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Wt
4.10.4
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A simple logging class. More...
#include <Wt/WLogger.h>
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 char *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 |
| Field separator constant. | |
| static const TimeStamp | timestamp |
| Timestamp field constant. | |
Related Symbols | |
(Note that these are not member symbols.) | |
| 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:
| Wt::WLogger::WLogger | ( | ) |
Creates a new logger.
This creates a new logger, which defaults to logging to stderr.
Adds a field.
Add a field to the logger. When isString is true, values will be quoted.
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.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:
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.
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.
Returns whether messages of a given type and scope are logged.
Sets the output file.
Opens a file output stream for path. The default logger outputs to stderr.
This logs a message notifying the user whether the file was successfully opened for writing to the previous ostream (usually std::cerr).
If you want to suppress the info message, you can configure the logger with "-info:WLogger". The error when the file was not successfully opened is logged at the error log level.
| void Wt::WLogger::setStream | ( | std::ostream & | o | ) |
Logging function.
This creates a new log entry, e.g.:
Field separator constant.
Timestamp field constant.