Here's your chance to inflict chaos and destruction on your Elixir runtime.
The GenServer CrashyMcCrashFace has two API functions, crash and
exit.
If you call exit, the server does a normal exit. If you call
crash, it exits with an error.
The top-level of the application, in lib/crashy.ex, starts three
copies of McCrashFace, with the names :one, :two, and :three.
These three workers are supervised.
You can run the application and call either exit or crash with:
mix run -e "Crashy.McCrashFace.exit :two"
mix run -e "Crashy.McCrashFace.crash :two"
When you do so, the app will trace what happens—you'll see workers terminate and possibly restart:
Change the values of the :strategy and :restart options in
lib/crashy.ex. There are nine combinations in all. For each, run
mix run -e "Crashy.McCrashFace.exit :two"
mix run -e "Crashy.McCrashFace.crash :two"
and record in the following table which workers are stopped by each
command, and which workers are subsequently restarted. I've filled in
some entries for you. I show workers that are terminated using - and
a list of numbers, and those that are subsequently restarted using +
and their numbers
| restart | call | one_for_one | one_for_all | rest_for_one |
|---|---|---|---|---|
| permanent | exit | -2 +2 | ||
| crash | -2 +2 | |||
| transient | exit | -2 | ||
| crash | -123 +123 | |||
| temporary | exit | -2 | ||
| crash | -2 |