Fix #405 by providing a better way to configure logger

[seratch]

Summary

This pull request fixes #405 by changing the initialization of the App instances a bit. The changes included in this PR are:

• Set the logger name for the default one
• Change the default values for logger, logLevel arguments of App constructor to distinguish they're explicitly specified or not
• Stop sharing a single logger with WebClient as WebClient has its own logger initialization logics - in other words, only the logLevel will be shared between Bolt apps and WebClient

The behavior

The log output with this fix will be more straight-forward.

If a developer goes with the default settings (default ConsoleLogger and LogLevel.INFO) gives only logLevel to the App constructor as below,

const { LogLevel } = require("@slack/logger");
const { App } = require("@slack/bolt");
const app = new App({
  logLevel: LogLevel.DEBUG,
  token: process.env.SLACK_BOT_TOKEN,
  signingSecret: process.env.SLACK_SIGNING_SECRET
});

The logger shows the following outputs.

[DEBUG]  WebClient:0 initialized
[DEBUG]  WebClient:0 apiCall('auth.test') start
[DEBUG]  WebClient:0 will perform http request
⚡️ Bolt app is running!
[DEBUG]  WebClient:0 http response received
[DEBUG]  WebClient:1 initialized
[DEBUG]  bolt-app Conversation context not loaded: Conversation not found

If a developer wants to customize the logger name, doing as below works.

const { LogLevel, ConsoleLogger } = require("@slack/logger");
const logger = new ConsoleLogger();
logger.setName('my-bolt-app');
logger.setLevel(LogLevel.DEBUG);

const { App } = require("@slack/bolt");
const app = new App({
  logger: logger,
  token: process.env.SLACK_BOT_TOKEN,
  signingSecret: process.env.SLACK_SIGNING_SECRET
});

The output can be like this. The only last line is different from the default logger.

[DEBUG]  WebClient:0 initialized
[DEBUG]  WebClient:0 apiCall('auth.test') start
[DEBUG]  WebClient:0 will perform http request
⚡️ Bolt app is running!
[DEBUG]  WebClient:0 http response received
[DEBUG]  WebClient:1 initialized
[DEBUG]  my-bolt-app Conversation context not loaded: Conversation not found

If a developer gives both logger and logLevel, Bolt gives priority to logLevel than logger's log level (the log level in logger will be overwritten by the logLevel while the initialization). This behavior is compatible with the past versions so that I think we should not change it at least this time.

Next Steps

I'm sure this improvement should be applied to both Bolt v1 and v2. Once other maintainers approve this change, I will make another PR that brings the same change to the v2 branch later on.

Requirements (place an x in each [ ])

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[codecov]

Codecov Report

Merging #406 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master    #406   +/-   ##
======================================
  Coverage    81.5%   81.5%           
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  Files           7       7           
  Lines         530     530           
  Branches      152     152           
======================================
  Hits          432     432           
  Misses         70      70           
  Partials       28      28

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[seratch]

If someone has suggestions for the default name, leave comments here.

[stevengill]

Seems fine to me

[stevengill]

Seems fine to me

[stevengill]

Are we still setting LogLevel.INFO as the default somewhere? Looks like we lost that logic.

[seratch]

The default is INFO - https://github.com/slackapi/node-slack-sdk/blob/%40slack/logger%402.0.0/packages/logger/src/index.ts#L90

[stevengill]

Okay rad!

[seratch]

@stevengill Thanks for your review!
Once I get approval on this, we can merge this. Also, I will make a PR for the v2 branch.

[seratch]

@stevengill This one seems to already look good to you but just in case can you approve this? (no rush)