Feature/add config validation

[Daniel1984]

• adding check to verify that actual config has same object keys as config example to avoid running workers with missing configuration.
• added optional validation parameter
• added test coverage
• added linter and fixed few linter warnings
• should we remove package-lock.json from .gitignore?
• not using any 3rd party packages as Joi or similar to avoid extra dependencies and our comparison is pretty simple here
• more info in README.md

[ceecko]

I left a comment in the nested keys example where I think the validation fails.

One more thing I just realized, not really a request for a change, rather a general comment - how do we want to approach optional configuration?

Let's say we have a configuration such as enableSlack: bool.
If it's enabled, the slackAPIKey needs to be populated, otherwise it can be left empty.
The example config shows an example for the slackAPIKey (as expected) but it's not mandatory to be populated in the config if Slack is disabled. This way the validation reports the API key is missing, although it's not mandatory.

It's not clear to me what the best approach would be here. I just wanted to bring this up since there can be this type of configuration options.

[ceecko]

One other topic - how do we want to approach checking configs which are based on a common config?
Such as ERC20 tokens having one example config but each token having a separate config of its own.

[Daniel1984]

I would get back to the original issue we had: if there's a example config, we must ensure all fields are present in config. That is covered and we can improve moving forward

[Daniel1984]

I left a comment in the nested keys example where I think the validation fails.

One more thing I just realized, not really a request for a change, rather a general comment - how do we want to approach optional configuration?

Let's say we have a configuration such as enableSlack: bool. If it's enabled, the slackAPIKey needs to be populated, otherwise it can be left empty. The example config shows an example for the slackAPIKey (as expected) but it's not mandatory to be populated in the config if Slack is disabled. This way the validation reports the API key is missing, although it's not mandatory.

It's not clear to me what the best approach would be here. I just wanted to bring this up since there can be this type of configuration options.

In config:

{
  "slackAPIKey": "xyz"
}

In implementation:

this.loadConf('some.coin', 'coin', { slackAPIKey: { required: true } })

// somewhere else:
if (this.ctx.conf.slackAPIKey) {
  this.ctx.lib.slackClient.send();
}

There's always more than one way to achieve things