undefined method `each' for nil:NilClass - But why? - ruby-on-rails

Question

I want to create a ruby app to check if a server status is up or down.
Later I will find a way to adapt my json path to find a way in the diverse syntax. But for now, I'm stuck with a dirty "undefined method `each' for nil:NilClass"
Ping controller:
def index
#pings = Ping.all
end
def new
#service = Ping.new
end
def create
#ping = Ping.new(ping_params)
#ping.service = #service
#ping.up = test_ping
#ping.save
end
def test_ping
require 'json'
require 'open-uri'
url = 'https://www.facebook.com/platform/api-status/'
fb_status_serialized = open(url).read
fb_status = JSON.parse(fb_status_serialized)
if fb_status['current']['health'] == 1
test_ping = true
else
test_ping = false
end
end
private
def ping_params
params.require(:ping).permit(:service_id, :up)
end
def set_ping
#ping = Ping.find(params[:ping_id])
end
end
Service controller:
(here are my setup for the services I want to add)
class ServiceController < ApplicationController
before_action :set_service, only: [:edit, :show, :destroy]
def index
#services = Service.all
end
def new
#service = Service.new
end
def edit
end
def show
end
def create
#service = Service.new(service_params)
#service.save
if #service.save
redirect_to service_path(#service)
else
render :new
end
end
def destroy
#service.destroy
#service.destroy
redirect_to services_path
end
private
def set_service
#service = Service.find(params[:id])
end
def service_params
params.require(:service).permit(:name, :web_api, :json_path)
end
end
View (service index):
<%= #services.each do | s | %>
<p><%= s.name %></p>
<p><%= s.web_api %></p>
<p><%= s.json_path %></p>
<p><%= s.id %></p>
<%= #pings.each do | p | %>
<%# if p.service_id == s.id %>
<!-- undefined -->
<% end %>
<p>|||</p> <%= Ping.new(up: true, service: s ) %> <p>|||</p>
<% end %>

Answer 1

You're trying to iterate over #pings that are inside the #services iteration, but this hasn't been defined, you've defined only services, and the iteration in pings won't work if the object in which each is being applied has a nil value.
Whatever is the controller you're using to render the view, you need to define both instance variables, try with:
def index
#services = Service.all
#pings = Ping.all
end