#!/usr/bin/python
#
# Copyright (c) 2013 IBM Corp.
#
# 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 cgi
import fileinput
import os.path
import re
import sys
import wsgiref.util
DATEFMT = '\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}(\.\d{3})?'
STATUSFMT = '(DEBUG|INFO|WARN|ERROR|TRACE|AUDIT)'
LOGMATCH = '(?P<date>%s)(?P<pid> \d+)? (?P<status>%s)' % (DATEFMT, STATUSFMT)
def _html_close():
return ("</span></pre></body></html>\n")
def _css_preamble():
"""Write a valid html start with css that we need."""
return ("""<html>
<head>
<style>
a {color: #000; text-decoration: none}
a:hover {text-decoration: underline}
.DEBUG, .DEBUG a {color: #888}
.ERROR, .ERROR a {color: #c00; font-weight: bold}
.TRACE, .TRACE a {color: #c60}
.WARN, .WARN a {color: #D89100; font-weight: bold}
.INFO, .INFO a {color: #006; font-weight: bold}
</style>
<body><pre><span>\n""")
def color_by_sev(line):
"""Wrap a line in a span whose class matches it's severity."""
m = re.match(LOGMATCH, line)
if m:
return "<span class='%s'>%s</span>" % (m.group('status'), line)
else:
return line
def escape_html(line):
"""Escape the html in a line.
We need to do this because we dump xml into the logs, and if we don't
escape the xml we end up with invisible parts of the logs in turning it
into html.
"""
return cgi.escape(line)
def link_timestamp(line):
m = re.match(
'(<span class=\'(?P<class>[^\']+)\'>)?(?P<date>%s)(?P<rest>.*)' % DATEFMT,
line)
if m:
date = "_" + re.sub('[\s\:\.]', '_', m.group('date'))
return "</span><span class='%s %s'><a name='%s' class='date' href='#%s'>%s</a>%s\n" % (
m.group('class'), date, date, date, m.group('date'), m.group('rest'))
else:
return line
def passthrough_filter(fname):
for line in fileinput.input(fname, openhook=fileinput.hook_compressed):
yield line
def html_filter(fname):
"""Generator to read logs and output html in a stream.
This produces a stream of the htmlified logs which lets us return
data quickly to the user, and use minimal memory in the process.
"""
yield _css_preamble()
for line in fileinput.input(fname, openhook=fileinput.hook_compressed):
newline = escape_html(line)
newline = color_by_sev(newline)
newline = link_timestamp(newline)
yield newline
yield _html_close()
def htmlify_stdin():
out = sys.stdout
out.write(_css_preamble())
for line in fileinput.input():
newline = escape_html(line)
newline = color_by_sev(newline)
newline = link_timestamp(newline)
out.write(newline)
out.write(_html_close())
def safe_path(root, environ):
"""Pull out a safe path from a url.
Basically we need to ensure that the final computed path
remains under the root path. If not, we return None to indicate
that we are very sad.
"""
path = wsgiref.util.request_uri(environ)
match = re.search('htmlify/(.*)', path)
raw = match.groups(1)[0]
newpath = os.path.abspath(os.path.join(root, raw))
if newpath.find(root) == 0:
return newpath
else:
return None
def should_be_html(environ):
"""Simple content negotiation."""
return 'HTTP_ACCEPT' in environ and 'text/html' in environ['HTTP_ACCEPT']
def application(environ, start_response):
status = '200 OK'
logpath = safe_path('/srv/static/logs/', environ)
if not logpath:
status = '400 Bad Request'
response_headers = [('Content-type', 'text/plain')]
start_response(status, response_headers)
return ['Invalid file url']
try:
if should_be_html(environ):
response_headers = [('Content-type', 'text/html')]
generator = html_filter(logpath)
start_response(status, response_headers)
return generator
else:
response_headers = [('Content-type', 'text/plain')]
generator = passthrough_filter(logpath)
start_response(status, response_headers)
return generator
except IOError:
status = "404 Not Found"
response_headers = [('Content-type', 'text/plain')]
start_response(status, response_headers)
return ['File Not Found']
# for development purposes, makes it easy to test the filter output
if __name__ == "__main__":
htmlify_stdin()