• ​Enabling logging​

• ​Logging options​

• ​Log long-running queries​

• ​Changing default logger​

• ​Using custom logger​

Enabling logging

You can enable logging of all queries and errors by simply setting logging: true in your connection options:

{
    name: "mysql",
    type: "mysql",
    host: "localhost",
    port: 3306,
    username: "test",
    password: "test",
    database: "test",
    ...
    logging: true
}

Logging options

You can enable different types of logging in connection options:

{ 
    host: "localhost",
    ...
    logging: ["query", "error"]
}

If you want to enable logging of failed queries only then only add error:

{
    host: "localhost",
    ...
    logging: ["error"]
}

There are other options you can use:

• query - logs all queries.

• error - logs all failed queries and errors.

• schema - logs the schema build process.

• warn - logs internal orm warnings.

• info - logs internal orm informative messages.

• log - logs internal orm log messages.

You can specify as many options as needed. If you want to enable all logging you can simply specify logging: "all":

{
    host: "localhost",
    ...
    logging: "all"
}

Log long-running queries

If you have performance issues, you can log queries that take too much time to execute by setting maxQueryExecutionTime in connection options:

{
    host: "localhost",
    ...
    maxQueryExecutionTime: 1000
}

This code will log all queries which run more then 1 second.

Changing default logger

TypeORM ships with 4 different types of logger:

• advanced-console - this is the default logger which logs all messages into the console using color

  and sql syntax highlighting (using chalk).

• simple-console - this is a simple console logger which is exactly the same as the advanced logger, but it does not use any color highlighting.

  This logger can be used if you have problems / or don't like colorized logs.

• file - this logger writes all logs into ormlogs.log in the root folder of your project (near package.json and ormconfig.json).

• debug - this logger uses debug package, to turn on logging set your env variable DEBUG=typeorm:* (note logging option has no effect on this logger).

You can enable any of them in connection options:

{
    host: "localhost",
    ...
    logging: true,
    logger: "file"
}

Using custom logger

You can create your own logger class by implementing the Logger interface:

import {Logger} from "typeorm";
​
export class MyCustomLogger implements Logger {
​
    // implement all methods from logger class
​
}

And specify it in connection options:

import {createConnection} from "typeorm";
import {MyCustomLogger} from "./logger/MyCustomLogger";
​
createConnection({
    name: "mysql",
    type: "mysql",
    host: "localhost",
    port: 3306,
    username: "test",
    password: "test",
    database: "test",
    logger: new MyCustomLogger()
});

If you defined your connection options in the ormconfig file, then you can use it and override it in the following way:

import {createConnection, getConnectionOptions} from "typeorm";
import {MyCustomLogger} from "./logger/MyCustomLogger";
​
// getConnectionOptions will read options from your ormconfig file
// and return it in connectionOptions object
// then you can simply append additional properties to it
getConnectionOptions().then(connectionOptions => {
    return createConnection(Object.assign(connectionOptions, {
        logger: new MyCustomLogger()
    }))
});

Logger methods can accept QueryRunner when it's available. It's helpful if you want to log additional data. Also, via query runner, you can get access to additional data passed during persist/remove. For example:

// user sends request during entity save
postRepository.save(post, { data: { request: request } });
​
// in logger you can access it this way:
logQuery(query: string, parameters?: any[], queryRunner?: QueryRunner) {
    const requestUrl = queryRunner && queryRunner.data["request"] ? "(" + queryRunner.data["request"].url + ") " : "";
    console.log(requestUrl + "executing query: " + query);
}