitoring for a specific time span. For more information, see section Schedules.

Maintenance Window

Select if you want to set up a one-time maintenance window. During a maintenance window, monitoring stops for the selected object and all child objects. They show the Paused status instead. Choose between:

  • Not set (monitor continuously): Do not set up a one-time maintenance window. Monitoring is always active.
  • Set up a one-time maintenance window: Set up a one-time maintenance window and pause monitoring. You can define a time span for a the pause below.

i_round_blueTo terminate an active maintenance window before the defined end date, change the time entry in Maintenance Ends to a date in the past.

Maintenance Begins

This setting is only visible if you enable Set up a one-time maintenance window above. Use the date time picker to enter the start date and time of the one-time maintenance window.

Maintenance Ends

This setting is only visible if you enable Set up a one-time maintenance window above. Use the date time picker to enter the end date and time of the one-time maintenance window.

Dependency Type

Select a dependency type. You can use dependencies to pause monitoring for an object depending on the status of a different object. You can choose from:

  • Use parent: Use the dependency type of the parent object.
  • Select a sensor: Use the dependency type of the parent object. Additionally, pause the current object if a specific sensor is in the Down status or in the Paused status because of another dependency.
  • Master sensor for parent: Make this sensor the master object for its parent device. The sensor influences the behavior of its parent device: If the sensor is in the Down status, the device is 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 is paused if the parent group is paused by another dependency.

i_round_blueTo test your dependencies, select Simulate Error Status from the context menu of an object that other objects depend on. A few seconds later, all dependent objects are paused. You can check all dependencies under Devices | Dependencies in the main menu bar.

Dependency

This setting is only visible if you enable Select a sensor above. Click b_search_light and use the object selector to select a sensor on which the current object will depend.

Dependency Delay (Sec.)

This setting is only visible if you enable Select a sensor above. Define a time span in seconds for the dependency delay.

After the master sensor for this dependency returns to the Up status, PRTG additionally delays the monitoring of the dependent objects by the time span you define. This can prevent false alarms, for example, after a server restart or to give systems more time for all services to start. Enter an integer value.

i_round_redThis setting is not available if you set this sensor to Use parent or to be the Master sensor for parent. In this case, define delays in the parent device settings or in its parent group settings.

Access Rights

Click b_inherited_enabled to interrupt the inheritance.

Setting

Description

User Group Access

Define the user groups that have access to the sensor. You see a table with user groups and group access rights. The table contains all user groups in your setup. For each user group, you can choose from the following group access rights:

  • Inherited: Inherit the access rights settings of the parent object.
  • No access: Users in this user group cannot see or edit the sensor. The sensor neither shows up in lists nor in the device tree.
  • Read access: Users in this group can see the sensor and view its monitoring results. They cannot edit any settings.
  • Write access: Users in this group can see the sensor, view its monitoring results, and edit its settings. They cannot edit its access rights settings.
  • Full access: Users in this group can see the sensor, view its monitoring results, edit its settings, and edit its access rights settings.

i_square_cyanFor more details on access rights, see section Access Rights Management.

Sensor Settings Overview

For more information about sensor settings, see the following sections: