repoze.debug 0.7

Installation

Install using setuptools, e.g. (within a virtualenv):

$ easy_install repoze.debug

Configuration via Python

Wire up the middleware in your application:

from repoze.debug.responselogger import ResponseLoggingMiddleware
from logging import getLogger
middleware = ResponseLoggingMiddleware(
               app,
               max_bodylen=3072,
               keep=100,
               verbose_logger=getLogger('foo'),
               trace_logger = getLogger('bar'),
              )

The configuration options are as follows:

- ``max_bodylen`` should be the max size in bytes of the response
  body that should be logged.

- ``keep`` is the number of request entries to keep around in memory
  to service the GUI.

- ``verbose_logger`` is a PEP 282 logger instance (any).

- ``trace_logger`` is a PEP 282 logger instance (any).

Configuration via Paste

Wire the middleware into a pipeline in your Paste configuration, for example:

[filter:responselogger]
use = egg:repoze.debug#responselogger
verbose_log = %(here)s/response.log
trace_log = %(here)s/trace.log
# if max_bodylen is unset or is 0, it means do not limit body logging
# default is 3KB
max_bodylen = 3KB
# if max_logsize is unset or is 0, it means do not limit logsize; default is
# 100MB
max_logsize = 100MB
# if backup_count is 0, do not rotate the logfile.  Default is 10.
backup_count = 10
# "keep" is the the number of entries to keep around to show in the
# GUI. If keep is 0, no entries are kept (keeping entries around
# to show in the UI may be a security issue, as access to the GUI
# isn't authenticated)
keep = 100
...

[pipeline:main]
pipeline = egg:Paste#cgitb
           responselogger
           myapp

The middleware will log verbose response data to response.log and will log trace data to trace.log.

Debug UI

If you visit the path /__repoze.debug/static/debugui.html in your browser against a WSGI server that has the responselogger middleware in the main pipeline, you will see a paned debug interface much like http://static.repoze.org/misc/repoze-debug1.png . Here you can view recent requests and responses via this UI (as many request/response pairs are kept around as “keep” is set to in the config).

Verbose logger

Once the middleware is in the pipeline, it will log human-readable information about requests and responses to the verbose logger. An example of the verbose log output for a request follows:

--- begin REQUEST for 5930704 at Mon Jun 30 13:37:51 2008 ---
URL: GET http://127.0.0.1:9971/favicon.ico
CGI Variables
  ACTUAL_SERVER_PROTOCOL: HTTP/1.1
  HTTP_ACCEPT: */*
  HTTP_HOST: 127.0.0.1:9971
  HTTP_USER_AGENT: ApacheBench/2.0.40-dev
  PATH_INFO: /favicon.ico
  REMOTE_ADDR: 127.0.0.1
  REMOTE_PORT: 56527
  REQUEST_METHOD: GET
  SERVER_NAME: vitaminf-2.local
  SERVER_PORT: 9971
  SERVER_PROTOCOL: HTTP/1.0
  SERVER_SOFTWARE: CherryPy/3.0.2 WSGI Server
WSGI Variables
  application: <paste.httpexceptions.HTTPExceptionHandler object at 0x17c4b10>
  wsgi process: Multithreaded
--- end REQUEST for 5930704 ---

Each request is tagged with a (random) identifier. A response is also written to the verbose log, and can be matched up to the request that generated it via the identifier. If max_bodylen is specified and is nonzero, only the leading bytes of the body up to max_bodylen are logged, otherwise the entire body is logged. Here’s an example of a response in the log:

--- begin RESPONSE for 5930704 at Mon Jun 30 13:37:51 2008 ---
URL: GET http://127.0.0.1:9971/favicon.ico
Status: 200 OK
Response Headers
  Accept-Ranges: bytes
  Content-Length: 112
  Content-Type: application/octet-stream
  Last-Modified: Thu, 29 May 2008 23:47:57 GMT
Body:
^@^@^A^@^F^@^P^P^@^@^A^@ ^@h^D^@^@f^@^@^@^P^P^@^@^A^@^H^@h^E^@^@<CE>^D^@^@
^@^@^A^@ ^@<A8>^P^@^@6
Bodylen: 112
--- end RESPONSE for 5930704 (0.03 seconds) ---

Trace logger

The trace logger logs detailed debugging information about WSGI requests and responses. This logging can be turned on while the server is in production. It can then be postprocessed to help locate troublesome application code.

The format of a log message is:

{code} {pid} {request id} {time} {data}

Where:

{code} is B for begin, A for received output from the application,
E for finished sending output to the client.  A special code
exists, U, that is not really tied to any particular request.  It
is written to the log upon the first request after the server
is started.

{request id} is a unique request id.

{time} is the local time as seconds past the epoch.

{data} is the HTTP method and the URL for B, the HTTP status code
and the value of the content-length header for A, the actual
content length for E, and nothing for U.

For example:

U 91978 5930704 1214847471.97
B 91978 5930704 1214847471.97 GET http://127.0.0.1:9971/favicon.ico
B 91978 17963168 1214847471.97 GET http://127.0.0.1:9971/favicon.ico
A 91978 17963168 1214847471.99 200 112
A 91978 5930704 1214847471.99 200 112
E 91978 17963168 1214847471.99 112
E 91978 5930704 1214847471.99 112
B 91978 18022448 1214847472.0 GET http://127.0.0.1:9971/favicon.ico
A 91978 18022448 1214847472.01 200 112
B 91978 48634016 1214847472.01 GET http://127.0.0.1:9971/favicon.ico
E 91978 18022448 1214847472.01 112
B 91978 7805232 1214847472.01 GET http://127.0.0.1:9971/favicon.ico
A 91978 48634016 1214847472.01 200 112
E 91978 48634016 1214847472.01 112
A 91978 7805232 1214847472.02 200 112
E 91978 7805232 1214847472.02 112

This information is meant to be parsed with the included wsgirequestprofiler console script to help in debugging hangs or requests that take “too long”. Run the wsgirequestprofiler script with the –help flag for more information.

wsgirequestprofiler script

Usage::

bin/wsgirequestprofiler filename1 [filename2 …]

[–cumulative | –detailed | [–timed –resolution=seconds]] [–sort=spec] [–top=n] [–verbose] [–today | [–start=date] [–end=date] | –daysago=n ] [–writestats=filename | –readstats=filename] [–urlfocus=url] [–urlfocustime=seconds] [–help]

Provides a profile of one or more repoze.debug “trace” log files. Note that this script is a port of the Zope2 requestprofiler script (written originally in 2001!)

Reports are of four types: cumulative, detailed, timed, or urlfocus. The default is cumulative. Data is taken from one or more repoze.debug trace logs or from a preprocessed statistics file.

For cumulative reports, each line in the profile indicates information about a URL collected via a detailed request log.

For detailed reports, each line in the profile indicates information about a single request.

For timed reports, each line in the profile indicates informations about the number of requests and the number of requests/second for a period of time.

For urlfocus reports, ad-hoc information about requests surrounding the specified url is given.

Each filename is a path to a trace log that contains detailed request data. Multiple input files can be analyzed at the same time by providing the path to each file. (Analyzing multiple trace log files at once is useful if you have more than one machine running your application and you’d like to get an overview of all logs on those machines).

If you wish to make multiple analysis runs against the same input data, you may want to use the –writestats option. The –writestats option creates a file which holds preprocessed data representing the specfified input files. Subsequent runs (for example with a different sort spec) will be much faster if the –readstats option is used to specify a preprocessed stats file instead of actual input files because the logfile parse step is skipped.

If a sort value is specified, sort the profile info by the spec. The sort order is descending unless indicated. The default cumulative sort spec is total. The default detailed sort spec is start.

For cumulative reports, the following sort specs are accepted:

'hits'        -- the number of hits against the method
'hangs'       -- the number of unfinished requests to the method
'max'         -- the maximum time in secs taken by a request to this method
'min'         -- the minimum time in secs taken by a request to this method
'mean'        -- the mean time in secs taken by a request to this method
'median'      -- the median time in secs taken by a request to this method
'total'       -- the total time in secs across all requests to this method
'url'         -- the URL/method name (ascending)

For detailed (non-cumulative) reports, the following sort specs are accepted:

'start'       -- the start time of the request to repoze.debug (ascending)
'win'         -- the num of secs repoze.debug spent waiting for input
'wout'        -- the secs repoze.debug spent waiting for output from app
'wend'        -- the secs repoze.debug spent sending data to server
'total'       -- the secs taken for the request from begin to end
'endstage'    -- the last successfully completed request stage (B, I, A, E)
'osize'       -- the size in bytes of output provided by repoze.debug
'httpcode'    -- the HTTP response code provided by the app (ascending)
'active'      -- total num of requests pending at the end of this request
'url'         -- the URL  (ascending)

For timed and urlfocus reports, there are no sort specs allowed.

If the top argument is specified, only report on the top ‘n’ entries in the profile (as per the sort). The default is to show all data in the profile.

If the verbose argument is specified, do not trim url to fit into 80 cols.

If the today argument is specified, limit results to hits received today.

If the daysago argument is specified, limit results to hits received n days ago.

The resolution argument is used only for timed reports and specifies the number of seconds between consecutive lines in the report (default is 60 seconds).

The urlfocustime argument is used only for urlfocus reports and specifies the number of seconds to target before and after the URL provided in urlfocus mode. (default is 10 seconds).

If the start argument is specified in the form ‘DD/MM/YYYY HH:MM:SS’ (local time), limit results to hits received after this date/time.

If the end argument is specified in the form ‘DD/MM/YYYY HH:MM:SS’ (local time), limit results to hits received before this date/time.

start and end arguments are not honored when request stats are obtained via the --readstats argument.

Examples:

bin/wsgirequestprofiler debug.log

  Show cumulative report statistics for information in the file 'debug.log',
  by default sorted by 'total'.

bin/wsgirequestprofiler debug.log --detailed

  Show detailed report statistics sorted by 'start' (by default).

bin/wsgirequestprofiler debug.log debug2.log --detailed

  Show detailed report statistics for both logs sorted by 'start'
  (by default).

bin/wsgirequestprofiler debug.log --cumulative --sort=mean --today --verbose

  Show cumulative report statistics sorted by mean for entries in the log
  which happened today, and do not trim the URL in the resulting report.

bin/wsgirequestprofiler debug.log --cumulative --sort=mean --daysago=3 --verbose

  Show cumulative report statistics sorted by mean for entries in the log
  which happened three days ago, and do not trim the URL in the resulting report.

bin/wsgirequestprofiler debug.log --urlfocus='/manage_main' --urlfocustime=60

  Show 'urlfocus' report which displays statistics about requests
  surrounding the invocation of '/manage_main'.  Focus on the time periods
  60 seconds before and after each invocation of the '/manage_main' URL.

bin/wsgirequestprofiler debug.log --detailed --start='2001/05/10 06:00:00'
  --end='2001/05/11 23:00:00'

  Show detailed report statistics for entries in 'debug.log' which
  begin after 6am local time on May 10, 2001 and which end before
  11pm local time on May 11, 2001.

bin/wsgirequestprofiler debug.log --timed --resolution=300 --start='2001/05/10 06:00:00'
  --end='2001/05/11 23:00:00'

  Show timed report statistics for entries in the log for one day
  with a resolution of 5 minutes

bin/wsgirequestprofiler debug.log --top=100 --sort=max

  Show cumulative report of the the 'top' 100 methods sorted by maximum
  elapsed time.

bin/wsgirequestprofiler debug.log debug2.log --writestats='requests.stat'

  Write stats file for debug.log and debug2.log into 'requests.stat' and
  show default report.

bin/wsgirequestprofiler --readstats='requests.stat' --detailed

  Read from 'requests.stat' stats file (instead of actual -M log files)
  and show detailed report against this data.

Sample wsgirequestprofiler output

Sample output from wsgirequestprofiler trace.log:

Hangs  Hits    Total   Max   Min   Med  Mean URL
    0   848    88.58  2.14  0.02  0.10  0.10 http://127.0.0.1:9971/ehs
    0   737    73.24  1.45  0.02  0.10  0.10 http://127.0.0.1:9971/ehs/login_f
    0     2    13.83 12.41  1.42  6.92  6.92 http://localhost:9971/ehs/archive
    0     1     0.55  0.55  0.55  0.55  0.55 http://localhost:9971/ehs/archive
    0     1     0.49  0.49  0.49  0.49  0.49 http://localhost:9971/ehs/archive
    0     1     0.29  0.29  0.29  0.29  0.29 http://localhost:9971/ehs
    0     1     0.19  0.19  0.19  0.19  0.19 http://localhost:9971/ehs/archive
    0     1     0.13  0.13  0.13  0.13  0.13 http://localhost:9971/ehs/archive
    0     1     0.06  0.06  0.06  0.06  0.06 http://localhost:9971/ehs/archive
    0     1     0.06  0.06  0.06  0.06  0.06 http://localhost:9971/ehs/archive
    0     1     0.02  0.02  0.02  0.02  0.02 http://localhost:9971/empty.css
    0     1     0.01  0.01  0.01  0.01  0.01 http://localhost:9971/ehs/archive
    0     1     0.01  0.01  0.01  0.01  0.01 http://localhost:9971/ehs/ehn_alt

Configuration via Python

Wire up the middleware in your application:

from repoze.debug.canary import CanaryMiddleware
middleware = CanaryMiddleware(app)

Configuration via Paste

Wire the canary middleware up into your pipeline:

[pipeline:main]
pipeline = egg:Paste#cgitb
           egg:repoze.debug#canary
           myapp

Usage

If refcounts to repoze.debug.canary.Canary grow without bound, you know you are leaking WSGI environment dictionaries. Use e.g. Dozer to find reference leaks.

Configuration via Python

Wire up the middleware in your application:

from repoze.debug.pdbpm import PostMortemDebug
middleware = PostMortemDebug(app)

Configuration via Paste

Use the ‘egg:repoze.debug#pdbpm’ entry point in your Paste configuration, eg.:

[pipeline:main]
pipeline = egg:Paste#cgitb
           egg:repoze.debug#pdbpm
           myapp

By default, HTTP exceptions from the paste.httpexceptions are ignored. This may be disabled using the ignore_http_exceptions flag (set to False).

Configuration via Python

Wire up the middleware in your application:

from repoze.debug.threads import MonitoringMiddleware
middleware = MonitoringMiddleware(app)

Configuration via Paste

Use the ‘egg:repoze.debug#threads’ entry point in your Paste configuration, eg.:

[pipeline:main]
pipeline = egg:Paste#cgitb
           egg:repoze.debug#threads
           myapp

The middleware accepts no configuration parameters.

0.7 (2009/09/06)

• The iterator returned by an application was closed too soon when using the responselogger middleware, resulting in, e.g. errors from paste.fileapp complaining about “file already closed”.

• If the keep parameter in the “responselogger” middleware is set to zero, no entries are logged (not even one, as previously may have happened).

• Better test coverage.

• Ignore HTTP errors in post-mortem debug middleware. The exceptions we want to catch here are application-level. A configuration option has been added to keep the old behavior.

• Added middleware “threads” to debug threads (based on an adaptation of Florent Guillaume’s “DeadlockDebugger” product for Zope 2).

0.6.2 (2008/07/03)

• Show a “short” URL in the debug UI.

0.6.1 (2008/07/03)

• Fix debug UI bug: show escaped body regardless of content-type.

0.6 (2008/07/02)

• Fix logging bug. Symptom: AttributeError: ‘NoneType’ object has no attribute ‘info’

0.5 (2008/06/30)

• Make debug request id reflect approximate UNIX time rather than a random debug id.

• Deal with responses via a generator; don’t unwind response bodies into memory.

• Default max_bodysize is now 3K rather than the entire response body.

• User interface; keep entries around to show in GUI. See /__repoze.debug/static/debugui.html.

• We now write two logs: a verbose log, and a trace log. The verbose log contains information about headers, request information, response bodies, etc. The trace log is more compact and is written in essence to be parsed by a tool.

• The ‘filename’ option in Paste config is now ‘verbose_log’.

• Port Zope’s ‘requestprofiler’ script to WSGI. Invoke via ‘wsgirequestprofiler’ to see help; operates against ‘trace’ log.

0.4 (2008/06/25)

• Add pdbpm middleware for dropping into the post-mortem debugger upon an exception (copied from repoze.errorlog).

0.3 (2008/06/25)

• Add ‘canary’ middleware for detecting environment dictionary leaks. Add to your Paste config via ‘egg:repoze.debug#canary’; it takes no arguments. If refcounts to repoze.debug.canary.Canary grow without bound, you know you are leaking WSGI environment dictionaries.

• Add source url to response logging.

0.2 (2008/06/14)

• Add warning if content-length != body length.

0.1 (2008/06/13)

• Initial release.