mod_arm4 - Apache 2 Application Response Measurement (ARM) module

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mod_arm4 - Apache 2 Application Response Measurement (ARM) module

This module makes the Apache HTTP Server version 2.0 and 2.2 aware of and a participant in ARM instrumentation flows. This module requires the services of an ARM agent library. See http://www.opengroup.org/management/arm/.

With this module it is possible to measure each HTTP request made to a Apache HTTP Server using the Application Response Measurement (ARM) standard. This module only interfaces to the ARM 4.0 C interface and therefore you need a real ARM 4.0 compliant agent to really measure HTTP requests. If the module does not find any agent library (libarm4.so) the module is disabled at runtime. No runtime linking problem occurs!

Features

The mod_arm4 module found at the Apache web-site works but is not really customisable and also not implemented for a production server. We at MyARM improved the module regarding performance, better ARM instrumentation and added various configuration directives to selectively measure HTTP requests. The following lists the main features of the mod_arm4 module:

Load the ARM library dynamically
Measurement of requests only if a correlator was passed by a client.
Explicitly allow or deny measurement of requests by URI patterns.
Support of ARM context properties (Various HTTP Request information).
Support of ARM metrics (BytesSent, HTTP Status).

Directives

ArmApplicationName Directive

Description: Sets the application name registered with the the ARM agent.
Syntax: ArmApplicationName name
Default: ArmApplicationName Apache HTTP Server
Context: server config

ArmCorrelatorOnly Directive

Description: If enabled only HTTP requests are measured if an ARM correlator was received in the HTTP headers.
Syntax: ArmCorrelatorOnly on|off
Default: ArmCorrelatorOnly off
Context: server config

ArmDebug Directive

Description: Enables log output to the error log stream for debugging the mod_arm4 itself..
Syntax: ArmDebug on|off
Default: ArmDebug off
Context: server config

ArmDisableMatch Directive

Description: Specifies a pattern of URIs to disable for ARM measurements.
Syntax: ArmDisableMatch pattern
Default: None
Context: server config

ArmEnableMatch Directive

Description: Specifies a pattern of URIs to explicitly enable ARM measurements. This pattern overwrites a also matching ArmDisableMatch pattern!
Syntax: ArmEnableMatch pattern
Default: None
Context: server config

ArmInstrumentHandler

Description: ArmInstrumentHandler on causes arm_block|unblock_transaction to be called across content handlers.
Syntax: ArmInstrumentHandler on|off
Default: ArmInstrumentHandler off
Context: server config, directory

ArmLoadLibrary Directive

Description: Sets the path of the ARM4 agent shared library to be loaded during startup.
Syntax: ArmLoadLibrary file-path
Default: ArmLoadLibrary libarm4 (.dll on windows, .a on AIX, .so everywhere else)
Context: server config

ArmProcessing Directive

Description: Enables or disables ARM processing at all for the section it was specified in.
Syntax: ArmProcessing on|off
Default: ArmProcessing on
Context: server config, directory

ArmTransactionContext Directive

Description: Enables association of context properties of the HTTP request to the ARM transaction.
Syntax: ArmTransactionContext on|off
Default: ArmTransactionContext on
Context: server config, directory

ArmTransactionMetrics Directive

Description: Enables association of metrics such as BytesSent and HTTP Status of a HTTP request to the ARM transaction.
Syntax: ArmTransactionMetrics on|off
Default: ArmTransactionMetrics on
Context: server config, directory

ArmTransactionName Directive

Description: Sets the transaction name registered with the ARM agent.
Syntax: ArmTransactionName name
Default: ArmTransactionName HTTP Request
Context: server config

ArmVerbose Directive

Description: Enables log output to the error log stream for basic ARM operations.
Syntax: ArmVerbose on|off
Default: ArmVerbose on
Context: server config