Class: QgsLogger

Responsible for printing debug/warning/error messages to the console.

The advantage of this class over iostream & co. is that the output can be controlled with environment variables: QGIS_DEBUG is an int describing what debug messages are written to the console. If the debug level of a message is <= QGIS_DEBUG, the message is written to the console. It the variable QGIS_DEBUG is not defined, it defaults to 1 for debug mode and to 0 for release mode QGIS_DEBUG_FILE may contain a file name. Only the messages from this file are printed (provided they have the right debuglevel). If QGIS_DEBUG_FILE is not set, messages from all files are printed

QGIS_LOG_FILE may contain a file name. If set, all messages will be appended to this file rather than to stdout.

class qgis.core.QgsLogger

Bases: object

static critical(msg: str | None)

Goes to qCritical.

Parameters:

msg (Optional[str])

debug(msg: str | None, debuglevel: int = 1, file: str | None = None, function: str | None = None, line: int = -1)

Goes to qDebug.

Parameters:

• msg (Optional[str]) – the message to be printed

• debuglevel (int = 1)

• file (Optional[str] = None) – file name where the message comes from

• function (Optional[str] = None) – function where the message comes from

• line (int = -1) – place in file where the message comes from

debug(var: Optional[str], val: int, debuglevel: int = 1, file: Optional[str] = None, function: Optional[str] = None, line: int = -1) Similar to the previous method, but prints a variable int-value pair

static debugLevel() → int

Reads the environment variable QGIS_DEBUG and converts it to int. If QGIS_DEBUG is not set, the function returns 1 if QGISDEBUG is defined and 0 if not.

Return type:

int

static fatal(msg: str | None)

Goes to qFatal.

Parameters:

msg (Optional[str])

static logFile() → str

Reads the environment variable QGIS_LOG_FILE. Returns an empty string if the variable is not set, otherwise returns a file name for writing log messages to.

Return type:

str

static logMessageToFile(message: str | None)

Logs the message passed in to the logfile defined in QGIS_LOG_FILE if any.

Parameters:

message (Optional[str])

static warning(msg: str | None)

Goes to qWarning.

Parameters:

msg (Optional[str])