Intro
I will continue add tips & tricks for develop/debugging with Elixir in this topic for sharing my experiences about Elixir.
Add .iex.exs file for easy develop & debug
Add .iex.exs file to root folder of Elixir app then:
1. Add alias to avoid type much
example add
alias MyApp.Background.Worker, as: W
defmodule FillData do
def add_sample() do
Cache.add_room(:hello, "Hello room", nil)
Cache.add_room_members(:hello, ["user_1", "user_2", "user_3"], nil)
end
end
to your .iex.exs and run with iex -S mix
or iex -S mix phx.server
then in Elixir shell you can type like:
W.run()
# For add sample data for developing
FillData.add_sample() # Or add directly to .iex.exs
2. Add function/script support for debugging.
You can add a script or function needed for debugging then run in Elixir shell.
rescue in body function
when define a function you can directly use rescue
in body without try
keyword.
Example:
def server_info(endpoint, scheme) do
address =
endpoint
|> make_ref(scheme)
|> :ranch.get_addr()
{:ok, address}
rescue
e -> {:error, Exception.message(e)}
end
(code from :swarm
library)
Add support :observer
:observer
is interesting tool for view system statistics, app structure like supervisor, process, ets table,...
We can add to dev mode to mix.exs file like:
defmodule MyApp.MixProject do
# ...
def application do
dev_app =
case Mix.env() do
:dev -> [:observer, :wx]
_ -> []
end
required_app = [:logger, :runtime_tools]
[
mod: {EmbeddedChat.Application, []},
extra_applications: required_app ++ dev_app
]
end
end
Now, when you start dev mode you can start :observer by simple command :observer.start()
Note: :observer
need graphic library to show system data then we need to start it on a OS support that (Windows/macOS/Linux with graphic). For case need view system that doesn't have graphic library like container in Kubernetes cluster, we can join to remote node from other machine and start :observer
.
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