Log middleware has problem receiving log level setting

[jackalcooper]

When I set it to :error

When I set it to :info

But there are all requests with 200 HTTP status code.

This is the log setting in my client:

middleware Maxwell.Middleware.Logger, [log_level: :info]

[zhongwencool]

Now:
Logger middleware will log all requests by Logger(even 200 code).
Logger writes log according to log_level(error, info, warning, debug).

But:
Add a option to decide which request should not logged will be better.@secretworry

   middleware Maxwell.Middleware.Logger, [code: 200]

And change default behavior to not logged 200 code.

[secretworry]

@zhongwencool Yes, but I think a better solution would be providing a mechanism to let the user define which status code should be logged in which log_level. For example, combining the option log_level and codes would do this job.
To log all requests in info level

middleware Maxwell.Middleware.Logger, [log_level: :info]

To log 2xx with info, others with error

middleware Maxwell.Middleware.Logger, log_level: :info, codes: 200..299
middleware Maxwell.Middleware.Logger, log_level: :error, codes: [0..199, 300..999]

But this method is too verbose for defining an exclusive case. Another idea is to use log_level to provide default log level, and use codes as a mapping from codes to log_level to define special cases.

middleware Maxwell.Middleware.Logger, log_level: :error, codes: %{200..299 => :info, 300..399 => :warn}

@zhongwencool any other ideas?

[zhongwencool]

I like the second idea~
but I want to put default log level into map:

middleware Maxwell.Middleware.Logger, log_level: [200..299 => :info,
                             300..399 => :warn, :default => :error]

[falood]

I have some suggestion about the DSL.

1. we use Keyword not Map for options
2. the number of status code is unsure but the number of log_level is 5
   so, how about such DSL? it's customized for complex requirements, but too long for simple use case 😞

middleware Maxwell.Middleware.Logger, log_level: [
  info: [1..100, 200..299],
  warn: 300..399,
  error: [:default, 123, 400..599],
]

[jackalcooper]

I got to say I kind of like @falood 's idea. Besides the keyword list accepting a callback could be even better.

[secretworry]

@zhongwencool I don't think putting default value together with special values is a good idea.
So adding an option :default_level with default value :error would be more simple and clear.

middleware Maxwell.Middleware.Logger
# are equivalent to
middleware Maxwell.Middleware.Logger default: :error, log_level: %{200..299: :info, 300..399: :warn}

@falood I agree with your suggestion on using the level as key. The concern here is the level of the log, so using it as the key would be more concise.
Besides, your example can be simplified as

middleware Maxwell.Middleware.Logger, default_level: :error, log_level: [
  info: [1..100, 200..299],
  warn: 300..399
]
# or with using :error as default level
middleware Maxwell.Middleware.Logger, log_level: [
  info: [1..100, 200..299],
  warn: 300..399
]

[secretworry]

@jackalcooper Using an inline function as an argument of the macro is not easy and will make this middleware be too complicate. If you have more complicated filtering conditions, writing a customized middleware would be a better solution.

[falood]

so, the default level don't need other value, how about use follow DSL, I think it's clear enough.

middleware Maxwell.Middleware.Logger, level: [
  info: [1..100, 200..299],
  warn: 300..399,
  error: :default
]

if default level missed, I think it's better ignore the missed status code.
people who just want error log, should use

middleware Maxwell.Middleware.Logger, level: [
  error: 400..599
]