supervisor/CHANGES.txt

Next Release

  - 3.0a3 broke Python 2.3 backwards compatibility.

  - On Debian Sarge, one user reported that a call to
    options.mktempfile would fail with an "[Errno 9] Bad file
    descriptor" at supervisord startup time.  I was unable to
    reproduce this, but we found a workaround that seemed to work for
    him and it's included in this release.  See
    http://www.plope.com/software/collector/252 for more information.
    Thanks to William Dode.

  - The fault ALREADY_TERMINATED has been removed.  It was only 
    raised by supervisor.sendProcessStdin().  That method now returns 
    NOT_RUNNING for parity with the other methods. (Mike Naberezny)

  - The fault TIMED_OUT has been removed.  It was not used.

  - Supervisor now depends on meld3 0.6.4, which does not compile its
    C extensions by default, so there is no more need to faff around
    with NO_MELD3_EXTENSION_MODULES during installation if you don't
    have a C compiler or the Python development libraries on your
    system.

  - Instead of making a user root around for the sample.conf file,
    provide a convenience command "echo_supervisord_conf", which he can
    use to echo the sample.conf to his terminal (and redirect to a file 
    appropriately).  This is a new user convenience (especially one who
    has no Python experience).

  - Added 'numprocs_start' config option to '[program:x]' and
    '[eventlistener:x]' sections.  This is an offset used to compute
    the first integer that 'numprocs' will begin to start from.
    Contributed by Antonio Beamud Montero.

  - Added capability for '[include]' config section to config format.
    This section must contain a single key "files", which must name a
    space-separated list of file globs that will be included in
    supervisor's configuration.  Contributed by Ian Bicking.

  - Invoking the 'reload' supervisorctl command could trigger a bug in
    supervisord which caused it to crash.  See
    http://www.plope.com/software/collector/253 .  Thanks to William
    Dode for a bug report.

  - The 'pidproxy' script was made into a console script.

  - The 'password' value in both the '[inet_http_server]' and
    '[unix_http_server]' sections can now optionally be specified as a
    SHA hexdigest instead of as cleartext.  Values prefixed with
    '{SHA}' will be considered SHA hex digests.  To encrypt a password
    to a form suitable for pasting into the configuration file using
    Python, do, e.g.:

       >>> import sha
       >>> '{SHA}' + sha.new('thepassword').hexdigest()
       '{SHA}82ab876d1387bfafe46cc1c8a2ef074eae50cb1d'

  - The subtypes of the events PROCESS_STATE_CHANGE (and
    PROCESS_STATE_CHANGE itself) have been removed, replaced with a
    simpler set of PROCESS_STATE subscribable event types.

    The new event types are:

      PROCESS_STATE_STOPPED
      PROCESS_STATE_EXITED
      PROCESS_STATE_STARTING
      PROCESS_STATE_STOPPING
      PROCESS_STATE_BACKOFF
      PROCESS_STATE_FATAL
      PROCESS_STATE_RUNNING
      PROCESS_STATE_UNKNOWN
      PROCESS_STATE # abstract

    PROCESS_STATE_STARTING replaces:

      PROCESS_STATE_CHANGE_STARTING_FROM_STOPPED
      PROCESS_STATE_CHANGE_STARTING_FROM_BACKOFF
      PROCESS_STATE_CHANGE_STARTING_FROM_EXITED
      PROCESS_STATE_CHANGE_STARTING_FROM_FATAL

    PROCESS_STATE_RUNNING replaces
    PROCESS_STATE_CHANGE_RUNNING_FROM_STARTED

    PROCESS_STATE_BACKOFF replaces
    PROCESS_STATE_CHANGE_BACKOFF_FROM_STARTING

    PROCESS_STATE_STOPPING replaces:

      PROCESS_STATE_CHANGE_STOPPING_FROM_RUNNING
      PROCESS_STATE_CHANGE_STOPPING_FROM_STARTING

    PROCESS_STATE_EXITED replaces
    PROCESS_STATE_CHANGE_EXITED_FROM_RUNNING

    PROCESS_STATE_STOPPED replaces
    PROCESS_STATE_CHANGE_STOPPED_FROM_STOPPING

    PROCESS_STATE_FATAL replaces
    PROCESS_STATE_CHANGE_FATAL_FROM_BACKOFF

    PROCESS_STATE_UNKNOWN replaces PROCESS_STATE_CHANGE_TO_UNKNOWN

    PROCESS_STATE replaces PROCESS_STATE_CHANGE

    The PROCESS_STATE_CHANGE_EXITED_OR_STOPPED abstract event is gone.

    All process state changes have at least "processname",
    "groupname", and "from_state" (the name of the previous state) in
    their serializations.

    PROCESS_STATE_EXITED additionaly has "expected" (1 or 0) and "pid"
    (the process id) in its serialization.

    PROCESS_STATE_RUNNING, PROCESS_STATE_STOPPING,
    PROCESS_STATE_STOPPED additionally have "pid" in their
    serializations.

    PROCESS_STATE_STARTING and PROCESS_STATE_BACKOFF have "tries" in
    their serialization (initially "0", bumped +1 each time a start
    retry happens).

  - Remove documentation from README.txt, point people to
    http://supervisord.org/manual/ .

  - The eventlistener request/response protocol has changed.  OK/FAIL
    must now be wrapped in a RESULT envelope so we can use it for more
    specialized communications.

    Previously, to signify success, an event listener would write the
    string 'OK\n' to its stdout.  To signify that the event was seen
    but couldn't be handled by the listener and should be rebuffered,
    an event listener would write the string 'FAIL\n' to its stdout.

    In the new protocol, the listener must write the string:

      RESULT {resultlen}\n{result}

    For example, to signify OK:

      RESULT 2\nOK

    To signify FAIL:

      RESULT 4\nFAIL

    See the scripts/sample_eventlistener.py script for an example.

  - To provide a hook point for custom results returned from event
    handlers (see above) the [eventlistener:x] configuration sections
    now accept a "result_handler=" parameter,
    e.g. "result_handler=supervisor.dispatchers:default_handler" (the
    default) or "handler=mypackage:myhandler".  The keys are pkgutil
    "entry point" specifications (importable Python function names).
    Result handlers must be callables which accept two arguments: one
    named "event" which represents the event, and the other named
    "result", which represents the listener's result.  A result
    handler either executes successfully or raises an exception.  If
    it raises a supervisor.dispatchers.RejectEvent exception, the
    event will be rebuffered, and the eventhandler will be placed back
    into the ACKNOWLEDGED state.  If it raises any other exception,
    the event handler will be placed in the UNKNOWN state.  If it does
    not raise any exception, the event is considered successfully
    processed.  A result handler's return value is ignored.  Writing a
    result handler is a "in case of emergency break glass" sort of
    thing, it is not something to be used for arbitrary business code.
    In particular, handlers *must not block* for any appreciable
    amount of time.

    The 'standard' eventlistener result handler
    (supervisor.dispatchers:default_handler) does nothing if it
    receives an "OK" and will raise a
    supervisor.dispatchers.RejectEvent exception if it receives any
    other value.

  - Supervisord now emits TICK events, which happen every N seconds.
    Three types of TICK events are available: TICK_5 (every five
    seconds), TICK_60 (every minute), TICK_3600 (every hour).  Event
    listeners may subscribe to one of these types of events to perform
    every-so-often processing.  TICK events are subtypes of the EVENT
    type.

 - Get rid of OSX platform-specific memory monitor and replace with
   memmon.py, which works on both Linux and Mac OS.

3.0a3

  - Supervisorctl now reports a better error message when the main
    supervisor XML-RPC namespace is not registered.  Thanks to
    Mike Orr for reporting this. (Mike Naberezny)

  - Create 'scripts' directory within supervisor package, move
    'pidproxy.py' there, and place sample event listener and comm
    event programs within the directory.

  - When an event notification is buffered (either because a listener
    rejected it or because all listeners were busy when we attempted
    to send it originally), we now rebuffer it in a way that will
    result in it being retried earlier than it used to be.

  - When a listener process exits (unexpectedly) before transitioning
    from the BUSY state, rebuffer the event that was being processed.

  - supervisorctl 'tail' command now accepts a trailing specifier:
    'stderr' or 'stdout', which respectively, allow a user to tail the
    stderr or stdout of the named process.  When this specifier is not
    provided, tail defaults to stdout.

  - supervisor 'clear' command now clears both stderr and stdout logs
    for the given process.

  - When a process encounters a spawn error as a result of a failed
    execve or when it cannot setuid to a given uid, it now puts this
    info into the process' stderr log rather than its stdout log.

  - The event listener protocol header now contains the 'server'
    identifier, the 'pool' that the event emanated from, and the
    'poolserial' as well as the values it previously contained
    (version, event name, serial, and length).  The server identifier
    is taken from the config file options value 'identifier', the
    'pool' value is the name of the listener pool that this event
    emanates from, and the 'poolserial' is a serial number assigned to
    the event local to the pool that is processing it.

  - The event listener protocol header is now a sequence of key-value
    pairs rather than a list of positional values.  Previously, a
    representative header looked like:

      SUPERVISOR3.0 PROCESS_COMMUNICATION_STDOUT 30 22\n

    Now it looks like:

      ver:3.0 server:supervisor serial:21 ... 

  - Specific event payload serializations have changed.  All event
    types that deal with processes now include the pid of the process
    that the event is describing.  In event serialization "header"
    values, we've removed the space between the header name and the
    value and headers are now separated by a space instead of a line
    feed.  The names of keys in all event types have had underscores
    removed.

  - Abandon the use of the Python stdlib 'logging' module for speed
    and cleanliness purposes.  We've rolled our own.

  - Fix crash on start if AUTO logging is used with a max_bytes of
    zero for a process.

  - Improve process communication event performance.

  - The process config parameters 'stdout_capturefile' and
    'stderr_capturefile' are no longer valid.  They have been replaced
    with the 'stdout_capture_maxbytes' and 'stderr_capture_maxbytes'
    parameters, which are meant to be suffix-multiplied integers.
    They both default to zero.  When they are zero, process
    communication event capturing is not performed.  When either is
    nonzero, the value represents the maximum number of bytes that
    will be captured between process event start and end tags.  This
    change was to support the fact that we no longer keep capture data
    in a separate file, we just use a FIFO in RAM to maintain capture
    info.  For users whom don't care about process communication
    events, or whom haven't changed the defaults for
    'stdout_capturefile' or 'stderr_capturefile', they needn't do
    anything to their configurations to deal with this change.

  - Log message levels have been normalized.  In particular, process
    stdin/stdout is now logged at 'debug' level rather than at 'trace'
    level ('trace' level is now reserved for output useful typically
    for debugging supervisor itself).  See 'Supervisor Log Levels' in
    README.txt for more info.

  - When an event is rebuffered (because all listeners are busy or a
    listener rejected the event), the rebuffered event is now inserted
    in the head of the listener event queue.  This doesn't guarantee
    event emission in natural ordering, because if a listener rejects
    an event or dies while it's processing an event, it can take an
    arbitrary amount of time for the event to be rebuffered, and other
    events may be processed in the meantime.  But if pool listeners
    never reject an event or don't die while processing an event, this
    guarantees that events will be emitted in the order that they were
    received because if all listeners are busy, the rebuffered event
    will be tried again "first" on the next go-around.

  - Removed EVENT_BUFFER_OVERFLOW event type.

  - The supervisorctl xmlrpc proxy can now communicate with
    supervisord using a persistent HTTP connection.

  - A new module "supervisor.childutils" was added.  This module
    provides utilities for Python scripts which act as children of
    supervisord.  Most notably, it contains an API method
    "getRPCInterface" allows you to obtain an xmlrpxlib ServerProxy
    that is willing to communicate with the parent supervisor.  It
    also contains utility functions that allow for parsing of
    supervisor event listener protocol headers.  A pair of scripts
    (loop_eventgen.py and loop_listener.py) were added to the script
    directory that serve as examples about how to use the childutils
    module.

  - A new envvar is added to child process environments:
    SUPERVISOR_SERVER_URL.  This contains the server URL for the
    supervisord running the child.

  - An 'OK' URL was added at /ok.html which just returns the string
    'OK' (can be used for up checks or speed checks via
    plain-old-HTTP).

  - An additional command-line option '--profile_options' is accepted
    by the supervisord script for developer use.

      supervisord -n -c sample.conf --profile_options=cumulative,calls

    The values are sort_stats options that can be passed to the
    standard Python profiler's PStats sort_stats method.

    When you exit supervisor, it will print Python profiling output to
    stdout.

  - If cElementTree is installed in the Python used to invoke
    supervisor, an alternate (faster, by about 2X) XML parser will be
    used to parse XML-RPC request bodies.  cElementTree was added as
    an "extras_require" option in setup.py.

  - Added the ability to start, stop, and restart process groups to
    supervisorctl.  To start a group, use "start groupname:*".  To
    start multiple groups, use "start groupname1:* groupname2:*".
    Equivalent commands work for "stop" and "restart". You can mix and
    match short processnames, fullly-specified group:process names,
    and groupsplats on the same line for any of these commands.

  - Added 'directory' option to process config.  If you set this
    option, supervisor will chdir to this directory before executing
    the child program (and thus it will be the child's cwd).

  - Added 'umask' option to process config.  If you set this option,
    supervisor will set the umask of the child program.  (Thanks to
    Ian Bicking for the suggestion).

  - A pair of scripts "osx_memmon_eventgen.py" and
    "osx_memmon_listener.py" have been added to the scripts directory.
    If they are used together as described in their comments,
    processes which are consuming "too much" memory will be restarted.
    The 'eventgen' script only works on OSX (my main development
    platform) but it should be trivially generalizable to other
    operating systems.

  - The long form "--configuration" (-c) command line option for
    supervisord was broken.  Reported by Mike Orr.  (Mike Naberezny)

  - New log level: BLAT (blather).  We log all
    supervisor-internal-related debugging info here.  Thanks to Mike
    Orr for the suggestion.

  - We now allow supervisor to listen on both a UNIX domain socket and
    an inet socket instead of making them mutually exclusive.  As a
    result, the options "http_port", "http_username", "http_password",
    "sockchmod" and "sockchown" are no longer part of the
    '[supervisord]' section configuration. These have been supplanted
    by two other sections: '[unix_http_server]' and
    '[inet_http_server'].  You'll need to insert one or the other
    (depending on whether you want to listen on a UNIX domain socket
    or a TCP socket respectively) or both into your supervisord.conf
    file.  These sections have their own options (where applicable)
    for port, username, password, chmod, and chown.  See README.txt
    for more information about these sections.

  - All supervisord command-line options related to "http_port",
    "http_username", "http_password", "sockchmod" and "sockchown" have
    been removed (see above point for rationale).

  - The option that *used* to be 'sockchown' within the
    '[supervisord]' section (and is now named 'chown' within the
    '[unix_http_server]' section) used to accept a dot-separated
    user.group value.  The separator now must be a colon ":",
    e.g. "user:group".  Unices allow for dots in usernames, so this
    change is a bugfix.  Thanks to Ian Bicking for the bug report.

  - If a '-c' option is not specified on the command line, both
    supervisord and supervisorctl will search for one in the paths
    './supervisord.conf' , './etc/supervisord.conf' (relative to the
    current working dir when supervisord or supervisorctl is invoked)
    or in '/etc/supervisord.conf' (the old default path).  These paths
    are searched in order, and supervisord and supervisorctl will use
    the first one found.  If none are found, supervisor will fail to
    start.

  - The Python string expression '%(here)s' (referring to the
    directory in which the the configuration file was found) can be
    used within the following sections/options within the config file:

        unix_http_server:file
        supervisor:directory
        supervisor:logfile
        supervisor:pidfile
        supervisor:childlogdir
        supervisor:environment
        program:environment
        program:stdout_logfile
        program:stderr_logfile
        program:process_name
        program:command

  - The '--environment' aka '-b' option was removed from the list of
    available command-line switches to supervisord (use "A=1 B=2
    bin/supervisord" instead).

  - If the socket filename (the tail-end of the unix:// URL) was
    longer than 64 characters, supervisorctl would fail with an
    encoding error at startup.

  - The 'identifier' command-line argument was not functional.

  - Fixed http://www.plope.com/software/collector/215 (bad error
    message in supervisorctl when program command not found on PATH).

  - Some child processes may not have been shut down properly at
    supervisor shutdown time.

  - Move to ZPL-derived (but not ZPL) license availble from
    http://www.repoze.org/LICENSE.txt; it's slightly less restrictive
    than the ZPL (no servicemark clause).

  - Spurious errors related to unclosed files ("bad file descriptor",
    typically) were evident at supervisord "reload" time (when using
    the "reload" command from supervisorctl).

  - Updated ez_setup.py to one that knows about setuptools 0.6c7.

3.0a2

  - Fixed the README.txt example for defining the supervisor RPC
    interface in the configuration file.  Thanks to Drew Perttula.

  - Fixed a bug where process communication events would not have the
    proper payload if the payload data was very short.

  - when supervisord attempted to kill a process with SIGKILL after
    the process was not killed within "stopwaitsecs" using a "normal"
    kill signal, supervisord would crash with an improper
    AssertionError.  Thanks to Calvin Hendryx-Parker.

  - On Linux, Supervisor would consume too much CPU in an effective
    "busywait" between the time a subprocess exited and the time at
    which supervisor was notified of its exit status.  Thanks to Drew
    Perttula.

  - RPC interface behavior change: if the RPC method
    "sendProcessStdin" is called against a process that has closed its
    stdin file descriptor (e.g. it has done the equivalent of
    "sys.stdin.close(); os.close(0)"), we return a NO_FILE fault
    instead of accepting the data.

  - Changed the semantics of the process configuration 'autorestart'
    parameter with respect to processes which move between the RUNNING
    and EXITED state.  'autorestart' was previously a boolean.  Now
    it's a trinary, accepting one of 'false', 'unexpected', or 'true'.
    If it's 'false', a process will never be automatically restarted
    from the EXITED state.  If it's 'unexpected', a process that
    enters the EXITED state will be automatically restarted if it
    exited with an exit code that was not named in the process
    config's 'exitcodes' list.  If it's 'true', a process that enters
    the EXITED state will be automatically restarted unconditionally.
    The default is now 'unexpected' (it was previously 'true').  The
    readdition of this feature is a reversion of the behavior change
    note in the changelog notes for 3.0a1 that asserted we never cared
    about the process' exit status when determining whether to restart
    it or not.

  - setup.py develop (and presumably setup.py install) would fail
    under Python 2.3.3, because setuptools attempted to import
    'splituser' from urllib2, and it didn't exist.

  - It's now possible to use 'setup.py install' and 'setup.py develop'
    on systems which do not have a C compiler if you set the
    environment variable "NO_MELD3_EXTENSION_MODULES=1" in the shell
    in which you invoke these commands (versions of meld3 > 0.6.1
    respect this envvar and do not try to compile optional C
    extensions when it's set).

  - The test suite would fail on Python versions <= 2.3.3 because
    the "assertTrue" and "assertFalse" methods of unittest.TestCase
    didn't exist in those versions.

  - The 'supervisorctl' and 'supervisord' wrapper scripts were disused
    in favor of using setuptools' 'console_scripts' entry point settings.

  - Documentation files and the sample configuration file are put into
    the generated supervisor egg's 'doc' directory.

  _ Using the web interface would cause fairly dramatic memory
    leakage.  We now require a version of meld3 that does not appear
    to leak memory from its C extensions (0.6.3).

3.0a1

  - Default config file comment documented 10 secs as default for
    'startsecs' value in process config, in reality it was 1 sec.
    Thanks to Christoph Zwerschke.

  - Make note of subprocess environment behavior in README.txt.
    Thanks to Christoph Zwerschke.

  - New "strip_ansi" config file option attempts to strip ANSI escape
    sequences from logs for smaller/more readable logs (submitted by
    Mike Naberezny).

  - The XML-RPC method supervisor.getVersion() has been renamed for 
    clarity to supervisor.getAPIVersion().  The old name is aliased 
    for compatibility but is deprecated and will be removed in a
    future version (Mike Naberezny).

  - Improved web interface styling (Mike Naberezny, Derek DeVries)

  - The XML-RPC method supervisor.startProcess() now checks that
    the file exists and is executable (Mike Naberezny).

  - Two environment variables, "SUPERVISOR_PROCESS_NAME" and
    "SUPERVISOR_PROCESS_GROUP" are set in the environment of child
    processes, representing the name of the process and group in
    supervisor's configuration.

  - Process state map change: a process may now move directly from the
    STARTING state to the STOPPING state (as a result of a stop
    request).

  - Behavior change: if 'autorestart' is true, even if a process exits
    with an "expected" exit code, it will still be restarted.  In the
    immediately prior release of supervisor, this was true anyway, and
    no one complained, so we're going to consider that the "officially
    correct" behavior from now on.

  - Supervisor now logs subprocess stdout and stderr independently.
    The old program config keys "logfile", "logfile_backups" and
    "logfile_maxbytes" are superseded by "stdout_logfile",
    "stdout_logfile_backups", and "stdout_logfile_maxbytes".  Added
    keys include "stderr_logfile", "stderr_logfile_backups", and
    "stderr_logfile_maxbytes".  An additional "redirect_stderr" key is
    used to cause program stderr output to be sent to its stdin
    channel.  The keys "log_stderr" and "log_stdout" have been
    removed.

  - '[program:x]' config file sections now represent "homgeneous
    process groups" instead of single processes.  A "numprocs" key in
    the section represents the number of processes that are in the
    group.  A "process_name" key in the section allows composition of
    the each process' name within the homogeneous group.

  - A new kind of config file section, '[group:x]' now exists,
    allowing users to group heterogeneous processes together into a
    process group that can be controlled as a unit from a client.

  - Supervisord now emits "events" at certain points in its normal
    operation.  These events include supervisor state change events,
    process state change events, and "process communication events".

  - A new kind of config file section '[eventlistener:x]' now exists.
    Each section represents an "event listener pool", which is a
    special kind of homogeneous process group.  Each process in the
    pool is meant to receive supervisor "events" via its stdin and
    perform some notification (e.g. send a mail, log, make an http
    request, etc.)

  - Supervisord can now capture data between special tokens in
    subprocess stdout/stderr output and emit a "process communications
    event" as a result.

  - Supervisor's XML-RPC interface may be extended arbitrarily by
    programmers.  Additional top-level namespace XML-RPC interfaces
    can be added using the '[rpcinterface:foo]' declaration in the
    configuration file.

  - New 'supervisor'-namespace XML-RPC methods have been added:
    getAPIVersion (returns the XML-RPC API version, the older
    "getVersion" is now deprecated), "startProcessGroup" (starts all
    processes in a supervisor process group), "stopProcessGroup"
    (stops all processes in a supervisor process group), and
    "sendProcessStdin" (sends data to a process' stdin file
    descriptor).

  - 'supervisor'-namespace XML-RPC methods which previously accepted
    ony a process name as "name" (startProcess, stopProcess,
    getProcessInfo, readProcessLog, tailProcessLog, and
    clearProcessLog) now accept a "name" which may contain both the
    process name and the process group name in the form
    'groupname:procname'.  For backwards compatibility purposes,
    "simple" names will also be accepted but will be expanded
    internally (e.g. if "foo" is sent as a name, it will be expanded
    to "foo:foo", representing the foo process within the foo process
    group).

  - 2.X versions of supervisorctl will work against supervisor 3.0
    servers in a degraded fashion, but 3.X versions of supervisorctl
    will not work at all against supervisor 2.X servers.

  Known issues:

    - supervisorctl and the web interface do not yet allow you to stop
      / start / restart a process group as a unit.

    - supervisorctl and the web interface do not allow you to tail or
      otherwise examine stderr log files of processes.

    - buffered event notifications may be lost at supervisor shutdown
      or restart time.

  Acknowledgements:

    Maintainable Software (http://www.maintainable.com) contracted
    Agendless Consulting to add the event notification features and
    extensible XML-RPC namespaces feature to supervisor.

2.2b1

  - Individual program configuration sections can now specify an
    environment.

  - Added a 'version' command to supervisorctl.  This returns the
    version of the supervisor2 package which the remote supervisord
    process is using.

2.1

  - When supervisord was invoked more than once, and its configuration
    was set up to use a UNIX domain socket as the HTTP server, the
    socket file would be erased in error.  The symptom of this was
    that a subsequent invocation of supervisorctl could not find the
    socket file, so the process could not be controlled (it and all of
    its subprocesses would need to be killed by hand).

  - Close subprocess file descriptors properly when a subprocess exits
    or otherwise dies.  This should result in fewer "too many open
    files to spawn foo" messages when supervisor is left up for long
    periods of time.

  - When a process was not killable with a "normal" signal at shutdown
    time, too many "INFO: waiting for x to die" messages would be sent
    to the log until we ended up killing the process with a SIGKILL.
    Now a maximum of one every three seconds is sent up until SIGKILL
    time.  Thanks to Ian Bicking.

  - Add an assertion: we never want to try to marshal None to XML-RPC
    callers.  Issue 223 in the collector from vgatto indicates that
    somehow a supervisor XML-RPC method is returning None (which
    should never happen), but I cannot identify how.  Maybe the
    assertion will give us more clues if it happens again.

  - Supervisor would crash when run under Python 2.5 because the
    xmlrpclib.Transport class in Python 2.5 changed in a
    backward-incompatible way.  Thanks to Eric Westra for the bug
    report and a fix.

  - Tests now pass under Python 2.5.

  - Better supervisorctl reporting on stop requests that have a FAILED
    status.

  - Removed duplicated code (readLog/readMainLog), thanks to Mike
    Naberezny.

  - Added tailProcessLog command to the XML-RPC API.  It provides a
    more efficient way to tail logs than readProcessLog().  Use
    readProcessLog() to read chunks and tailProcessLog() to tail.
    (thanks to Mike Naberezny).

2.1b2

  - Added new tailProcessLog() command to the XML-RPC API that
    is more efficient for just tailing than the existing
    readProcessLog() command (Mike Naberezny).

2.1b1

  - "supervisord -h" and "supervisorctl -h" did not work (traceback
    instead of showing help view (thanks to Damjan from Macedonia for
    the bug report).

  - Processes which started successfully after failing to start
    initially are no longer reported in BACKOFF state once they are
    started successfully (thanks to Damjan from Macdonia for the bug
    report).

  - Add new 'maintail' command to supervisorctl shell, which allows
    you to tail the 'main' supervisor log.  This uses a new
    readMainLog xmlrpc API.

  - Various process-state-transition related changes, all internal.
    README.txt updated with new state transition map.

  - startProcess and startAllProcesses xmlrpc APIs changed: instead of
    accepting a timeout integer, these accept a wait boolean (timeout
    is implied by process' "startsecs" configuration).  If wait is
    False, do not wait for startsecs.

  Known issues:

    Code does not match state transition map.  Processes which are
    configured as autorestarting which start "successfully" but
    subsequently die after 'startsecs' go through the transitions
    RUNNING -> BACKOFF -> STARTING instead of the correct transitions
    RUNNING -> EXITED -> STARTING.  This has no real negative effect,
    but should be fixed for correctness.

2.0

  - pidfile written in daemon mode had incorrect pid.

  - supervisorctl: tail (non -f) did not pass through proper error
    messages when supplied by the server.

  - Log signal name used to kill processes at debug level.

  - supervisorctl "tail -f" didn't work with supervisorctl sections
    configured with an absolute unix:// URL

  - New "environment" config file option allows you to add environment
    variable values to supervisord environment from config file.

2.0b1

  - fundamental rewrite based on 1.0.6, use distutils (only) for
    installation, use ConfigParser rather than ZConfig, use HTTP for
    wire protocol, web interface, less lies in supervisorctl.