I mean this code
kokolegorille
sc4224
** (Mix) Could not start application my_app: MyApp.Application.start(:normal, ) returned an error: shutdown: failed to start child: MyApp.Registry
** (EXIT) an exception was raised:
** (UndefinedFunctionError) function MyApp.Registry.start_link/0 is undefined or private. Did you mean one of:
* start_link/1
I added worker(MyApp.Registry, ) to children
0
kokolegorille
sc4224
genserver
defmodule MyApp.Registry do
use GenServer
def start_link(opts) do
GenServer.start_link(__MODULE__, :ok, opts)
end
def lookup(server, name) do
GenServer.call(server, {:lookup, name})
end
def create(server, name) do
GenServer.cast(server, {:create, name})
end
def init(:ok) do
names = %{}
refs = %{}
{:ok, pubsub} = Redix.PubSub.start_link()
Redix.PubSub.subscribe(pubsub, "my_channel", self())
{:ok, {names, refs}}
end
def handle_call({:lookup, name}, _from, {names, _} = state) do
{:reply, Map.fetch(names, name), state}
end
def handle_cast({:create, name}, {names, refs}) do
if Map.has_key?(names, name) do
{:noreply, {names, refs}}
else
{:ok, pid} = MyApp.Bucket.start_link([])
ref = Process.monitor(pid)
refs = Map.put(refs, ref, name)
names = Map.put(names, name, pid)
{:noreply, {names, refs}}
end
end
def handle_info({:DOWN, ref, :process, _pid, _reason}, {names, refs}) do
{name, refs} = Map.pop(refs, ref)
names = Map.delete(names, name)
{:noreply, {names, refs}}
end
def handle_info(_msg, state) do
{:noreply, state}
end
end
0
kokolegorille
As mentionned in your error message, You need to pass an argument to start_link. Something like…
opts = whatever
worker(MyApp.Registry, [opts])
0
sc4224
kokolegorille
I would not use receive blocks… Instead, I would use handle_info to catch message. This is also described in the link mentionned before about GenServer.
0
sc4224
kokolegorille
You might start to see messages appears with
def handle_info(msg, state) do
inspect msg
{:noreply, state}
end
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