IronPython in Action offers a comprehensive, hands-on introduction to . He maintains the IronPython Cookbook and IronPython-URLs websites, and can also. Using logging in multiple modulesĀ¶. Multiple calls to ger(‘ someLogger’) return a reference to the same logger object. This is true not only within. Website for the IronPython in Action book. IronPython Cookbook You can use the code ironpython35 for a 35% discount off IronPython in Action from.

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This page contains a number of recipes related to logging, which have been found useful in the past.

Multiple calls to logging. This is true not only within the same module, but also across modules as long as it is in the same Python interpreter process. It is true for references to the same object; additionally, iron;ython code can define and configure a parent logger in one module and create but not configure a child logger in a separate module, and all logger calls to the child will pass up to the parent. Here is a main module:.

MonthCalendar Control and datetime

Loggers are plain Python objects. The addHandler method has no minimum or maximum quota for the number of handlers you may add. Sometimes it will be beneficial for an application to log all messages of all severities to a text file while simultaneously logging errors or above to the console. To set this up, simply configure the appropriate handlers. The logging calls in the application code will remain vookbook. Here is a slight modification to the previous simple module-based configuration example:.

All that changed was the addition and configuration of a new handler named fh.

The ability to create new handlers with higher- or lower-severity filters can be very helpful when writing and testing an application. Instead of using many print statements for debugging, use logger.

Unlike the print statements, which you will have to delete or comment out later, the logger. The other messages are sent to both destinations. This example uses console and file handlers, but you can use any number and combination of handlers you choose. And here is a script that takes a filename and sends that file to the server, properly preceded with the binary-encoded length, as the new logging configuration:.

XAML GUI Events Example – IronPython Cookbook

A simple way of doing this is attaching a SocketHandler instance to the root logger at the sending end:. At the receiving end, you can set up a receiver using the socketserver module. Here is a basic working example:.

First run the server, and then the client. On the client side, nothing ironpythom printed on the console; on the server side, you should see something like:. Note that there are some security issues with pickle in some scenarios. If these affect you, you can use an alternative serialization scheme by overriding the makePickle method and implementing your alternative there, as well as adapting the above script to use your alternative serialization.


Sometimes you want logging output to dookbook contextual information in addition to the parameters passed to the logging call. For example, in a networked application, it may be desirable to log client-specific information in the log e. While it might be tempting to create Logger instances on a per-connection basis, this is not a good idea because these instances are not garbage collected.

While this is not a problem in practice, when the number of Logger instances is dependent on the level of granularity you want to use in logging an application, it could be hard to manage if the number of Logger instances becomes effectively unbounded.

An easy way in which you can pass contextual information to be output along with logging event information is to use the LoggerAdapter class. This class is designed to look like a Loggerso that you can call debuginfowarningerrorexceptioncritical and log. These methods have the same signatures as their counterparts in Loggerso you can use the two types of instances interchangeably.

Ironpythin you create an instance of LoggerAdapteryou pass it a Logger instance and a dict-like object which contains your contextual information.

When you call one of the logging methods on an instance of LoggerAdapterit delegates the call to the underlying instance of Logger passed to its constructor, and arranges to pass cokbook contextual information in the delegated call.

The process method of LoggerAdapter is where the contextual information is added to the logging output. If you need a different method, e. You can also add contextual information to log output using a user-defined Filter. Filter instances are allowed to modify the LogRecords passed to them, including adding additional attributes which can then be output using a suitable format string, or if needed a custom Formatter.

For example in a web application, the request being processed or at least, the interesting parts of it can be stored in a threadlocal threading. In that case, the same format string can be used to get similar output to that ironpythoon above. Although logging is thread-safe, and logging to a single file from multiple threads in a single process is supported, logging to a single file from multiple processes is not supported, because there is no standard way to serialize access to a single file across multiple processes in Python.

If you need cookboook log to a single file from multiple processes, one way of doing this is to have all the processes log to a SocketHandlerand have a separate process which implements a socket server which reads from the socket and logs to file.

If you prefer, you can dedicate one thread in one of the existing processes to perform this function. The following section documents this approach in more detail and includes a working socket receiver which can be used as a starting point for you to adapt in your own applications.


If you are ironpytjon a recent version of Python which includes the multiprocessing module, you could write your own handler which uses the Lock class from this module to serialize access to the file from your processes.

The existing FileHandler and fookbook do not make use of multiprocessing at present, though they may do so in the future. Note that at present, the multiprocessing module does not provide working lock functionality on all platforms see http: Sometimes you want to let a log file grow to a certain size, then open a new file and log to that.

You may want to keep a certain number of these files, and when that many files have been created, rotate the files so that the number of files and the size of the files both remain bounded. For this usage pattern, the logging package provides a RotatingFileHandler:. Each of the existing backup files is renamed to increment the suffix. Obviously this example sets the log length much much too small as an extreme example. You would want to set maxBytes to an appropriate value.

Whetting Your Appetite 2. Using the Python Interpreter 3. An Informal Introduction to Python 4. More Control Flow Tools 5. Input and Output 8. Errors and Exceptions 9. Ironpythno Tour of the Ccookbook Library Interactive Input Editing and History Substitution Issues and Limitations Python Setup and Usage 1. Command line and environment 2. Using Python on Unix platforms 3. Using Python on Windows 4. Non-essential Built-in Functions 4. Numeric and Mathematical Modules File and Directory Access Data Compression and Archiving Generic Operating System Services Optional Operating System Services Interprocess Communication and Networking Internet Data Handling Structured Markup Processing Tools Internet Protocols and Support Graphical User Interfaces with Tk Debugging and Profiling Python Runtime Services Custom Python Interpreters Python Language Services Python compiler package MS Windows Specific Services Unix Specific Services Mac OS X specific services SunOS Specific Services Defining New Types 3.

Extending IronPython with C 2. Parsing and Tokenizing Distributing Python Modules 1. An Introduction to Distutils 2. Writing the Setup Script 3.

Writing the Setup Configuration File 4. Creating a Source Distribution 5. Creating Built Distributions 6. Registering with the Package Index 7.

Uploading Packages to the Package Index 8. Tips and Tricks Documenting Python 1. Additional Markup Constructs 5. Differences to the LaTeX markup 6. Here is a main module: