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<!DOCTYPE html>

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<title>Debugging - Full Stack Python</title>

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<h1>Debugging</h1>

<p>Developers often find themselves in situations where the code they've written

is not working quite right. When that happens, a developer debugs their code

by instrumenting, executing and inspecting the code to determine what state

of the application does not match the assumptions of how the code should

be correctly running.</p>

<h2>Why is debugging important?</h2>

<p>There are bugs in every modest sized or larger application. Every

developer has to learn how to debug code in order to write programs that

work as correctly as time and budget allow.</p>

<h3>Debugging resources</h3>

<ul>

<li>

<p><a href="http://howchoo.com/g/zgi2y2iwyze/debugging-your-python-code">Debugging your Python code</a>

walks through a scenario where

can be used to find a defect in a block of Python code.</p>

</li>

<li>

<p><a href="https://pymotw.com/2/pdb/">pdb - Interactive Debugger</a> is featured on

the Python Module of the Week blog and has some great detail on using

the program effectively.</p>

</li>

<li>

<p><a href="http://blog.ionelmc.ro/2013/06/05/python-debugging-tools/">Python debugging tools</a>

provides a list of tools such as pdb and its derivatives ipdb, pudb and

pdb++ along with how they can be used in the hunt for defects.</p>

</li>

<li>

<p><a href="https://pythonconquerstheuniverse.wordpress.com/2009/09/10/debugging-in-python/">Debugging in Python</a>

elaborates on what pdb does and how it can be used.</p>

</li>

</ul>

<h3>What's next after testing your application?</h3>

<p class="under-btn">What code metrics should I be aware of?</p> </div>

</div>

<p class="under-btn">Can I automate testing and deployments for my app?</p> </div>

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<p class="under-btn">How do I create unit tests?</p> </div>

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<h4>Sign up here to receive a monthly email with major updates to this site, tutorials and discount codes for Python books.</h4>

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<p style="font-size: .8em; margin-top: 10px;">Searching for a complete, step-by-step deployment walkthrough? Learn more about <a href="http://www.deploypython.com/">The Full Stack Python Guide to Deployments book</a>.

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<h5>Sign up to get a monthly email with Python tutorials and major updates to this site.</h5>

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<h3 class="panel-head"><a href="/table-of-contents.html" style="color: #fff;">Table of Contents</a></h3>

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<a href="/introduction.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif;'>1. Introduction</a><a href="/learning-programming.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Learning Programming</a><a href="/why-use-python.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Why Use Python?</a><a href="/python-2-or-3.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Python 2 or 3?</a><a href="/enterprise-python.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Enterprise Python</a><a href="/best-python-resources.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Best Python Resources</a><a href="/best-python-videos.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Best Python Videos</a><a href="/development-environments.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif;'>2. Development Environments</a><a href="/vim.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Vim</a><a href="/emacs.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Emacs</a><a href="/python-programming-language.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif;'>3. Core Language</a><a href="/generators.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Generators</a><a href="/comprehensions.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Comprehensions</a><a href="/web-development.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif;'>4. Web Development</a><a href="/web-frameworks.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Web Frameworks</a><a href="/django.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Django</a><a href="/flask.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Flask</a><a href="/bottle.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Bottle</a><a href="/pyramid.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Pyramid</a><a href="/morepath.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Morepath</a><a href="/other-web-frameworks.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Other Web Frameworks</a><a href="/web-design.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Web Design</a><a href="/cascading-style-sheets.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Cascading Style Sheets (CSS)</a><a href="/javascript.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>JavaScript</a><a href="/websockets.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>WebSockets</a><a href="/template-engines.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Template Engines</a><a href="/web-application-security.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Web Application Security</a><a href="/static-site-generator.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Static Site Generators</a><a href="/jinja2.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Jinja2</a><a href="/data.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif;'>5. Data</a><a href="/databases.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Relational Databases</a><a href="/no-sql-datastore.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>NoSQL Data Stores</a><a href="/object-relational-mappers-orms.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Object-relational Mappers</a><a href="/postgresql.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>PostgreSQL</a><a href="/mysql.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>MySQL</a><a href="/sqlite.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>SQLite</a><a href="/application-programming-interfaces.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif;'>6. Web APIs</a><a href="/api-integration.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>API Integration</a><a href="/api-creation.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>API Creation</a><a href="/deployment.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif;'>7. Deployment</a><a href="/servers.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Servers</a><a href="/platform-as-a-service.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Platform-as-a-Service</a><a href="/operating-systems.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Operating Systems</a><a href="/web-servers.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Web Servers</a><a href="/wsgi-servers.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>WSGI Servers</a><a href="/source-control.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Source Control</a><a href="/application-dependencies.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Application Dependencies</a><a href="/static-content.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Static Content</a><a href="/task-queues.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Task Queues</a><a href="/configuration-management.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Configuration Management</a><a href="/continuous-integration.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Continuous Integration</a><a href="/logging.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Logging</a><a href="/monitoring.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Monitoring</a><a href="/web-analytics.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Web Analytics</a><a href="/docker.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Docker</a><a href="/caching.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Caching</a><a href="/microservices.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Microservices</a><a href="/devops.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>DevOps</a><a href="/nginx.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Nginx</a><a href="/apache-http-server.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Apache HTTP Server</a><a href="/caddy.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Caddy</a><a href="/green-unicorn-gunicorn.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Green Unicorn (Gunicorn)</a><a href="/testing.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif;'>8. Testing</a><a href="/unit-testing.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Unit Testing</a><a href="/integration-testing.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Integration Testing</a><a href="/code-metrics.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Code Metrics</a><a href="/debugging.html" class="list-group-item smaller-item active" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Debugging</a><a href="/bots.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>9. Bots</a><a href="/what-full-stack-means.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif;'>9. Meta</a><a href="/change-log.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Change Log</a><a href="/future-directions.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>Future Directions</a><a href="/about-author.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",sans-serif; padding-left: 27px;'>About the Author</a> <a href="/table-of-contents.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",san-serif;background-color:#22B24C; color: #fff;'>...or <span style="border-bottom: 1px dotted;">view the full table of contents</span>.</a>

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<div class="panel-heading"><h3 class="panel-head">Debugging</h3></div>

Major updates are tweeted via

<a href="https://twitter.com/fullstackpython">@fullstackpython</a>.

<hr/>

Need more detailed tutorials than you see here?

<a href="http://www.deploypython.com/">Learn more about The Full Stack Python Guide to Deployments book.</a>

</div>

<h3 class="panel-head"><a href="/table-of-contents.html" style="color: #fff;">Chapters</a></h3>

</div>

<a href="/introduction.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>1. Introduction</a><a href="/development-environments.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>2. Development Environments</a><a href="/python-programming-language.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>3. Core Language</a><a href="/web-development.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>4. Web Development</a><a href="/data.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>5. Data</a><a href="/application-programming-interfaces.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>6. Web APIs</a><a href="/deployment.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>7. Deployment</a><a href="/testing.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>8. Testing</a> <a href="/debugging.html" class="list-group-item smaller-item active" style='font-family: "Helvetica Neue",sans-serif;'>» Debugging</a>

<a href="/what-full-stack-means.html" class="list-group-item smaller-item " style='font-family: "Helvetica Neue",sans-serif;'>9. Meta</a> <a href="/table-of-contents.html" class="list-group-item smaller-item" style='font-family: "Helvetica Neue",san-serif;background-color:#22B24C; color: #fff;'>...or <span style="border-bottom: 1px dotted;">view the full table of contents</span>.</a>

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<a href="http://www.mattmakai.com/" class="underline">Matt Makai</a>

2016

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