Log Reader Binding

This binding reads and analyzes log files. Search patterns are fully configurable, therefore different kind of log files should be possible to monitor by this binding. When certain log events are recognized, openHAB rules can be used to send notification about the event e.g by email for further analysis.

Supported Things

This binding supports one ThingType: reader. A reader supports 3 separate channels

• One for errors
• one for warnings
• one custom channel for other purposes.

Thing Configuration

The reader Thing has the following configuration parameters:

Parameter	Type	Required	Default if omitted	Description
filePath	String	yes	${OPENHAB_LOGDIR}/openhab.log	Path to log file. ${OPENHAB_LOGDIR} is automatically replaced by the correct directory.
refreshRate	integer	no	1000	Time in milliseconds between individual log reads.
errorPatterns	String	no	ERROR+	Search patterns separated by | character for error events.
errorBlacklistingPatterns	String	no		Search patterns for blacklisting unwanted error events separated by | character.
warningPatterns	String	no	WARN+	Search patterns separated by | character for warning events.
warningBlacklistingPatterns	String	no		Search patterns for blacklisting unwanted warning events separated by | character.
customPatterns	String	no		Search patterns separated by | character for custom events.
customBlacklistingPatterns	String	no		Search patterns for blacklisting unwanted custom events separated by | character.

Search patterns follows Java regular expression syntax. See https://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html (opens new window).

Channels

List of channels

Channel Type ID	Item Type	Description
lastErrorEvent	String	Displays content of last [ERROR] event
lastWarningEvent	String	Displays content of last [WARN] event
lastCustomEvent	String	Displays content of last [CUSTOM] event
errorEvents	Number	Displays number of [ERROR] lines matched to search pattern
warningEvents	Number	Displays number of [WARN] lines matched to search pattern
customEvents	Number	Displays number of [CUSTOM] lines matched to search pattern
logRotated	DateTime	Last time when log rotated recognized
newErrorEvent	-	Trigger channel for last [ERROR] line
newWarningEvent	-	Trigger channel for last [WARN] line
newCustomEvent	-	Trigger channel for last [CUSTOM] line

Examples

example.things

logreader:reader:openhablog[ refreshRate=1000, errorPatterns="ERROR+", errorBlacklistingPatterns="annoying error which should be ignored|Another annoying error which should be ignored" ]

example.items

DateTime logreaderLogRotated        "Last Log Rotation [%1$tY.%1$tm.%1$te %1$tR]"   <time>  { channel="logreader:reader:openhablog:logRotated" }
Number   logreaderErrors            "Error events matched [%d]"                     <alarm> { channel="logreader:reader:openhablog:errorEvents" }
String   logreaderLastError         "Last error [%s]"                                       { channel="logreader:reader:openhablog:lastErrorEvent" }
Number   logreaderWarnings          "Warning events matched [%d]"                   <alarm> { channel="logreader:reader:openhablog:warningEvents" }
String   logreaderLastWarning       "Last warning [%s]"                                     { channel="logreader:reader:openhablog:lastWarningEvent" }
Number   logreaderCustoms           "Custom events matched [%d]"                    <alarm> { channel="logreader:reader:openhablog:customEvents" }
String   logreaderLastCustom        "Last Custom [%s]"                                      { channel="logreader:reader:openhablog:lastCustomEvent" }

example.sitemap

sitemap logreader_example label="Example" {
	Frame label="openHAB Log Reader" {
		Text item=logreaderErrors
		Text item=logreaderLastError
		Text item=logreaderWarnings
		Text item=logreaderLastWarning
		Text item=logreaderCustoms
		Text item=logreaderLastCustom
		Text item=logreaderLogRotated
	}
}

example.rules

rule "LogReader"
    when
        Channel "logreader:reader:openhablog:newErrorEvent" triggered
    then
        // do something
    end

Use the rules with your Telegram Bot (need openHAB Telegram Binding installed and configured)

rule "LogReader"
    when
        Channel 'logreader:reader:openhablog:newErrorEvent' triggered
    then
        val telegramAction = getActions("telegram","telegram:telegramBot:myBot")
        telegramAction.sendTelegram("*ERROR* LogReader Event!\n%s Errors are in the log! Here is the last row of it:\n`%s`", logreaderErrors.state.toString, logreaderLastError.state.toString)
    end

Be careful when sending e.g. email notifications. You could easily send thousand of spam emails in short period if e.g. one binding is in error loop.

Thing status

Check thing status for errors.

Verbose logging

Enable DEBUG logging in karaf console to see more precise error messages:

log:set DEBUG org.openhab.binding.logreader

See openHAB2 logging docs (opens new window) for more help.

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