Application Insights is a free service to monitor your web and desktop applications. It also provides a nice way to query data using a very comprehensive syntax.
Configure Application Insights
First, you need to add Application Insights to your web application. It should take about 1 minute with Visual Studio 2017:
Then, select your azure account and Visual Studio will do everything for you!
Search for 404 errors
Let's open the analytics tool:
The query editor is very convenient. You can easely write queries with a syntax similar to F#. And, what about the awesome auto-completion in the browser!
Now, you can execute your first query. Let's start with a basic query that search requests with a result code equals to 404:
requests | where resultCode == 404
The result is hard to process. There are php files and duplicate urls, plus rows are not sorted. Let's improve the query with some pipes:
requests | where resultCode == 404 | where url !endswith ".php" // Exclude php files | where timestamp > ago(1d) // Get result of the last day | order by timestamp desc // the last 404 first | distinct url // avoid duplicate urls
The resuls are much easier to process. But, which 404 should you fix first? I think you should start by the most requested 😃 So, let's use the
summarize function to group the data and apply an aggregation function:
requests | where resultCode == 404 | where url !endswith ".php" | where timestamp > ago(1d) | summarize count() by url // Group by url and display the number of item of each group | order by count_ desc
Here's the result 😃