Clean up C++ client curl configuration

[michaeljmarshall]

Motivation

Clean up C++ client curl configuration.

Modifications

• Remove some settings

Verifying this change

This is a minor change with well known scope. No additional tests are required.

• doc-not-needed

[dave2wave]

LGTM

[BewareMyPower]

Could you explain the motivation of this PR? The default values of these two configs are 1, which enables strict certificates check. I think it was zero are just to disable the check.

We observed an error like:

2022-10-20 02:42:38.545 ERROR [140011702527744] AuthOauth2:223 | Response failed for getting the well-known configuration <xxx>. Error Code 77: error setting certificate verify locations:
  CAfile: /etc/pki/tls/certs/ca-bundle.crt
  CApath: none

It seems to be related to this PR, see https://curl.se/libcurl/c/CURLOPT_SSL_VERIFYPEER.html

This trust is based on a chain of digital signatures, rooted in certification authority (CA) certificates you supply. curl uses a default bundle of CA certificates (the path for that is determined at build time)

/cc @freeznet @jiangpengcheng

[BewareMyPower]

I have confirmed it's caused by this PR and will revert it from branch-2.7 to 2.11. Though we should encourage users to use new separated pulsar-client-cpp and pulsar-client-python repos, I will confirm again for these new repos.

Reproduce

Checkout branch-2.9, run the following command.

$ pulsar-client-cpp/docker/build-wheels.sh 3.8 cp38-cp38 manylinux2014 x86_64

Then pulsar_client-2.9.3-cp38-cp38-linux_x86_64.whl will be generated under pulsar-client-cpp/python/dist. Then install the wheel in a ubuntu:20.04 container.

docker run -v $PWD:/pulsar -it ubuntu:20.04 /bin/bash

apt update -y
apt install -y python3 python3-pip
pip3 install /pulsar/pulsar-client-cpp/python/dist/pulsar_client-2.9.3-cp38-cp38-linux_x86_64.whl

Then run the following script:

#!/usr/bin/env python3
from pulsar import AuthenticationOauth2

auth = AuthenticationOauth2(auth_params_string='''{
    "type": "client_credentials",
    "issuer_url": "https://dev-kt-aa9ne.us.auth0.com",
    "client_id": "xxx",
    "client_secret": "xxx"
}''')

Output:

2022-11-02 09:28:19.003 ERROR [140425586124608] AuthOauth2:222 | Response failed for getting the well-known configuration https://dev-kt-aa9ne.us.auth0.com. Error Code 77: error setting certificate verify locations:
  CAfile: /etc/pki/tls/certs/ca-bundle.crt
  CApath: none

After I reverted this PR, it works.

/cc @michaeljmarshall @merlimat @dave2wave @freeznet @jiangpengcheng @mattisonchao

[michaeljmarshall]

@BewareMyPower - this should not have been reverted. Please see this stack overflow for help solving your environment's issue: https://stackoverflow.com/questions/3160909/how-do-i-deal-with-certificates-using-curl-while-trying-to-access-an-https-url.

[BewareMyPower]

They are restored now. I will confirm the solution soon.

[michaeljmarshall]

Thanks @BewareMyPower.