Debug your application using logs, applying best practices, application insights, KQL and Snapshot debugger

1. How to become an Expert at Debugging .Net
Application
Karthikeyan VK
Karthik_3030@yahoo.com
@karthik3030
https://blogs.karthikeyanvk.in

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Why Should you be better @ debugging?
Life is stress free, when we know why the issue occurs.
Life is better, when we know what is causing the issue.
Life becomes easier, when we know how to reproduce the issue.
Good Debugging skills helps us with all the above.
https://blogs.karthikeyanvk.in

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Mindset of great Debugger
Open Mindset.
Thinking small
Marathon.
Back to Square one - Anytime
Walking Away
https://blogs.karthikeyanvk.in

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Open Mindset
If your mind is empty, it is always ready for anything, it is open to
everything.
In the beginner's mind there are many possibilities, but in the
expert's mind there are few.
https://blogs.karthikeyanvk.in

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Open Mindset
No conceived notion.
Leave all your previous knowledge and just approach every
problem as a new problem
Listen to anyone, who has already investigated, don’t reject.
https://blogs.karthikeyanvk.in

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Thinking Small - Mindset
Try to divide the changes that caused into chunks, in your mind
Divide the problem into smaller junks in your mind.
Brainstorm the smaller junks with your colleague, especially non-
technical person.
https://blogs.karthikeyanvk.in

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Marathon Mindset
It’s a marathon, Not a sprint.
Specifying any time constraint will only hinder the possibilities
Don’t run into the debugger.
Try to talk through the problem
Read & analyze the code that may have caused the problem
https://blogs.karthikeyanvk.in

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Marathon Mindset
Make sure you understood the problem before debugging.
If any stakeholder(s) pressures you, try to work out of their sight.
Don’t commit anytime.
https://blogs.karthikeyanvk.in

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Back to square one -Mindset
Always be ready to ditch all your current investigation.
Learn to start from the scratch, anytime.
Never get into a rabbit hole, always be ready to climb up at any
time.
Make sure your tools helps you go back to square one at any
point of time.
https://blogs.karthikeyanvk.in

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Walkaway - Mindset
Learn to walk away from debugging.
It can be walking to water cooler for a break.
Going home and having a nice sleep.
Not touching the issue for a day or so.
https://blogs.karthikeyanvk.in

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Tools for Debugging
Visual Studio – Who can beat this !!
Resharper.
RevDebug.
dotPeek.
dotTrace.
https://blogs.karthikeyanvk.in

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Why Logging
Good logs helps to travel in time.
Good Logs helps to see the past.
Helps in troubleshooting problem.
Identify infrastructure problem.
Verify our application is working.
https://blogs.karthikeyanvk.in

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Best Practices - Logging
Don’t reinvent the wheel. Use any logging framework.
Log at proper level – Trace, Debug, Error.
Implement Correlation-id
Easy to read and understand.
Also Write it in a way machine can understand.
User plays: {'user':1334563, 'card':'4 of spade', 'game':23425656}
https://blogs.karthikeyanvk.in

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Best Practices - Logging
Avoid Vendor Lock-in – Abstract your logging code.
Use side care pattern for logging.
Also think Logging for auditing, statistics and profiling
Never log sensitive data like password etc.
https://blogs.karthikeyanvk.in

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Why Application Insights
Used to monitor your live applications.
It will automatically detect performance anomalies, and includes
powerful analytics tools to help you diagnose issues and to
understand what users actually do with your app
https://blogs.karthikeyanvk.in

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Why Application Insights ?
Works for apps on a wide variety of platforms including .NET,
Node.js and Java EE, hosted on-premises, hybrid, or any public
cloud.
Integrates with your DevOps process
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What is Application Insights ?
Application Insights is an extensible Application Performance
Management (APM) service for developers and DevOps
professionals.
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What is Application Insights ?
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What does app insight monitor?
https://blogs.karthikeyanvk.in
Request rates, response times, and failure rates
Dependency rates, response times, and failure rates
Exceptions
Page views and load performance
Custom events and metrics
….

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@karthik3030
DEMO
APPINSIGHTS
https://blogs.karthikeyanvk.in

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Why KQL ?
KQL helps in data-flow model designed to make the syntax easy
to read, author, and automate.
Used to query logs in application insights.
The query uses schema entities that are organized in a hierarchy
similar to SQL's: databases, tables, and columns.
https://blogs.karthikeyanvk.in

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What is KQL ?
A Kusto query is a read-only request to process data and return
results.
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@karthik3030
DEMO
KQL
https://blogs.karthikeyanvk.in

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Why Snapshot Debugger ?
When exception happens snapshot shows the state of source
code and variables at the moment the exception was thrown.
Snapshot Debugger in Azure Application Insights monitors
exception telemetry from your web app / Function app.
https://blogs.karthikeyanvk.in

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Why Snapshot Debugger ?
It collects snapshots on your top-throwing exceptions so that you
have the information you need to diagnose issues in production.
You can view debug snapshots in the portal to see the call stack
and inspect variables at each call stack frame.
Get access to the variable
https://blogs.karthikeyanvk.in

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What is Snapshot Debugger ?
Snapshot debugger helps in debugging your application with the
state of source code and variables at the moment the exception
was thrown.
Takes a quick fork and get the copy of process page table.
Will not slow your production while debug.
https://blogs.karthikeyanvk.in

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@karthik3030
DEMO
Snapshot Debugger
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Settings to remember
Visual studio 2017 and above
.NET Framework and ASP.NET applications running .NET
Framework 4.5 or later.
.NET Core 2.0 and ASP.NET Core 2.0 applications running on
Windows.
Linux app not supported yet.
https://blogs.karthikeyanvk.in

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Settings to remember
Access to snapshots is protected by role-based access control
(RBAC). To inspect a snapshot, you must first be added to the
necessary role by a subscription owner.
Make sure you install the extension for Snapshot Debugger
Function app, enable snapshot debugger in host.json
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@karthik3030
DEMO
Snapshot
Debugger
https://blogs.karthikeyanvk.in

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References
@karthik3030
• https://www.amazon.in/Zen-Mind-Beginners-Shunryu-Suzuki/dp/1590308492
• https://www.jetbrains.com/resharper/features/debugging_assistance.htm
• https://www.scalyr.com/blog/the-10-commandments-of-logging/
• https://docs.microsoft.com/en-us/azure/azure-monitor/app/snapshot-debugger
• https://marketplace.visualstudio.com/items?itemName=ms-
appinsights.appinsightsreleaseannotations
• https://docs.microsoft.com/en-us/azure/data-explorer/kusto/query/sqlcheatsheet
https://blogs.karthikeyanvk.in

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Networking and more
@karthik3030
• https://www.facebook.com/aspiringDotnetArchitects/
• https://www.meetup.com/Chennai-Microsoft-Azure-User-Group/
• https://www.youtube.com/channel/UCJxa58lDcDj4tYQIHh7ORxA
https://blogs.karthikeyanvk.in

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@karthik3030
Thank you
/Q&A
https://blogs.karthikeyanvk.in