Class Logger | Apps Script | Google for Developers (original) (raw)

Class Logger

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Logger

This class allows the developer to write to the Execution log and to Google Cloud Logging if the script is associated with a standard Cloud Project. This class is preferred for structured logging and jsonPayload support in Cloud Logging. For time-based logging, use [console](/apps-script/reference/base/console).

Methods

Method	Return type	Brief description
clear()	void	Clears the log.
getLog()	String	Returns a complete list of messages in the current log.
log(data)	Logger	Writes the data to the log.
log(format, values)	Logger	Writes a formatted string to the logging console, using the format and values provided.

Detailed documentation

`getLog()`

Returns a complete list of messages in the current log. This method can be used to save or email the entire log output generated during script execution.

// Generate a log, then email it to the person who ran the script. const files = DriveApp.getFiles(); while (files.hasNext()) { Logger.log(files.next().getName()); } const recipient = Session.getActiveUser().getEmail(); const subject = 'A list of files in your Google Drive'; const body = Logger.getLog(); MailApp.sendEmail(recipient, subject, body);

Return

String — the log from the logging console

`log(data)`

Writes the data to the log. The data can be a string, a JavaScript object, or an object with amessage property.

Logger.log("my log message"); // Info my logmessage Logger.log({ key: "value" }); // Info {key=value} Logger.log({ message: "my log message", data: { key: "value" } }) // Info my logmessage

When passing an object, if the object contains a message property, that property is used as the log message. Otherwise, the toString() method is called to convert the object to a string. All other properties which are JSON serializable are included as part of the jsonPayload in the LogEntry, similar to the example below:

{ "insertId": "w5eib...", "jsonPayload": { "message": "my log message", "serviceContext": { "service": "AKfyc..." }, "data": { "key": "value" } }, "resource": { "type": "app_script_function", "labels": { "invocation_type": "editor", "function_name": "unknown", "project_id": "1234567890" } }, "timestamp": "2024-11-15T23:28:19.448591Z", "severity": "INFO", "labels": { "script.googleapis.com/user_key": "AOX2d...", "script.googleapis.com/process_id": "EAEA1...", "script.googleapis.com/project_key": "MQXvl...", "script.googleapis.com/deployment_id": "AKfyc..." }, "logName": "projects/[PROJECT_ID]/logs/script.googleapis.com%2Fconsole_logs", "receiveTimestamp": "2024-11-15T23:28:20.363790313Z" }

Parameters

Name	Type	Description
data	Object	the object to log

Return

[Logger](#) — the Logger, for chaining.

`log(format, values)`

Writes a formatted string to the logging console, using the format and values provided. The string can include multiple %s placeholders, which are replaced with corresponding values from the list of arguments, converted to strings.

// Log the number of Google Groups you belong to. const groups = GroupsApp.getGroups(); Logger.log('You are a member of %s Google Groups.', groups.length);

Parameters

Name	Type	Description
format	String	a format string that contains as many instances of %s as the number ofvalues arguments
values	Object...	a variable number of values to insert into the format string

Return

[Logger](#) — the Logger, for chaining

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Last updated 2024-12-02 UTC.