**inside the blueprint add:**

    from flask import current_app

**and when needed call:**

    current_app.logger.info(&#39;grolsh&#39;)

Btw, I use this pattern:

    # core.py
    from werkzeug.local import LocalProxy
    from flask import current_app

    logger = LocalProxy(lambda: current_app.logger)


    # views.py
    from core import logger

    @mod.route(&quot;/&quot;)
    def index():
        logger.info(&quot;serving index&quot;)
        ...


I am working on an application that demonstrates the _Djikstra&#39;s algorithm_, and to use it, I need to restore the heap property when my elements&#39; value is decreased.

The problem regarding the complexity is that **when the algorithm changes the value of an element, that element&#39;s index** in the internal structure (heap in this case) used for the priority queue **is unknown**. As such, I currently need to do an O(n) search, in order to recover the index, before I can perform an actual _decrease-key_ on it.

Moreover, I am not exactly sure about the actual code needed for the operation. I am using the D-Heap [here][1] for my Priority Queue. Pseudocode would help, but I would prefer an example in Java on how this should be done.


  [1]: http://en.algoritmy.net/article/41909/D-ary-heap

How to implement O(logn) decrease-key operation for min-heap based Priority Queue?

I&#39;m using Twitter Bootstrap&#39;s popover on the dynamic list. The list item has a button, when I click the button, it should show up popover. It works fine when I tested on non-dynamic.  

this is my JavaScript for non-dynamic list

    $(&quot;button[rel=popover]&quot;).popover({ 
        placement : &#39;right&#39;,
    	container : &#39;body&#39;,
    	html : true,
    	//content:&quot; &lt;div style=&#39;color:red&#39;&gt;This is your div content&lt;/div&gt;&quot;
        content: function() {
          return $(&#39;#popover-content&#39;).html();
        }
    
        })
        .click(function(e) {
            e.preventDefault();
    });

However, It doesn&#39;t work well on dynamic list. It can show up when I click the button &quot;twice&quot; and only show up one of list items I click fist time. 

MY html: 
   

     &lt;ul id=&quot;project-list&quot; class=&quot;nav nav-list&quot;&gt;
       &lt;li class=&#39;project-name&#39;&gt;
         &lt;a &gt;project name 1
             &lt;button class=&quot;pop-function&quot; rel=&quot;popover&quot; &gt;&lt;/button&gt;
         &lt;/a&gt;
       &lt;/li&gt;
       &lt;li class=&#39;project-name&#39;&gt;
         &lt;a&gt;project name 2
            &lt;button class=&quot;pop-function&quot; rel=&quot;popover&quot; &gt;&lt;/button&gt;
         &lt;/a&gt;
       &lt;/li&gt;
                            
     &lt;/ul&gt;
        
    &lt;div id=&quot;popover-content&quot; style=&quot;display:none&quot;&gt;
        &lt;button class=&quot;pop-sync&quot;&gt;&lt;/button&gt;
        &lt;button class=&quot;pop-delete&quot;&gt;&lt;/button&gt;
    &lt;/div&gt;

My JavaScript for dynamic:

    $(document).on(&quot;click&quot;, &quot;#project-list li&quot; , function(){
       var username = $.cookie(&quot;username&quot;);
       var projectName = $(this).text()
       $(&quot;li.active&quot;).removeClass(&quot;active&quot;);
       $(this).addClass(&quot;active&quot;);
       console.log(&quot;username: &quot; +username + &quot; project name: &quot;+projectName );
    });
    
    
    $(document).on(&quot;click&quot;, &quot;button[rel=popover]&quot;, function(){
    	$(this).popover({ 
    	   placement : &#39;right&#39;,
    	   container : &#39;body&#39;,
    	   html : true,
    	content: function() {
    	   return $(&#39;#popover-content&#39;).html();
        	}
    
        }).click(function(e){
    	e.preventDefault();
        })
    	
    });
    
    
    //for close other popover when one popover button click
    $(document).on(&quot;click&quot;, &quot;button[rel=popover]&quot; , function(){
    
            $(&quot;button[rel=popover]&quot;).not(this).popover(&#39;hide&#39;);
     });

I have searched similar problems, but I still can&#39;t find the one to solve my problem.  If anyone has some ideas, please let me know. Thanks your help. 

How to bind bootstrap popover on dynamic elements

What is the standard way for a blueprint to access the application logger?

In Flask: How to access app Logger within Blueprint

<p>What is the standard way for a blueprint to access the application logger?</p>


I am trying to find a temp directory ,
but when i am trying to get the directory using

    tempfile.gettempdir()

it&#39;s giving me error of

     File &quot;/usr/lib/python2.6/tempfile.py&quot;, line 254, in gettempdir
        tempdir = _get_default_tempdir()
      File &quot;/usr/lib/python2.6/tempfile.py&quot;, line 201, in _get_default_tempdir
        (&quot;No usable temporary directory found in %s&quot; % dirlist))
    IOError: [Errno 2] No usable temporary directory found in [&#39;/tmp&#39;, &#39;/var/tmp&#39;, &#39;/usr/tmp&#39;, &#39;/home/openerp/openerp-server&#39;]

The permission on the directory is 777 owned by root.
 

No usable temporary directory found

I am a Python beginning self-learner, running on MacOS.

I&#39;m making a program with a text parser GUI in tkinter, where you type a command in a `Entry` widget, and hit a `Button` widget, which triggers my `parse()` funct, ect, printing the results to a `Text` widget, text-adventure style.

&gt; \&gt; Circumvent the button
&gt;
&gt; I can&#39;t let you do that, Dave.

I&#39;m trying to find a way to get rid of the need to haul the mouse over to the `Button` every time the user issues a command, but this turned out harder than I thought.

I&#39;m guessing the correct code looks like `self.bind(&#39;&lt;Return&gt;&#39;, self.parse())`? But I don&#39;t even know where to put it. `root`, `__init__`, `parse()`, and `create_widgets()` don&#39;t want it.

To be clear, the only reason anyone should hit enter in the prog is to trigger `parse()`, so it doesn&#39;t need to be espoused to the `Entry` widget specifically. Anywhere it works is fine.

In response to 7stud, the basic format:

    from tkinter import *
    import tkinter.font, random, re
    
    class Application(Frame):
        
        def __init__(self, master):
            Frame.__init__(self, master, ...)
            self.grid()
            self.create_widgets()
            self.start()
    
            
        def parse(self):
            ...
    
    
        def create_widgets(self):
            
            ...
    
            self.submit = Button(self, text= &quot;Submit Command.&quot;, command= self.parse, ...)
            self.submit.grid(...)
    
            
    root = Tk()
    root.bind(&#39;&lt;Return&gt;&#39;, self.parse)
    
    app = Application(root)
    
    root.mainloop()



How do I bind the enter key to a function in tkinter?

I&#39;m trying to figure out how to get `python setup.py test` to run the equivalent of `python -m unittest discover`.  I don&#39;t want to use a run_tests.py script and I don&#39;t want to use any external test tools (like `nose` or `py.test`).  It&#39;s OK if the solution only works on python 2.7.

In `setup.py`, I think I need to add something to the `test_suite` and/or `test_loader` fields in config, but I can&#39;t seem to find a combination that works correctly:

    config = {
        &#39;name&#39;: name,
        &#39;version&#39;: version,
        &#39;url&#39;: url,
        &#39;test_suite&#39;: &#39;???&#39;,
        &#39;test_loader&#39;: &#39;???&#39;,
    }

**Is this possible using only `unittest` built into python 2.7?**

FYI, my project structure looks like this:

    project/
      package/
        __init__.py
        module.py
      tests/
        __init__.py
        test_module.py
      run_tests.py &lt;- I want to delete this
      setup.py

**Update**: This is possible with `unittest2` but I want find something equivalent using only `unittest`

From https://pypi.python.org/pypi/unittest2

&gt; unittest2 includes a very basic setuptools compatible test collector. Specify test_suite = &#39;unittest2.collector&#39; in your setup.py. This starts test discovery with the default parameters from the directory containing setup.py, so it is perhaps most useful as an example (see unittest2/collector.py).

For now, I&#39;m just using a script called `run_tests.py`, but I&#39;m hoping I can get rid of this by moving to a solution that only uses `python setup.py test`.

Here&#39;s the `run_tests.py` I&#39;m hoping to remove:

    import unittest

    if __name__ == &#39;__main__&#39;:
        
        # use the default shared TestLoader instance
        test_loader = unittest.defaultTestLoader
        
        # use the basic test runner that outputs to sys.stderr
        test_runner = unittest.TextTestRunner()
        
        # automatically discover all tests in the current dir of the form test*.py
        # NOTE: only works for python 2.7 and later
        test_suite = test_loader.discover(&#39;.&#39;)
        
        # run the test suite
        test_runner.run(test_suite)

How to run unittest discover from &quot;python setup.py test&quot;?

So I completely understand how to use [resample](http://pandas-docs.github.io/pandas-docs-travis/generated/pandas.DataFrame.resample.html?highlight=dataframe%20resample#pandas.DataFrame.resample), but the documentation does not do a good job explaining the options.

So most options in the `resample` function are pretty straight forward except for these two:

 - rule : the offset string or object representing target conversion
 - how : string, method for down- or re-sampling, default to ‘mean’

So from looking at as many examples as I found online I can see for rule you can do `&#39;D&#39;` for day, `&#39;xMin&#39;` for minutes, `&#39;xL&#39;` for milliseconds, but that is all I could find.

for how I have seen the following: `&#39;first&#39;`, `np.max`, `&#39;last&#39;`, `&#39;mean&#39;`, and `&#39;n1n2n3n4...nx&#39;` where nx is the first letter of each column index.

So is there somewhere in the documentation that I am missing that displays every option for `pandas.resample`&#39;s rule and how inputs? If yes, where because I could not find it. If no, **what are all the options for them?**

pandas resample documentation

Wrote this function in python that transposes a matrix:

    def transpose(m):
    	height = len(m)
    	width = len(m[0])
    	return [ [ m[i][j] for i in range(0, height) ] for j in range(0, width) ]

In the process I realized I don&#39;t fully understand how single line nested for loops execute. Please help me understand by answering the following questions:

 1. What is the order in which this for loop executes?
 2. If I had a triple nested for loop, what order would it execute?
 3. What would be equal the equal unnested for loop?

Given,

    [ function(i,j) for i,j in object ]

 1. What type must object be in order to use this for loop structure?
 2. What is the order in which i and j are assigned to elements in object?
 3. Can it be simulated by a different for loop structure?
 4. Can this for loop be nested with a similar or different structure for loop? And how would it look?

Additional information is appreciated as well.

Single Line Nested For Loops

My current format string is:

    formatter = logging.Formatter(&#39;%(asctime)s : %(message)s&#39;)

and I want to add a new field called `app_name` which will have a different value in each script that contains this formatter.

    import logging
    formatter = logging.Formatter(&#39;%(asctime)s %(app_name)s : %(message)s&#39;)
    syslog.setFormatter(formatter)
    logger.addHandler(syslog)

But I&#39;m not sure how to pass that `app_name` value to the logger to interpolate into the format string. I can obviously get it to appear in the log message by passing it each time but this is messy.

I&#39;ve tried:

    logging.info(&#39;Log message&#39;, app_name=&#39;myapp&#39;)
    logging.info(&#39;Log message&#39;, {&#39;app_name&#39;, &#39;myapp&#39;})
    logging.info(&#39;Log message&#39;, &#39;myapp&#39;)

but none work. 


How do I add custom field to Python log format string?

Let&#39;s say I have the following code:

    import logging
    import logging.handlers
    
    a = logging.getLogger(&#39;myapp&#39;)
    h = logging.handlers.RotatingFileHandler(&#39;foo.log&#39;)
    h.setLevel(logging.DEBUG)
    a.addHandler(h)
    
    # The effective log level is still logging.WARN
    print a.getEffectiveLevel() 
    a.debug(&#39;foo message&#39;)
    a.warn(&#39;warning message&#39;)

I expect that setting `logging.DEBUG` on the handler would cause debug-level messages to be written to the log file. However, this prints 30 for the effective level (equal to `logging.WARNING`, the default), and only logs the `warn` message to the log file, not the debug message.

It appears that the handler&#39;s log level is being dropped on the floor, e.g. it&#39;s silently ignored. Which makes me wonder, why have `setLevel` on the handler at all? 


What is the point of setLevel in a python logging handler?

Ok, here&#39;s the code where I setup everything:

    if __name__ == &#39;__main__&#39;:
        app.debug = False

        applogger = app.logger

        file_handler = FileHandler(&quot;error.log&quot;)
        file_handler.setLevel(logging.DEBUG)

        applogger.setLevel(logging.DEBUG)
        applogger.addHandler(file_handler)
    
        app.run(host=&#39;0.0.0.0&#39;)

What happens is

1. error.log gets created
2. Nothing is ever written to it
3. Despite not adding a StreamHandler and setting debug to false I still get everything to STDOUT (this might be correct, but still seems weird)

Am I totally off here somewhere or what is happening?

Flask logging - Cannot get it to write to a file

I&#39;m working on a Rails 4 project, and I can&#39;t seem to make anything show up in my development log when I call `Rails.logger.debug &quot;test&quot;` I&#39;ve tried searching online but I feel like I haven&#39;t made much progress. How would I go about setting up a logger and telling it to write in my development log file?

Any help would be greatly appreciated. 

Using logger in Rails 4

I am trying to configure log4j2 for my tomcat server running locally.  I am unable to pipe the logs to a location that is relative to the tomcat install.

If I specify an absolute path it works.  If I use a relative path it outputs to the location of `System.getProperty(&quot;user.dir&quot;)`.

But when I try to use either `${catalina.home}` or `${catalina.base}` it does not work. If I output those two system properties on startup, they are defined and point to the proper location.

Also, 

 - Tomcat 7.0.26
 - servlet 2.5
 - log4j2.0 beta 8
 - we are using slf4j with log4j2 behind it.  
 - I setup all loggers to be async through the environment variable `-DLog4jContextSelector=org.apache.logging.log4j.core.async.AsyncLoggerContextSelector`.

My feeling is that Tomcat might not be fully initialized when it processes the log4j2.xml?  Any ideas would be greatly appreciated!

Here is my `log4j2.xml`:


&lt;!-- language: xml --&gt;

    &lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?&gt;
    &lt;configuration status=&quot;debug&quot; name=&quot;LoggingConfig&quot;&gt; 
      &lt;appenders&gt;
        &lt;FastFile name=&quot;ALog&quot; fileName=&quot;${catalina.home}/logs/test.log&quot; immediateFlush=&quot;true&quot; append=&quot;true&quot;&gt;
          &lt;PatternLayout&gt;
            &lt;pattern&gt;%d %p %c{1.} [%t] %m%n&lt;/pattern&gt;
          &lt;/PatternLayout&gt;
        &lt;/FastFile&gt;
      &lt;/appenders&gt;
     
      &lt;loggers&gt;
        &lt;logger name=&quot;a.namespace.dir&quot; level=&quot;info&quot; additivity=&quot;false&quot;&gt;
          &lt;appender-ref ref=&quot;ALog&quot;/&gt;
        &lt;/logger&gt;
     
        &lt;root level=&quot;info&quot;&gt;
          &lt;appender-ref ref=&quot;ALog&quot;/&gt;
        &lt;/root&gt;
      &lt;/loggers&gt;
     
    &lt;/configuration&gt;

From catalina.out

    2013-07-31 11:22:00,313 DEBUG Calling createAppender on class org.apache.logging.log4j.core.appender.FastFileAppender for element FastFile with params(fileName=&quot;${catalina.home}/logs/test.log&quot;, append=&quot;true&quot;, name=&quot;ALog&quot;, immediateFlush=&quot;true&quot;, suppressExceptions=&quot;null&quot;, PatternLayout(%d %p %c{1.} [%t] %m%n), null, advertise=&quot;null&quot;, advertiseURI=&quot;null&quot;, Configuration(LoggingConfig))
    
    2013-07-31 11:22:00,315 DEBUG Starting FastFileManager ${catalina.home}/logs/test.log
    
    2013-07-31 11:22:00,316 DEBUG Calling createAppenders on class org.apache.logging.log4j.core.config.plugins.AppendersPlugin for element appenders with params(appenders={ALog})
    
    2013-07-31 11:22:00,317 DEBUG Generated plugins in 0.000016000 seconds
    
    2013-07-31 11:22:00,318 DEBUG Calling createAppenderRef on class org.apache.logging.log4j.core.config.AppenderRef for element appender-ref with params(ref=&quot;ALog&quot;, level=&quot;null&quot;, null)
    
    2013-07-31 11:22:00,320 DEBUG Calling createLogger on class org.apache.logging.log4j.core.config.LoggerConfig for element logger with params(additivity=&quot;false&quot;, level=&quot;info&quot;, name=&quot;a.namespace.dir&quot;, includeLocation=&quot;null&quot;, appender-ref={org.apache.logging.log4j.core.config.AppenderRef@6e8ef177}, properties={}, Configuration(LoggingConfig), null)
    
    2013-07-31 11:22:00,321 DEBUG Calling createAppenderRef on class org.apache.logging.log4j.core.config.AppenderRef for element appender-ref with params(ref=&quot;ALog&quot;, level=&quot;null&quot;, null)
    
    2013-07-31 11:22:00,322 DEBUG Calling createLogger on class org.apache.logging.log4j.core.config.LoggerConfig$RootLogger for element root with params(additivity=&quot;null&quot;, level=&quot;info&quot;, includeLocation=&quot;null&quot;, appender-ref={org.apache.logging.log4j.core.config.AppenderRef@6a8ef455}, properties={}, Configuration(LoggingConfig), null)
    
    2013-07-31 11:22:00,323 DEBUG Calling createLoggers on class org.apache.logging.log4j.core.config.plugins.LoggersPlugin for element loggers with params(loggers={a.namespace.dir, root})

log4j2 specify relative path to tomcat home dir for FileAppender

In flask, I can do this:

    render_template(&quot;foo.html&quot;, messages={&#39;main&#39;:&#39;hello&#39;})

And if foo.html contains `{{ messages[&#39;main&#39;] }}`, the page will show `hello`. But what if there&#39;s a route that leads to foo:

    @app.route(&quot;/foo&quot;)
    def do_foo():
        # do some logic here
        return render_template(&quot;foo.html&quot;)

In this case, the only way to get to foo.html, if I want that logic to happen anyway, is through a `redirect`:

    @app.route(&quot;/baz&quot;)
    def do_baz():
        if some_condition:
            return render_template(&quot;baz.html&quot;)
        else:
            return redirect(&quot;/foo&quot;, messages={&quot;main&quot;:&quot;Condition failed on page baz&quot;}) 
            # above produces TypeError: redirect() got an unexpected keyword argument &#39;messages&#39;

So, how can I get that `messages` variable to be passed to the `foo` route, so that I don&#39;t have to just rewrite the same logic code that that route computes before loading it up?

redirect while passing arguments

Does anyone know why I can&#39;t overwrite an existing endpoint function if i have two url rules like this

    app.add_url_rule(&#39;/&#39;,
                     view_func=Main.as_view(&#39;main&#39;),
                     methods=[&quot;GET&quot;])
    
    app.add_url_rule(&#39;/&lt;page&gt;/&#39;,
                     view_func=Main.as_view(&#39;main&#39;),
                     methods=[&quot;GET&quot;])

Traceback:

    Traceback (most recent call last): 
      File &quot;demo.py&quot;, line 20, in &lt;module&gt; methods=[&quot;GET&quot;]) 
      File &quot;.../python2.6/site-packages/flask‌​/app.py&quot;, 
        line 62, in wrapper_func return f(self, *args, **kwargs) 
      File &quot;.../python2.6/site-packages/flask‌​/app.py&quot;, 
        line 984, in add_url_rule &#39;existing endpoint function: %s&#39; % endpoint)  
    AssertionError: View function mapping is overwriting an existing endpoint 
        function: main


AssertionError: View function mapping is overwriting an existing endpoint function: main

How are you meant to debug errors in Flask?  Print to the console?  Flash messages to the page?  Or is there a more powerful option available to figure out what&#39;s happening when something goes wrong?

How to debug a Flask app

I am getting `working outside of request context` when trying to access `session` in a test.  How can I set up a context when I&#39;m testing something that requires one?

    import unittest
    from flask import Flask, session
    
    app = Flask(__name__)
    
    @app.route(&#39;/&#39;)
    def hello_world():
        t = Test()
        hello = t.hello()
        return hello
    
    class Test:
        def hello(self):
            session[&#39;h&#39;] = &#39;hello&#39;
            return session[&#39;h&#39;]

    class MyUnitTest(unittest.TestCase):
        def test_unit(self):
            t = tests.Test()
            t.hello()


Testing code that requires a Flask app or request context

I already have an existing Database that has a lot of tables and a lot of data in `MySQL`. I intend to create a `Flask` app and use sqlalchemy along with it. Now I asked out on irc and looked around on google and tried the following ideas:

**First** I used [sqlacodegen][1] to generate the models from my `DB`. But then I was confused about it a little and looked some more. And I found [this][2].

This looked like an elegant solution.

So **Second**, I rewrote my `models.py` according to the solution there and now I am even more confused. I am looking for the best approach to build this flask app along with the already existing DB. 

I looked into the flask documentation but didnt really get any help for a project with an already existing db. There is a lot of good stuff for creating something from scratch, creating the db and all. But I am really confused.

Please Note that its my first day with `Flask`, but I have experience with `Django`, so the basic concepts are not a hurdle. I need some guidance in choosing the best approach for this usecase. A detailed explanation would be greatly appreciated. By detailed I definitely do not expect someone to write all the code and spoon feed me on this, but just enough to get me started, that is integrate this db seamlessly into `flask` via `sqlalchemy`. Note my DB is in `MySQL`.


  [1]: https://pypi.python.org/pypi/sqlacodegen
  [2]: http://flask.pocoo.org/mailinglist/archive/2012/5/23/flask-sqlalchemy-with-pre-existing-database/#9974419419ee1960c88c98689f6aee9d

Content Type	Original Author	Original Content on Stackoverflow
Question	Gal Bracha	View Question on Stackoverflow
Solution 1 - Python	Gal Bracha	View Answer on Stackoverflow
Solution 2 - Python	suzanshakya	View Answer on Stackoverflow

In Flask: How to access app Logger within Blueprint

Python Problem Overview

Python Solutions

Solution 1 - Python

Solution 2 - Python

How to bind bootstrap popover on dynamic elements

How to implement O(logn) decrease-key operation for min-heap based Priority Queue?

Attributions