Class Logger
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AI-generated Key Takeaways
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The Logger class is used to write to the Execution log and Google Cloud Logging, especially for structured logging and JSON payloads.
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Use the clear() method to clear the log and getLog() to retrieve all messages in the current log.
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The log() method can write various data types to the log, including strings, JavaScript objects, or objects with a message property.
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The log() method also supports writing formatted strings to the log using placeholders and values.
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 json support
in Cloud Logging. For time-based logging, use console .
Methods
| Method | Return type | Brief description |
|---|---|---|
clear() | void | Clears the log. |
get | 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
clear()
Clears the log.
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. constfiles=DriveApp.getFiles(); while(files.hasNext()){ Logger.log(files.next().getName()); } constrecipient=Session.getActiveUser().getEmail(); constsubject='A list of files in your Google Drive'; constbody=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 a
message 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 to method is called to convert the
object to a string. All other properties which are JSON serializable are included as part of
the json in the Log, 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. constgroups=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 of
values arguments |
values | Object... | a variable number of values to insert into the format string |
Return
Logger — the Logger, for chaining