Fix wsgi documentation

This way, errors like "database already locked" can be fixed and the
page reloaded, without needing to restart Apache.

README.txt

@@ -24,3 +24,5 @@ Usage:
 
   nilmdb-server --help
   nilmtool --help
+
+See docs/wsgi.md for info on setting up a WSGI application in Apache.

docs/wsgi.md

@@ -0,0 +1,31 @@
+WSGI Application in Apache
+--------------------------
+
+Install `apache2` and `libapache2-mod-wsgi`
+
+We'll set up the database server at URL `http://myhost.com/nilmdb`.
+The database will be stored in `/home/nilm/db`, and the process will
+run as user `nilm`, group `nilm`.
+
+First, create a WSGI script `/home/nilm/nilmdb.wsgi` containing:
+
+    import nilmdb.server
+    application = nilmdb.server.wsgi_application("/home/nilm/db", "/nilmdb")
+
+The first parameter is the local filesystem path, and the second
+parameter is the path part of the URL.
+
+Then, set up Apache with a configuration like:
+
+    <VirtualHost>
+        WSGIScriptAlias /nilmdb /home/nilm/nilmdb.wsgi
+        WSGIProcessGroup nilmdb-server
+        WSGIDaemonProcess nilmdb-server threads=32 user=nilm group=nilm
+
+        # Access control example:
+        <Location /nilmdb>
+            Order deny,allow
+            Deny from all
+            Allow from 1.2.3.4
+        </Location>
+    </VirtualHost>

nilmdb/client/httpclient.py

@@ -16,7 +16,7 @@ class HTTPClient(object):
         reparsed = urlparse.urlparse(baseurl).geturl()
         if '://' not in reparsed:
             reparsed = urlparse.urlparse("http://" + baseurl).geturl()
-        self.baseurl = reparsed
+        self.baseurl = reparsed.rstrip('/') + '/'
 
         # Build Requests session object, enable SSL verification
         self.session = requests.Session()

nilmdb/scripts/nilmdb_server.py

@@ -22,7 +22,7 @@ def main():
     group.add_argument('-p', '--port', help = 'Listen on the given port',
                        type = int, default = 12380)
     group.add_argument('-d', '--database', help = 'Database directory',
-                       default = os.path.join(os.getcwd(), "db"))
+                       default = "./db")
     group.add_argument('-q', '--quiet', help = 'Silence output',
                        action = 'store_true')
     group.add_argument('-t', '--traceback',

nilmdb/server/__init__.py

@@ -17,5 +17,5 @@ except (ImportError, TypeError): # pragma: no cover
     pass
 
 from nilmdb.server.nilmdb import NilmDB
-from nilmdb.server.server import Server
+from nilmdb.server.server import Server, wsgi_application
 from nilmdb.server.errors import NilmDBError, StreamError, OverlapError

nilmdb/server/bulkdata.py

@@ -14,6 +14,7 @@ import re
 import sys
 import tempfile
 
+import nilmdb.utils.lock
 from . import rocket
 
 # Up to 256 open file descriptors at any given time.
@@ -26,6 +27,8 @@ class BulkData(object):
     def __init__(self, basepath, **kwargs):
         self.basepath = basepath
         self.root = os.path.join(self.basepath, "data")
+        self.lock = self.root + ".lock"
+        self.lockfile = None
 
         # Tuneables
         if "file_size" in kwargs:
@@ -44,8 +47,22 @@ class BulkData(object):
         if not os.path.isdir(self.root):
             os.mkdir(self.root)
 
+        # Create the lock
+        self.lockfile = open(self.lock, "w")
+        if not nilmdb.utils.lock.exclusive_lock(self.lockfile):
+            raise IOError('database at "' + self.basepath +
+                          '" is already locked by another process')
+
     def close(self):
         self.getnode.cache_remove_all()
+        if self.lockfile:
+            nilmdb.utils.lock.exclusive_unlock(self.lockfile)
+            self.lockfile.close()
+            try:
+                os.unlink(self.lock)
+            except OSError: # pragma: no cover
+                pass
+            self.lockfile = None
 
     def _encode_filename(self, path):
         # Encode all paths to UTF-8, regardless of sys.getfilesystemencoding(),
@@ -134,7 +151,7 @@ class BulkData(object):
 
             # Open and cache it
             self.getnode(unicodepath)
-        except:
+        except Exception:
             exc_info = sys.exc_info()
             try:
                 os.rmdir(ospath)
@@ -371,7 +388,7 @@ class Table(object):
             # Try deleting subdir, too
             try:
                 os.rmdir(os.path.join(self.root, subdir))
-            except:
+            except Exception:
                 pass
 
     # Cache open files
@@ -504,7 +521,7 @@ class Table(object):
             with open(cachefile, "rb") as f:
                 ranges = pickle.load(f)
             cachefile_present = True
-        except:
+        except Exception:
             ranges = []
             cachefile_present = False
 

nilmdb/server/nilmdb.py

@@ -106,7 +106,9 @@ class NilmDB(object):
         try:
             os.makedirs(self.basepath)
         except OSError as e:
-            if e.errno != errno.EEXIST:
+            if e.errno != errno.EEXIST: # pragma: no cover
+                # (no coverage, because it's hard to trigger this case
+                # if tests are run as root)
                 raise IOError("can't create tree " + self.basepath)
 
         # Our data goes inside it
@@ -117,8 +119,9 @@ class NilmDB(object):
         self.con = sqlite3.connect(sqlfilename, check_same_thread = True)
         try:
             self._sql_schema_update()
-        finally: # pragma: no cover
+        except Exception: # pragma: no cover
             self.data.close()
+            raise
 
         # See big comment at top about the performance implications of this
         self.con.execute("PRAGMA synchronous=NORMAL")

nilmdb/server/server.py

@@ -14,6 +14,7 @@ import os
 import simplejson as json
 import decorator
 import psutil
+import traceback
 
 class NilmApp(object):
     def __init__(self, db):
@@ -466,7 +467,8 @@ class Server(object):
                  stoppable = False,       # whether /exit URL exists
                  embedded = True,         # hide diagnostics and output, etc
                  fast_shutdown = False,   # don't wait for clients to disconn.
-                 force_traceback = False  # include traceback in all errors
+                 force_traceback = False, # include traceback in all errors
+                 basepath = '',           # base URL path for cherrypy.tree
                  ):
         # Save server version, just for verification during tests
         self.version = nilmdb.__version__
@@ -526,7 +528,7 @@ class Server(object):
         if stoppable:
             root.exit = Exiter()
         cherrypy.tree.apps = {}
-        cherrypy.tree.mount(root, "/", config = { "/" : app_config })
+        cherrypy.tree.mount(root, basepath, config = { "/" : app_config })
 
         # Shutdowns normally wait for clients to disconnect.  To speed
         # up tests, set fast_shutdown = True
@@ -536,6 +538,9 @@ class Server(object):
         else:
             cherrypy.server.shutdown_timeout = 5
 
+        # Set up the WSGI application pointer for external programs
+        self.wsgi_application = cherrypy.tree
+
     def json_error_page(self, status, message, traceback, version):
         """Return a custom error page in JSON so the client can parse it"""
         errordata = { "status" : status,
@@ -602,3 +607,46 @@ class Server(object):
 
     def stop(self):
         cherrypy.engine.exit()
+
+def wsgi_application(dbpath, basepath): # pragma: no cover
+    """Return a WSGI application object with a database at the
+    specified path.
+
+    'dbpath' is a filesystem location, e.g. /home/nilm/db
+
+    'basepath' is the URL path of the application base, which
+    is the same as the first argument to Apache's WSGIScriptAlias
+    directive.
+    """
+    server = [None]
+    def application(environ, start_response):
+        if server[0] is None:
+            # Try to start the server
+            try:
+                db = nilmdb.utils.serializer_proxy(nilmdb.server.NilmDB)(dbpath)
+                server[0] = nilmdb.server.Server(
+                    db, embedded = True,
+                    basepath = basepath.rstrip('/'))
+            except Exception:
+                # Build an error message on failure
+                err = sprintf("Initializing database at path '%s' failed:\n\n",
+                              dbpath)
+                err += traceback.format_exc()
+                try:
+                    import pwd
+                    import grp
+                    err += sprintf("\nRunning as: uid=%d (%s), gid=%d (%s)\n",
+                                   os.getuid(), pwd.getpwuid(os.getuid())[0],
+                                   os.getgid(), grp.getgrgid(os.getgid())[0])
+                except ImportError:
+                    pass
+        if server[0] is None:
+            # Serve up the error with our own mini WSGI app.
+            headers = [ ('Content-type', 'text/plain'),
+                        ('Content-length', str(len(err))) ]
+            start_response("500 Internal Server Error", headers)
+            return [err]
+
+        # Call the normal application
+        return server[0].wsgi_application(environ, start_response)
+    return application

nilmdb/utils/__init__.py

@@ -1,7 +1,7 @@
 """NilmDB utilities"""
 
+from __future__ import absolute_import
 from nilmdb.utils.timer import Timer
-from nilmdb.utils.iteratorizer import Iteratorizer
 from nilmdb.utils.serializer import serializer_proxy
 from nilmdb.utils.lrucache import lru_cache
 from nilmdb.utils.diskusage import du, human_size
@@ -12,3 +12,4 @@ import nilmdb.utils.fallocate
 import nilmdb.utils.time
 import nilmdb.utils.iterator
 import nilmdb.utils.interval
+import nilmdb.utils.lock

nilmdb/utils/iteratorizer.py

@@ -1,100 +0,0 @@
-import Queue
-import threading
-import sys
-import contextlib
-
-# This file provides a context manager that converts a function
-# that takes a callback into a generator that returns an iterable.
-# This is done by running the function in a new thread.
-
-# Based partially on http://stackoverflow.com/questions/9968592/
-
-class IteratorizerThread(threading.Thread):
-    def __init__(self, queue, function, curl_hack):
-        """
-        function: function to execute, which takes the
-        callback (provided by this class) as an argument
-        """
-        threading.Thread.__init__(self)
-        self.name = "Iteratorizer-" + function.__name__ + "-" + self.name
-        self.function = function
-        self.queue = queue
-        self.die = False
-        self.curl_hack = curl_hack
-
-    def callback(self, data):
-        try:
-            if self.die:
-                raise Exception() # trigger termination
-            self.queue.put((1, data))
-        except:
-            if self.curl_hack:
-                # We can't raise exceptions, because the pycurl
-                # extension module will unconditionally print the
-                # exception itself, and not pass it up to the caller.
-                # Instead, just return a value that tells curl to
-                # abort.  (-1 would be best, in case we were given 0
-                # bytes, but the extension doesn't support that).
-                self.queue.put((2, sys.exc_info()))
-                return 0
-            raise
-
-    def run(self):
-        try:
-            result = self.function(self.callback)
-        except:
-            self.queue.put((2, sys.exc_info()))
-        else:
-            self.queue.put((0, result))
-
-@contextlib.contextmanager
-def Iteratorizer(function, curl_hack = False):
-    """
-    Context manager that takes a function expecting a callback,
-    and provides an iterable that yields the values passed to that
-    callback instead.
-
-    function: function to execute, which takes a callback
-    (provided by this context manager) as an argument
-
-        with iteratorizer(func) as it:
-            for i in it:
-                print 'callback was passed:', i
-        print 'function returned:', it.retval
-    """
-    queue = Queue.Queue(maxsize = 1)
-    thread = IteratorizerThread(queue, function, curl_hack)
-    thread.daemon = True
-    thread.start()
-
-    class iteratorizer_gen(object):
-        def __init__(self, queue):
-            self.queue = queue
-            self.retval = None
-
-        def __iter__(self):
-            return self
-
-        def next(self):
-            (typ, data) = self.queue.get()
-            if typ == 0:
-                # function has returned
-                self.retval = data
-                raise StopIteration
-            elif typ == 1:
-                # data is available
-                return data
-            else:
-                # callback raised an exception
-                raise data[0], data[1], data[2]
-
-    try:
-        yield iteratorizer_gen(queue)
-    finally:
-        # Ask the thread to die, if it's still running.
-        thread.die = True
-        while thread.isAlive():
-            try:
-                queue.get(True, 0.01)
-            except: # pragma: no cover
-                pass

nilmdb/utils/lock.py

@@ -0,0 +1,33 @@
+# File locking
+
+import warnings
+
+try:
+    import fcntl
+    import errno
+
+    def exclusive_lock(f):
+        """Acquire an exclusive lock.  Returns True on successful
+        lock, or False on error."""
+        try:
+            fcntl.flock(f.fileno(), fcntl.LOCK_EX | fcntl.LOCK_NB)
+        except IOError as e:
+            if e.errno in (errno.EACCES, errno.EAGAIN):
+                return False
+            else: # pragma: no cover
+                raise
+        return True
+
+    def exclusive_unlock(f):
+        """Release an exclusive lock."""
+        fcntl.flock(f.fileno(), fcntl.LOCK_UN)
+
+except ImportError: # pragma: no cover
+    def exclusive_lock(f):
+        """Dummy lock function -- does not lock!"""
+        warnings.warn("Pretending to lock " + str(f))
+        return True
+
+    def exclusive_unlock(f):
+        """Release an exclusive lock."""
+        return

nilmdb/utils/mustclose.py

@@ -15,7 +15,7 @@ def must_close(errorfile = sys.stderr, wrap_verify = False):
         def wrap_class_method(wrapper):
             try:
                 orig = getattr(cls, wrapper.__name__).im_func
-            except:
+            except Exception:
                 orig = lambda x: None
             setattr(cls, wrapper.__name__, decorator.decorator(wrapper, orig))
 

setup.py

@@ -39,7 +39,7 @@ versioneer.parentdir_prefix = 'nilmdb-'
 # Hack to workaround logging/multiprocessing issue:
 # https://groups.google.com/d/msg/nose-users/fnJ-kAUbYHQ/_UsLN786ygcJ
 try: import multiprocessing
-except: pass
+except Exception: pass
 
 # Use Cython if it's new enough, otherwise use preexisting C files.
 cython_modules = [ 'nilmdb.server.interval',

tests/runtests.py

@@ -24,7 +24,7 @@ class JimOrderPlugin(nose.plugins.Plugin):
                     name, workingDir=loader.workingDir)
                 try:
                     order = os.path.join(addr.filename, "test.order")
-                except:
+                except Exception:
                     order = None
                 if order and os.path.exists(order):
                     files = []

tests/test.order

@@ -4,7 +4,6 @@ test_lrucache.py
 test_mustclose.py
 
 test_serializer.py
-test_iteratorizer.py
 
 test_timestamper.py
 test_rbtree.py

tests/test_bulkdata.py

@@ -30,6 +30,11 @@ class TestBulkData(object):
         else:
             data = BulkData(db, file_size = size, files_per_dir = files)
 
+        # Try opening it again (should result in locking error)
+        with assert_raises(IOError) as e:
+            data2 = BulkData(db)
+        in_("already locked by another process", str(e.exception))
+
         # create empty
         with assert_raises(ValueError):
             data.create("/foo", "uint16_8")

tests/test_client.py

@@ -619,7 +619,7 @@ class TestClient(object):
                     poolmanager = c.http._last_response.connection.poolmanager
                     pool = poolmanager.pools[('http','localhost',32180)]
                     return (pool.num_connections, pool.num_requests)
-                except:
+                except Exception:
                     raise SkipTest("can't get connection info")
 
             # First request makes a connection

tests/test_interval.py

@@ -385,7 +385,6 @@ class TestIntervalSpeed:
     def test_interval_speed(self):
         import yappi
         import time
-        import testutil.aplotter as aplotter
         import random
         import math
 
@@ -406,6 +405,5 @@ class TestIntervalSpeed:
                    speed/j,
                    speed / (j*math.log(j))) # should be constant
             speeds[j] = speed
-        aplotter.plot(speeds.keys(), speeds.values(), plot_slope=True)
         yappi.stop()
         yappi.print_stats(sort_type=yappi.SORTTYPE_TTOT, limit=10)

tests/test_iteratorizer.py

@@ -1,61 +0,0 @@
-import nilmdb
-from nilmdb.utils.printf import *
-
-import nose
-from nose.tools import *
-from nose.tools import assert_raises
-import threading
-import time
-
-from testutil.helpers import *
-
-def func_with_callback(a, b, callback):
-    callback(a)
-    callback(b)
-    callback(a+b)
-    return "return value"
-
-class TestIteratorizer(object):
-    def test(self):
-
-        # First try it with a normal callback
-        self.result = ""
-        def cb(x):
-            self.result += str(x)
-        func_with_callback(1, 2, cb)
-        eq_(self.result, "123")
-
-        # Now make it an iterator
-        result = ""
-        f = lambda x: func_with_callback(1, 2, x)
-        with nilmdb.utils.Iteratorizer(f) as it:
-            for i in it:
-                result += str(i)
-        eq_(result, "123")
-        eq_(it.retval, "return value")
-
-        # Make sure things work when an exception occurs
-        result = ""
-        with nilmdb.utils.Iteratorizer(
-            lambda x: func_with_callback(1, "a", x)) as it:
-            with assert_raises(TypeError) as e:
-                for i in it:
-                    result += str(i)
-        eq_(result, "1a")
-
-        # Now try to trigger the case where we stop iterating
-        # mid-generator, and expect the iteratorizer to clean up after
-        # itself.  This doesn't have a particular result in the test,
-        # but gains coverage.
-        def foo():
-            with nilmdb.utils.Iteratorizer(f) as it:
-                it.next()
-        foo()
-        eq_(it.retval, None)
-
-        # Do the same thing when the curl hack is applied
-        def foo():
-            with nilmdb.utils.Iteratorizer(f, curl_hack = True) as it:
-                it.next()
-        foo()
-        eq_(it.retval, None)

tests/test_nilmdb.py

@@ -28,9 +28,6 @@ class Test00Nilmdb(object):  # named 00 so it runs first
     def test_NilmDB(self):
         recursive_unlink(testdb)
 
-        with assert_raises(IOError):
-            nilmdb.server.NilmDB("/nonexistant-db/foo")
-
         db = nilmdb.server.NilmDB(testdb)
         db.close()
         db = nilmdb.server.NilmDB(testdb)

tests/test_printf.py

@@ -18,7 +18,7 @@ class TestPrintf(object):
             printf("hello, world: %d", 123)
             fprintf(test2, "hello too: %d", 123)
             test3 = sprintf("hello three: %d", 123)
-        except:
+        except Exception:
             sys.stdout = old_stdout
             raise
         sys.stdout = old_stdout

tests/testutil/aplotter.py

@@ -1,419 +0,0 @@
-
-#-----------------------------------------------
-#aplotter.py - ascii art function plotter
-#Copyright (c) 2006, Imri Goldberg
-#All rights reserved.
-#
-#Redistribution and use in source and binary forms,
-#with or without modification, are permitted provided
-#that the following conditions are met:
-#
-#    * Redistributions of source code must retain the
-#		above copyright notice, this list of conditions
-#		and the following disclaimer.
-#    * Redistributions in binary form must reproduce the
-#		above copyright notice, this list of conditions
-#		and the following disclaimer in the documentation
-#		and/or other materials provided with the distribution.
-#    * Neither the name of the <ORGANIZATION> nor the names of
-#		its contributors may be used to endorse or promote products
-#		derived from this software without specific prior written permission.
-#
-#THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-#AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-#IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-#ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
-#LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
-#DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
-#SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
-#CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
-#OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-#OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-#-----------------------------------------------
-
-import math
-
-
-EPSILON = 0.000001
-
-def transposed(mat):
-	result = []
-	for i in xrange(len(mat[0])):
-		result.append([x[i] for x in mat])
-	return result
-
-def y_reversed(mat):    
-	result = []
-	for i in range(len(mat)):
-		result.append(list(reversed(mat[i])))
-	return result
-
-def sign(x):
-	if 0<x:
-		return 1
-	if 0 == x:
-		return 0
-	return -1
-
-class Plotter(object):
-
-	class PlotData(object):
-		def __init__(self, x_size, y_size, min_x, max_x, min_y, max_y, x_mod, y_mod):
-			self.x_size = x_size
-			self.y_size = y_size
-			self.min_x = min_x
-			self.max_x = max_x
-			self.min_y = min_y
-			self.max_y = max_y
-			self.x_mod = x_mod
-			self.y_mod = y_mod
-
-			self.x_step = float(max_x - min_x)/float(self.x_size)
-			self.y_step = float(max_y - min_y)/float(self.y_size)
-			self.inv_x_step = 1/self.x_step
-			self.inv_y_step = 1/self.y_step
-
-			self.ratio = self.y_step / self.x_step
-		def __repr__(self):
-			s = "size: %s, bl: %s, tr: %s, step: %s" % ((self.x_size, self.y_size), (self.min_x, self.min_y), (self.max_x, self.max_y),
-														 (self.x_step, self.y_step))
-			return s
-	
-	def __init__(self, **kwargs):
-
-		self.x_size = kwargs.get("x_size", 80)
-		self.y_size = kwargs.get("y_size", 20)
-
-		self.will_draw_axes = kwargs.get("draw_axes", True)
-
-		self.new_line = kwargs.get("newline", "\n")
-
-		self.dot = kwargs.get("dot", "*")
-
-		self.plot_slope = kwargs.get("plot_slope", True)
-
-		self.x_margin = kwargs.get("x_margin", 0.05)
-		self.y_margin = kwargs.get("y_margin", 0.1)
-
-		self.will_plot_labels = kwargs.get("plot_labels", True)
-
-	@staticmethod
-	def get_symbol_by_slope(slope, default_symbol):
-		draw_symbol = default_symbol
-		if slope > math.tan(3*math.pi/8):
-			draw_symbol = "|"
-		elif slope > math.tan(math.pi/8) and slope < math.tan(3*math.pi/8):
-			draw_symbol = "/"
-		elif abs(slope) < math.tan(math.pi/8):
-			draw_symbol = "-"
-		elif slope < math.tan(-math.pi/8) and slope > math.tan(-3*math.pi/8):
-			draw_symbol = "\\"
-		elif slope < math.tan(-3*math.pi/8):
-			draw_symbol = "|"
-		return draw_symbol    
-
-
-	def plot_labels(self, output_buffer, plot_data):
-		if plot_data.y_size < 2:
-			return
-
-		margin_factor = 1
-
-		do_plot_x_label = True
-		do_plot_y_label = True
-
-		x_str = "%+g"
-		if plot_data.x_size < 16:
-			do_plot_x_label = False
-		elif plot_data.x_size < 23:
-			x_str = "%+.2g" 
-
-		y_str = "%+g"    
-		if plot_data.x_size < 8:
-			do_plot_y_label = False
-		elif plot_data.x_size < 11:
-			y_str = "%+.2g"
-			
-		act_min_x = (plot_data.min_x + plot_data.x_mod*margin_factor)
-		act_max_x = (plot_data.max_x - plot_data.x_mod*margin_factor)
-		act_min_y = (plot_data.min_y + plot_data.y_mod*margin_factor)
-		act_max_y = (plot_data.max_y - plot_data.y_mod*margin_factor)
-
-		if abs(act_min_x) < 1:
-			min_x_str = "%+.2g" % act_min_x
-		else:
-			min_x_str = x_str % act_min_x
-
-		if abs(act_max_x) < 1:
-			max_x_str = "%+.2g" % act_max_x
-		else:
-			max_x_str = x_str % act_max_x
-		
-		if abs(act_min_y) < 1:
-			min_y_str = "%+.2g" % act_min_y
-		else:
-			min_y_str = y_str % act_min_y
-
-		if abs(act_max_y) < 1:
-			max_y_str = "%+.2g" % act_max_y
-		else:
-			max_y_str = y_str % act_max_y
-						 
-		min_x_coord = self.get_coord(act_min_x,plot_data.min_x,plot_data.x_step)
-		max_x_coord = self.get_coord(act_max_x,plot_data.min_x,plot_data.x_step)
-		min_y_coord = self.get_coord(act_min_y,plot_data.min_y,plot_data.y_step)
-		max_y_coord = self.get_coord(act_max_y,plot_data.min_y,plot_data.y_step)
-								 
-
-		#print plot_data
-		
-		y_zero_coord = self.get_coord(0, plot_data.min_y, plot_data.y_step)
-
-		#if plot_data.min_x < 0 and plot_data.max_x > 0:
-		x_zero_coord = self.get_coord(0, plot_data.min_x, plot_data.x_step)
-		#else:
-		
-		#pass
-
-		output_buffer[x_zero_coord][min_y_coord] = "+"
-		output_buffer[x_zero_coord][max_y_coord] = "+"
-		output_buffer[min_x_coord][y_zero_coord] = "+"
-		output_buffer[max_x_coord][y_zero_coord] = "+"
-
-		if do_plot_x_label:        
-
-			for i,c in enumerate(min_x_str):
-				output_buffer[min_x_coord+i][y_zero_coord-1] = c
-			for i,c in enumerate(max_x_str):
-				output_buffer[max_x_coord+i-len(max_x_str)][y_zero_coord-1] = c
-
-		if do_plot_y_label:
-
-			for i,c in enumerate(max_y_str):
-				output_buffer[x_zero_coord+i][max_y_coord] = c
-			for i,c in enumerate(min_y_str):
-				output_buffer[x_zero_coord+i][min_y_coord] = c
-			
-
-		
-		
-	
-	def plot_data(self, xy_seq, output_buffer, plot_data):
-		if self.plot_slope:
-			xy_seq = list(xy_seq)
-			#sort according to the x coord
-			xy_seq.sort(key = lambda c: c[0])
-			prev_p = xy_seq[0]
-			e_xy_seq = enumerate(xy_seq)
-			e_xy_seq.next()
-			for i,(x,y) in e_xy_seq:
-				draw_symbol = self.dot
-				line_drawn = self.plot_line(prev_p, (x,y), output_buffer, plot_data)
-				prev_p = (x,y)
-				if not line_drawn:
-					if i > 0 and i < len(xy_seq)-1:
-						px,py = xy_seq[i-1]
-						nx,ny = xy_seq[i+1]
-
-						if abs(nx-px) > EPSILON:
-							slope = (1.0/plot_data.ratio)*(ny-py)/(nx-px)
-							draw_symbol = self.get_symbol_by_slope(slope, draw_symbol)
-					if x < plot_data.min_x or x >= plot_data.max_x or y < plot_data.min_y or y >= plot_data.max_y:
-						continue
-					
-					x_coord = self.get_coord(x, plot_data.min_x, plot_data.x_step)
-					y_coord = self.get_coord(y, plot_data.min_y, plot_data.y_step)            
-					if x_coord >= 0 and x_coord < len(output_buffer) and y_coord >= 0 and y_coord < len(output_buffer[0]):
-						if self.draw_axes:
-							if y_coord == self.get_coord(0, plot_data.min_y, plot_data.y_step) and draw_symbol == "-":
-								draw_symbol = "="
-						output_buffer[x_coord][y_coord] = draw_symbol
-		else:
-			for x,y in xy_seq:
-				if x < plot_data.min_x or x >= plot_data.max_x or y < plot_data.min_y or y >= plot_data.max_y:
-					continue
-				x_coord = self.get_coord(x, plot_data.min_x, plot_data.x_step)
-				y_coord = self.get_coord(y, plot_data.min_y, plot_data.y_step)
-				if x_coord >= 0 and x_coord < len(output_buffer) and y_coord > 0 and y_coord < len(output_buffer[0]):
-					output_buffer[x_coord][y_coord] = self.dot
-
-
-	def plot_line(self, start, end, output_buffer, plot_data):
-
-		start_coord = self.get_coord(start[0], plot_data.min_x, plot_data.x_step), self.get_coord(start[1], plot_data.min_y, plot_data.y_step)
-		end_coord = self.get_coord(end[0], plot_data.min_x, plot_data.x_step), self.get_coord(end[1], plot_data.min_y, plot_data.y_step)
-
-		x0,y0 = start_coord
-		x1,y1 = end_coord
-		if (x0,y0) == (x1,y1):
-			return True    
-		
-		clipped_line = clip_line(start, end, (plot_data.min_x, plot_data.min_y), (plot_data.max_x, plot_data.max_y))
-		if clipped_line != None:
-			start,end = clipped_line
-		else:
-			return False
-		start_coord = self.get_coord(start[0], plot_data.min_x, plot_data.x_step), self.get_coord(start[1], plot_data.min_y, plot_data.y_step)
-		end_coord = self.get_coord(end[0], plot_data.min_x, plot_data.x_step), self.get_coord(end[1], plot_data.min_y, plot_data.y_step)
-
-		x0,y0 = start_coord
-		x1,y1 = end_coord
-		if (x0,y0) == (x1,y1):
-			return True
-		x_zero_coord = self.get_coord(0, plot_data.min_x, plot_data.x_step)
-		y_zero_coord = self.get_coord(0, plot_data.min_y, plot_data.y_step)   
-
-		if start[0]-end[0] == 0:
-			draw_symbol = "|"
-		else:
-			slope = (1.0/plot_data.ratio)*(end[1]-start[1])/(end[0]-start[0])
-			draw_symbol = self.get_symbol_by_slope(slope, self.dot)
-		try:
-
-			delta = x1-x0, y1-y0
-			if abs(delta[0])>abs(delta[1]):
-				s = sign(delta[0])
-				slope = float(delta[1])/delta[0]
-				for i in range(0,abs(int(delta[0]))):
-					cur_draw_symbol = draw_symbol
-					x = i*s
-					cur_y = int(y0+slope*x)
-					if self.draw_axes and cur_y == y_zero_coord and draw_symbol == "-":
-						cur_draw_symbol = "="
-					output_buffer[x0+x][cur_y] = cur_draw_symbol
-				
-				
-			else:
-				s = sign(delta[1])
-				slope = float(delta[0])/delta[1]
-				for i in range(0,abs(int(delta[1]))):
-					y = i*s
-					cur_draw_symbol = draw_symbol
-					cur_y = y0+y
-					if self.draw_axes and cur_y == y_zero_coord and draw_symbol == "-":
-						cur_draw_symbol = "="
-					output_buffer[int(x0+slope*y)][cur_y] = cur_draw_symbol
-		except:
-			print start, end
-			print start_coord, end_coord
-			print plot_data
-			raise
-
-		return False            
-		
-		
-	def plot_single(self, seq, min_x = None, max_x = None, min_y = None, max_y = None):
-		return self.plot_double(range(len(seq)),seq, min_x, max_x, min_y, max_y)
-		
-
-
-
-	def plot_double(self, x_seq, y_seq, min_x = None, max_x = None, min_y = None, max_y = None):
-		if min_x == None:
-			min_x = min(x_seq)
-		if max_x == None:
-			max_x = max(x_seq)
-		if min_y == None:
-			min_y = min(y_seq)
-		if max_y == None:
-			max_y = max(y_seq)
-
-		if max_y == min_y:
-			max_y += 1
-
-		x_mod = (max_x-min_x)*self.x_margin
-		y_mod = (max_y-min_y)*self.y_margin
-		min_x-=x_mod
-		max_x+=x_mod
-		min_y-=y_mod
-		max_y+=y_mod
-
-
-		plot_data = self.PlotData(self.x_size, self.y_size, min_x, max_x, min_y, max_y, x_mod, y_mod)
-
-		output_buffer = [[" "]*self.y_size for i in range(self.x_size)]
-
-		if self.will_draw_axes:
-			self.draw_axes(output_buffer, plot_data)
-
-		self.plot_data(zip(x_seq, y_seq), output_buffer, plot_data)
-
-		if self.will_plot_labels:
-			self.plot_labels(output_buffer, plot_data)
-
-		trans_result = transposed(y_reversed(output_buffer))
-
-		result = self.new_line.join(["".join(row) for row in trans_result])
-		return result
-
-	def draw_axes(self, output_buffer, plot_data):
-		
-		
-		draw_x = False
-		draw_y = False
-
-		if plot_data.min_x <= 0 and plot_data.max_x > 0:
-			draw_y = True
-			zero_x = self.get_coord(0, plot_data.min_x, plot_data.x_step)
-			for y in xrange(plot_data.y_size):
-				output_buffer[zero_x][y] = "|"
-				
-		if plot_data.min_y <= 0 and plot_data.max_y > 0:
-			draw_x = True
-			zero_y = self.get_coord(0, plot_data.min_y, plot_data.y_step)    
-			for x in xrange(plot_data.x_size):
-				output_buffer[x][zero_y] = "-"
-
-		if draw_x and draw_y:
-			output_buffer[zero_x][zero_y] = "+"
-		
-		
-	@staticmethod
-	def get_coord(val, min, step):
-		result = int((val - min)/step)
-		return result
-
-def clip_line(line_pt_1, line_pt_2, rect_bottom_left, rect_top_right):
-	ts = [0.0,1.0]
-	if line_pt_1[0] == line_pt_2[0]:
-		return ((line_pt_1[0], max(min(line_pt_1[1], line_pt_2[1]), rect_bottom_left[1])),
-				(line_pt_1[0], min(max(line_pt_1[1], line_pt_2[1]), rect_top_right[1])))
-	if line_pt_1[1] == line_pt_2[1]:
-		return ((max(min(line_pt_1[0], line_pt_2[0]), rect_bottom_left[0]), line_pt_1[1]),
-				(min(max(line_pt_1[0], line_pt_2[0]), rect_top_right[0]), line_pt_1[1]))
-
-	if ((rect_bottom_left[0] <= line_pt_1[0] and line_pt_1[0] < rect_top_right[0]) and
-		(rect_bottom_left[1] <= line_pt_1[1] and line_pt_1[1] < rect_top_right[1]) and
-		(rect_bottom_left[0] <= line_pt_2[0] and line_pt_2[0] < rect_top_right[0]) and
-		(rect_bottom_left[1] <= line_pt_2[1] and line_pt_2[1] < rect_top_right[1])):
-		return line_pt_1, line_pt_2
-
-	ts.append( float(rect_bottom_left[0]-line_pt_1[0])/(line_pt_2[0]-line_pt_1[0]) )
-	ts.append( float(rect_top_right[0]-line_pt_1[0])/(line_pt_2[0]-line_pt_1[0]) )
-	ts.append( float(rect_bottom_left[1]-line_pt_1[1])/(line_pt_2[1]-line_pt_1[1]) )
-	ts.append( float(rect_top_right[1]-line_pt_1[1])/(line_pt_2[1]-line_pt_1[1]) )
-	
-	ts.sort()
-	if ts[2] < 0 or ts[2] >= 1 or ts[3] < 0 or ts[2]>= 1:
-		return None
-	result = [(pt_1 + t*(pt_2-pt_1)) for t in (ts[2],ts[3]) for (pt_1, pt_2) in zip(line_pt_1, line_pt_2)]
-	return (result[0],result[1]), (result[2], result[3])
-	
-
-
-def plot(*args,**flags):
-	limit_flags_names = set(["min_x","min_y","max_x","max_y"])
-	limit_flags = dict([(n,flags[n]) for n in limit_flags_names & set(flags)])
-	settting_flags = dict([(n,flags[n]) for n in set(flags) - limit_flags_names])
-	
-	if len(args) == 1:
-		p = Plotter(**settting_flags)
-		print p.plot_single(args[0],**limit_flags)
-	elif len(args) == 2:
-		p = Plotter(**settting_flags)
-		print p.plot_double(args[0],args[1],**limit_flags)
-	else:
-		raise NotImplementedError("can't draw multiple graphs yet")
-	
-__all__ = ["Plotter","plot"]
-