compose/fig/cli/log_printer.py

64 lines
1.8 KiB
Python

from __future__ import unicode_literals
from __future__ import absolute_import
import sys
from itertools import cycle
from .multiplexer import Multiplexer
from . import colors
class LogPrinter(object):
def __init__(self, containers, attach_params=None):
self.containers = containers
self.attach_params = attach_params or {}
self.generators = self._make_log_generators()
def run(self):
mux = Multiplexer(self.generators)
for line in mux.loop():
sys.stdout.write(line)
def _make_log_generators(self):
color_fns = cycle(colors.rainbow())
generators = []
for container in self.containers:
color_fn = color_fns.next()
generators.append(self._make_log_generator(container, color_fn))
return generators
def _make_log_generator(self, container, color_fn):
prefix = color_fn(container.name + " | ")
for line in split_buffer(self._attach(container), '\n'):
yield prefix + line
def _attach(self, container):
params = {
'stdout': True,
'stderr': True,
'stream': True,
}
params.update(self.attach_params)
params = dict((name, 1 if value else 0) for (name, value) in list(params.items()))
return container.attach(**params)
def split_buffer(reader, separator):
"""
Given a generator which yields strings and a separator string,
joins all input, splits on the separator and yields each chunk.
Requires that each input string is decodable as UTF-8.
"""
buffered = ''
for data in reader:
lines = (buffered + data.decode('utf-8')).split(separator)
for line in lines[:-1]:
yield line + separator
if len(lines) > 1:
buffered = lines[-1]
if len(buffered) > 0:
yield buffered