xtr Namespace Reference

High-level API for maintaining a global X-Trace context and reporting events with logging-like calls. More...

Data Structures
class	Context
	Represents an X-Trace context, which carries information about the current task and the most recent preceding event in a thread. More...
class	EventEdge
	Represents an edge in an X-Trace graph, i.e., a causal relationship between two events. More...
class	Event
	Represents an X-Trace Event, with enough information to generate an X-Trace report. More...
class	Id
	Represents an id as an array of bytes with a maximum length. More...
class	OpId
	Represents the id of an event, which should be unique within a single task. More...
class	TaskId
	Represents the id of an X-Trace task. More...
class	Options
	Represents the list of options in the X-Trace metadata. More...
class	Metadata
	Represents an X-Trace metadata. More...
class	Option
	Represents an X-Trace metadata option. More...
class	OptionNop
	A No-op option for X-Trace, serialized to a single '0' byte. More...
class	OptionAny
	This class can represent any option, and is used when we don't have a specific class for an option. More...
class	OptionChainId
	A ChainId X-Trace metadata option. More...
class	OptionSeverity
	A Severity X-Trace metadata option. More...
class	Reporter
Functions
void	xtr_btoh (u_int8_t b, char *p)

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Detailed Description

High-level API for maintaining a global X-Trace context and reporting events with logging-like calls.

A Reporter is a static class used to send reports to the reporting daemon.

Usage:

• When communication is received, set the context using Context::setContext().
• To record an event, call Context::logEvent(). Or, to add extra fields to the event report, call Context.prepareEvent(), add fields to the returned Event object, and send it using Context::logEvent(Event *,...).
• When calling another service, get the current context using Context::getContext() and set it as metadata. After receiving a reply, add an edge from both the reply's metadata and the current context in the report for the reply. Serialization and deserialization are done with the methods in Metadata: Metadata::pack() serializes to bytes, Metadata::toString() serializes to a string; Metadata::createFromBytes() and Metadata::createFromString() do what their names say.
• Clear the context using Context.unsetContext()

Author:

Rodrigo Fonseca

Nick Lanham (multi-thread support)

It must be initialized with the static method Reporter::init(), and then any number of reports can be sent using the static method(s) Reporter::sendReport. The reports are sent via UDP to a local socket. The port is by default XTR_RPT_UDP_PORT = 7831, but this setting is overridden if the environment variable XTR_DAEMON_PORT.

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Function Documentation

void xtr::xtr_btoh	(	u_int8_t	b,
		char *	p
	)

Referenced by xtr::Id< max_len >::toString().