Google Colab: gaierror: [Errno -8] Servname not supported for ai_socktype about ntplib HOT 8 CLOSED

Looks like an issue with service resolution.

What does the following return in your environment?

In [5]: socket.getaddrinfo("pool.ntp.org", "ntp", socket.AF_UNSPEC)

And

In [6]: socket.getservbyname("ntp")

from ntplib.

import socket

socket.getaddrinfo("pool.ntp.org", "ntp", socket.AF_UNSPEC)

gives

---------------------------------------------------------------------------
gaierror                                  Traceback (most recent call last)
[<ipython-input-2-50891d166737>](https://localhost:8080/#) in <cell line: 3>()
      1 import socket
      2 
----> 3 socket.getaddrinfo("pool.ntp.org", "ntp", socket.AF_UNSPEC)

[/usr/lib/python3.10/socket.py](https://localhost:8080/#) in getaddrinfo(host, port, family, type, proto, flags)
    953     # and socket type values to enum constants.
    954     addrlist = []
--> 955     for res in _socket.getaddrinfo(host, port, family, type, proto, flags):
    956         af, socktype, proto, canonname, sa = res
    957         addrlist.append((_intenum_converter(af, AddressFamily),

gaierror: [Errno -8] Servname not supported for ai_socktype

from ntplib.

See above, what about?

socket.getservbyname("ntp")

But in any case looks like your environment cannot resolve the "ntp" services - you could try passing the port explicitly:

c.request("pool.ntp.org", version=3, port=123)

from ntplib.

You can replicate this error by simply removing the ntp entry from /etc/services file. Which makes sense. When there is no ntp entry; then the code fails; but is kinda ugly. As port 123 was defined nearly 38 years ago as port 123, it's safe to say that hardcoding it into the code is safe. See:

$ git diff
diff --git a/ntplib.py b/ntplib.py
index 77ae7b7..6f4049e 100644
--- a/ntplib.py
+++ b/ntplib.py
@@ -298,7 +298,11 @@ class NTPClient(object):
         """
 
         # lookup server address
-        addrinfo = socket.getaddrinfo(host, port, address_family)[0]
+        try:
+            addrinfo = socket.getaddrinfo(host, port, address_family)[0]
+        except socket.gaierror:
+            # 123 is defined in Sept/1985 by https://www.rfc-editor.org/rfc/rfc958
+            addrinfo = socket.getaddrinfo(host, 123, address_family)[0]
         family, sockaddr = addrinfo[0], addrinfo[4]
 
         # create the socket
$ 

Restore /etc/services after performing this test! Seriously!

from ntplib.

Yes, see above, the request method supports passing the port explicitly.

It's the first time in over 10 years since this library exists I see an environment which doesn't define the ntp service.

from ntplib.

I've changed the code to use port 123 instead of "ntp" to avoid issues in such environments.

@mahtin
I do not appreciate your tone.
The issue was obvious, which is why I asked the OP to test with socket.getservbyname("ntp") before making the change.
Your snarky comments do not bring anything to the conversation, so please refrain from them.

from ntplib.

An absolute apology for anything misunderstood - I was in no way meaning to be snarky. If you meant when I said "but is kinda ugly", then trust me that that's a reference to the underlying libraries socket.gaierror name/error value, not your code. Your code, as others also believe, is damn useful and excellent code.

Plus, as you said, services not resolving is a very rare issue.

Apologies again.

from ntplib.

No worries then - it's unfortunately easy to mis-communicate online.

Cheers!

from ntplib.