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#!/usr/bin/env python2.7
# Copyright 2015 gRPC authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import argparse
import subprocess
import os
import tempfile
import sys
import time
import signal
import yaml
argp = argparse.ArgumentParser(description='Runs a DNS server for LB interop tests')
argp.add_argument('-l', '--grpclb_ips', default=None, type=str,
help='Comma-separated list of IP addresses of balancers')
argp.add_argument('-f', '--fallback_ips', default=None, type=str,
help='Comma-separated list of IP addresses of fallback servers')
argp.add_argument('-c', '--cause_no_error_no_data_for_balancer_a_record',
default=False, action='store_const', const=True,
help=('Used for testing the case in which the grpclb '
'balancer A record lookup results in a DNS NOERROR response '
'but with no ANSWER section i.e. no addresses'))
args = argp.parse_args()
balancer_records = []
grpclb_ips = args.grpclb_ips.split(',')
if grpclb_ips[0]:
for ip in grpclb_ips:
balancer_records.append({
'TTL': '2100',
'data': ip,
'type': 'A',
})
fallback_records = []
fallback_ips = args.fallback_ips.split(',')
if fallback_ips[0]:
for ip in fallback_ips:
fallback_records.append({
'TTL': '2100',
'data': ip,
'type': 'A',
})
records_config_yaml = {
'resolver_tests_common_zone_name':
'test.google.fr.',
'resolver_component_tests': [{
'records': {
'_grpclb._tcp.server': [
{
'TTL': '2100',
'data': '0 0 12000 balancer',
'type': 'SRV'
},
],
'balancer':
balancer_records,
'server':
fallback_records,
}
}]
}
if args.cause_no_error_no_data_for_balancer_a_record:
balancer_records = records_config_yaml[
'resolver_component_tests'][0]['records']['balancer']
assert not balancer_records
# Insert a TXT record at the balancer.test.google.fr. domain.
# This TXT record won't actually be resolved or used by gRPC clients;
# inserting this record is just a way get the balancer.test.google.fr.
# A record queries to return NOERROR DNS responses that also have no
# ANSWER section, in order to simulate this failure case.
balancer_records.append({
'TTL': '2100',
'data': 'arbitrary string that wont actually be resolved',
'type': 'TXT',
})
# Generate the actual DNS server records config file
records_config_path = tempfile.mktemp()
with open(records_config_path, 'w') as records_config_generated:
records_config_generated.write(yaml.dump(records_config_yaml))
with open(records_config_path, 'r') as records_config_generated:
sys.stderr.write('===== DNS server records config: =====\n')
sys.stderr.write(records_config_generated.read())
sys.stderr.write('======================================\n')
# Run the DNS server
# Note that we need to add the extra
# A record for metadata.google.internal in order for compute engine
# OAuth creds and ALTS creds to work.
# TODO(apolcyn): should metadata.google.internal always resolve
# to 169.254.169.254?
subprocess.check_output([
'/var/local/git/grpc/test/cpp/naming/utils/dns_server.py', '--port=53',
'--records_config_path', records_config_path,
'--add_a_record=metadata.google.internal:169.254.169.254',
])
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