只有在行尾使用`rescue`才能捕获异常，但在使用`begin rescue`块时则不会

Question

I have a statement that fails:

result = service.load_data()

Now the following suppresses the error and I can then check for nil

result = service.load_data() rescue nil

But when I do the following the initial error is thrown right up to the UI and I don't get the details of the exception.

begin
   result = service.load_data()
rescue => details         
   logger.fatal "Failed to load the data: #{details}"
end

I am sure there is a silly detail I must be missing but I can't seem to spot the problem here. So why isn't the rescue block invoked?

Update: The error I got was this:

getaddrinfo: nodename nor servname provided, or not known

Answer 1

begin
   result = service.load_data()
rescue AnExceptionKlass => details    # here the name is SocketError    
   logger.fatal "Failed to load the data: #{details}"
end

use the above.

tried to replicate the error here as below:

require 'net/http'
Net::HTTP.start('http://www.google.com') do |http|
response = http.get('/')
puts response
end
#=> getaddrinfo: No such host is known.  (SocketError)

Fixed it as below:

require 'net/http'

begin

  htt = Net::HTTP.start('http://www.google.com')
  response = htt.get('/')
  puts response

rescue SocketError => details    # or the Exception class name may be SocketError    
   p "Failed to load the data: #{details}"
end

#=> "Failed to load the data: getaddrinfo: No such host is known. "