Elixir OTP 24 doesn’t apply custom Logger backend - erlang

Question

I have an umbrella application which has logger configuration in the root config.exs file:
config :logger,
compile_time_purge_level: :debug,
backends: [
{LoggerFileBackend, :backends_log}
]
config :logger, :backends_log,
path: "path/to/awesome.log",
level: :debug,
metadata: :all
After updating OTP from 22 to 24 version (elixir 1.12.3, erlang 24.1), backends_log is not starting and all logs are going to STDOUT with default :console backend. But configuration is still same:
Application.get_all_env(:kernel)
=> [
logger: [
{:handler, :default, :logger_std_h,
%{
config: %{type: :standard_io},
formatter: {:logger_formatter,
%{legacy_header: true, single_line: false}}
}}
],
logger_sasl_compatible: false,
logger_level: :notice,
shell_docs_ansi: :auto
]
Application.get_all_env(:logger)
=> [
handle_sasl_reports: true,
discard_threshold: 5000,
compile_time_purge_matching: [],
sync_threshold: 10000,
utc_log: false,
console: [],
backends_log: [path: "path/to/awesome.log", level: :debug, metadata: :all],
start_options: [],
pdu_format_reviewer_error_count: [level: :error],
compile_time_application: nil,
backends: [
{LoggerFileBackend, :backends_log}
],
discard_threshold_periodic_check: 30000,
translators: [
{Plug.Cowboy.Translator, :translate},
{Logger.Translator, :translate}
],
compile_time_purge_level: :debug,
truncate: 8096,
log_counter: [level: :debug],
handle_otp_reports: true,
discard_threshold_for_error_logger: 500,
translator_inspect_opts: []
]
:logger.get_primary_config()
=> %{
filter_default: :log,
filters: [process_disabled: {&Logger.Filter.process_disabled/2, []}],
level: :debug,
metadata: %{}
}
I can fix this problem with Runtime Configuration
Logger.add_backend({LoggerFileBackend, :backends_log})
Logger.configure_backend(
{LoggerFileBackend, :backends_log},
path: "path/to/awesome.log",
level: :debug,
metadata: :all
)
Logger.remove_backend(Logger.Backends.Console)
but I think Application Configuration is more proper way.
How should I fix this problem?

Answer 1

Your config works for me. My configuration is: Ubuntu2004, Elixir 1.12.2, Erlang 24.1 (ESL Erlang). I tried to recreate your problem. Take a look at it, it might help.
https://github.com/z5ottu/elixir_12_logger_test