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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.
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 logmessageLogger.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:
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
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2024-12-02 UTC."],[[["\u003cp\u003eThe \u003ccode\u003eLogger\u003c/code\u003e class enables developers to write text to debugging logs for script analysis and troubleshooting.\u003c/p\u003e\n"],["\u003cp\u003eIt provides methods to clear the log, retrieve the entire log as a string, and write formatted or unformatted messages to the log.\u003c/p\u003e\n"],["\u003cp\u003eLogged output can be viewed within the Apps Script editor using "View > Show logs" and utilized for debugging purposes.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003egetLog()\u003c/code\u003e method allows for capturing the log content, which can then be used for saving, emailing, or further processing.\u003c/p\u003e\n"],["\u003cp\u003eDevelopers can leverage format strings and values to create structured log messages using the \u003ccode\u003elog(format, values)\u003c/code\u003e method.\u003c/p\u003e\n"]]],[],null,["Logger\n\nThis class allows the developer to write to the Execution log and to [Google Cloud Logging](https://cloud.google.com/logging) if the script is associated with\na [standard\nCloud Project](https://developers.google.com/apps-script/guides/cloud-platform-projects#standard). This class is preferred for structured logging and `json``Payload` support\nin Cloud Logging. For time-based logging, use [console](/apps-script/reference/base/console). \n\nMethods\n\n| Method | Return type | Brief description |\n|-----------------------------------------------|-------------|-----------------------------------------------------------------------------------------|\n| [clear()](#clear()) | `void` | Clears the log. |\n| [getLog()](#getLog()) | `String` | Returns a complete list of messages in the current log. |\n| [log(data)](#log(Object)) | [Logger](#) | Writes the data to the log. |\n| [log(format, values)](#log(String,Object...)) | [Logger](#) | Writes a formatted string to the logging console, using the format and values provided. |\n\nDetailed documentation \n\n`clear()` \nClears the log.\n\n*** ** * ** ***\n\n`get``Log()` \nReturns a complete list of messages in the current log. This method can be used to save or\nemail the entire log output generated during script execution.\n\n```javascript\n// Generate a log, then email it to the person who ran the script.\nconst files = DriveApp.getFiles();\nwhile (files.hasNext()) {\n Logger.log(files.next().getName());\n}\nconst recipient = Session.getActiveUser().getEmail();\nconst subject = 'A list of files in your Google Drive';\nconst body = Logger.getLog();\nMailApp.sendEmail(recipient, subject, body);\n```\n\nReturn\n\n\n`String` --- the log from the logging console\n\n*** ** * ** ***\n\n`log(data)` \nWrites the data to the log. The data can be a string, a JavaScript object, or an object with a\n`message` property.\n\n```javascript\nLogger.log(\"my log message\");\n// Info my logmessage\nLogger.log({ key: \"value\" });\n// Info {key=value}\nLogger.log({ message: \"my log message\", data: { key: \"value\" } })\n// Info my logmessage\n```\n\nWhen passing an object, if the object contains a `message` property, that property is\nused as the log message. Otherwise, the `to``String()` method is called to convert the\nobject to a string. All other properties which are JSON serializable are included as part of\nthe `json``Payload` in the [`Log``Entry`](https://cloud.google.com/logging/docs/reference/v2/rest/v2/LogEntry), similar to the example below:\n\n```transact-sql\n{\n \"insertId\": \"w5eib...\",\n \"jsonPayload\": {\n \"message\": \"my log message\",\n \"serviceContext\": {\n \"service\": \"AKfyc...\"\n },\n \"data\": {\n \"key\": \"value\"\n }\n },\n \"resource\": {\n \"type\": \"app_script_function\",\n \"labels\": {\n \"invocation_type\": \"editor\",\n \"function_name\": \"unknown\",\n \"project_id\": \"1234567890\"\n }\n },\n \"timestamp\": \"2024-11-15T23:28:19.448591Z\",\n \"severity\": \"INFO\",\n \"labels\": {\n \"script.googleapis.com/user_key\": \"AOX2d...\",\n \"script.googleapis.com/process_id\": \"EAEA1...\",\n \"script.googleapis.com/project_key\": \"MQXvl...\",\n \"script.googleapis.com/deployment_id\": \"AKfyc...\"\n },\n \"logName\": \"projects/[PROJECT_ID]/logs/script.googleapis.com%2Fconsole_logs\",\n \"receiveTimestamp\": \"2024-11-15T23:28:20.363790313Z\"\n}\n```\n\nParameters\n\n| Name | Type | Description |\n|--------|----------|-------------------|\n| `data` | `Object` | the object to log |\n\nReturn\n\n\n[Logger](#) --- the Logger, for chaining.\n\n*** ** * ** ***\n\n`log(format, values)` \nWrites a formatted string to the logging console, using the format and values provided. The\nstring can include multiple `%s` placeholders, which are replaced with corresponding\nvalues from the list of arguments, converted to strings.\n\n```javascript\n// Log the number of Google Groups you belong to.\nconst groups = GroupsApp.getGroups();\nLogger.log('You are a member of %s Google Groups.', groups.length);\n```\n\nParameters\n\n| Name | Type | Description |\n|----------|-------------|---------------------------------------------------------------------------------------------|\n| `format` | `String` | a format string that contains as many instances of `%s` as the number of `values` arguments |\n| `values` | `Object...` | a variable number of values to insert into the format string |\n\nReturn\n\n\n[Logger](#) --- the Logger, for chaining"]]
