Files
container.training/link-to-ambassadors.py
2015-10-05 08:50:48 -07:00

63 lines
2.1 KiB
Python
Executable File

#!/usr/bin/env python
import os
import sys
import yaml
# You can specify up to 2 parameters:
# - with 0 parameter, we will look for the COMPOSE_FILE env var
# - with 1 parameter, the same file will be used for in and out
# - with 2 parameters, the 1st is the input, the 2nd the output
if len(sys.argv)==1:
if "COMPOSE_FILE" not in os.environ:
print("Please specify 1 or 2 file names, or set COMPOSE_FILE.")
sys.exit(1)
compose_file = os.environ["COMPOSE_FILE"]
if compose_file == "docker-compose.yml":
print("Refusing to operate directly on docker-compose.yml.")
print("Specify it on the command-line if that's what you want.")
sys.exit(1)
input_file, output_file = compose_file, compose_file
elif len(sys.argv)==2:
input_file, output_file = sys.argv[1], sys.argv[1]
elif len(sys.argv)==3:
input_file, output_file = sys.argv[1], sys.argv[2]
else:
print("Too many arguments. Please specify up to 2 file names.")
sys.exit(1)
stack = yaml.load(open(input_file))
# The ambassadors need to know the service port to use.
# Those ports must be declared here.
ports = yaml.load(open("ports.yml"))
def generate_local_addr():
last_byte = 2
while last_byte<255:
yield "127.127.0.{}".format(last_byte)
last_byte += 1
for service_name, service in stack.items():
if "links" in service:
for link, local_addr in zip(service["links"], generate_local_addr()):
if link not in ports:
print("Skipping link {} in service {} "
"(no port mapping defined). "
"Your code will probably break."
.format(link, service_name))
continue
if "extra_hosts" not in service:
service["extra_hosts"] = {}
service["extra_hosts"][link] = local_addr
del service["links"]
if "ports" in service:
del service["ports"]
if "volumes" in service:
del service["volumes"]
if service_name in ports:
service["ports"] = [ ports[service_name] ]
yaml.safe_dump(stack, open(output_file, "w"), default_flow_style=False)