Wt
3.2.0
|
A simple logging class. More...
#include <Wt/WLogger>
Classes | |
class | Field |
Class that holds the configuration for a single field. More... | |
struct | Sep |
Class that indicates a field separator. More... | |
struct | TimeStamp |
Class that indicates a time stamp. More... | |
Public Member Functions | |
WLogger () | |
Creates a new logger. | |
~WLogger () | |
Destructor. | |
void | setStream (std::ostream &o) |
Sets the output stream. | |
void | setFile (const std::string &path) |
Sets the output file. | |
void | configure (const std::string &config) |
Configures what things are logged. | |
void | addField (const std::string &name, bool isString) |
Adds a field. | |
const std::vector< Field > & | fields () const |
Returns the field list. | |
WLogEntry | entry (const std::string &type) const |
Starts a new log entry. | |
bool | logging (const std::string &type) const |
Returns whether messages of a given type are logged. | |
bool | logging (const std::string &type, const std::string &scope) const |
Returns whether messages of a given type and scope are logged. | |
Static Public Attributes | |
static const Sep | sep = WLogger::Sep() |
Field separator constant. | |
static const TimeStamp | timestamp = WLogger::TimeStamp() |
Timestamp field constant. | |
Related Functions | |
(Note that these are not member functions.) | |
WLogEntry | log (const std::string &type) |
Logging function. |
A simple logging class.
This class logs events to a stream in a flexible way. It allows to create log files using the commonly used Common Log Format or Combined Log Format, but provides a general way for logging entries that consists of a fixed number of fields.
It is used by Wt to create the application log (WApplication::log()), and built-in httpd access log.
To use this class for custom logging, you should instantiate a logger, add one or more field definitions using addField(), and set an output stream using setStream() or setFile(). To stream data to the logger, use entry() to start formatting a new entry.
Usage example:
// Setup the logger Wt::WLogger logger; logger.addField("datetime", false); logger.addField("session", false); logger.addField("type", false); logger.addField("message", true); logger.setFile("/tmp/mylog.txt"); // Add an entry Wt::WLogEntry entry = logger.entry(); entry << Wt::WLogger::timestamp << Wt::WLogger::sep << '[' << wApp->sessionId() << ']' << Wt::WLogger::sep << '[' << "notice" << ']' << Wt::WLogger::sep << "Succesfully started.";
Wt::WLogger::WLogger | ( | ) |
Creates a new logger.
This creates a new logger, which defaults to logging to stderr.
void Wt::WLogger::addField | ( | const std::string & | name, |
bool | isString | ||
) |
Adds a field.
Add a field to the logger. When isString
is true
, values will be quoted.
void Wt::WLogger::configure | ( | const std::string & | config | ) |
Configures what things are logged.
The configuration is a string that defines rules for enabling or disabling certain logging. It is a white-space delimited list of rules, and each rule is of the form:
[-]level
: enables (or disables) logging of messages of the given level; '*' is a wild-card that matches all levels[-]level:scope
: enables (or disables) logging of messages of the given level and scope; '*' is a wild-card that matches all levels or scopes.The default configuration is "* -debug"
, i.e. by default everything is logged, except for "debug" messages.
Some other examples:
"* -debug debug:wthttp"
: logs everything, including debugging messages of scope "wthttp", but no other debugging messages."* -info -debug"
: disables logging of info messages in addition to debugging messages.WLogEntry Wt::WLogger::entry | ( | const std::string & | type | ) | const |
Starts a new log entry.
Returns a new entry. The entry is logged in the destructor of the entry (i.e. when the entry goes out of scope).
The type
reflects a logging level. You can freely choose a type, but these are commonly used inside the library:
bool Wt::WLogger::logging | ( | const std::string & | type | ) | const |
Returns whether messages of a given type are logged.
Returns true
if messages of the given type are logged. It may be that not messages of all scopes are logged.
bool Wt::WLogger::logging | ( | const std::string & | type, |
const std::string & | scope | ||
) | const |
Returns whether messages of a given type and scope are logged.
void Wt::WLogger::setFile | ( | const std::string & | path | ) |
Sets the output file.
Opens a file output stream for path
. The default logger outputs to stderr.
void Wt::WLogger::setStream | ( | std::ostream & | o | ) |
WLogEntry log | ( | const std::string & | type | ) | [related] |
Logging function.
This creates a new log entry, e.g.:
Wt::log("info") << "Doing something interesting now with " << appleCount() << " apples.";
const WLogger::Sep Wt::WLogger::sep = WLogger::Sep() [static] |
Field separator constant.
const WLogger::TimeStamp Wt::WLogger::timestamp = WLogger::TimeStamp() [static] |
Timestamp field constant.