Blazor Client Side (WASM) Application Insights - azure-application-insights

Question

Does Application Insights SDK work for Blazor WASM?
I'm trying connect my application but it doesn't send any metrics. Even when instantiating TelemetryClient it's simply hanging.

Answer 1

Unlike Blazor Server-side, you can't just add a singleton into IoC and then inject it to pages. The first thing I tried was this way too! I know, that should be the way... Blazor team needs to handle this behind the scene I think.
But anyway, here is what you should do:
Our approach will assume that we will use the Application Insight javascript SDK.
Copy the snippet mentioned on here: https://learn.microsoft.com/en-us/azure/azure-monitor/app/javascript#snippet-based-setup
(if you are too lazy, find below)
<script type="text/javascript">
!function(T,l,y){var S=T.location,u="script",k="instrumentationKey",D="ingestionendpoint",C="disableExceptionTracking",E="ai.device.",I="toLowerCase",b="crossOrigin",w="POST",e="appInsightsSDK",t=y.name||"appInsights";(y.name||T[e])&&(T[e]=t);var n=T[t]||function(d){var g=!1,f=!1,m={initialize:!0,queue:[],sv:"4",version:2,config:d};function v(e,t){var n={},a="Browser";return n[E+"id"]=a[I](),n[E+"type"]=a,n["ai.operation.name"]=S&&S.pathname||"_unknown_",n["ai.internal.sdkVersion"]="javascript:snippet_"+(m.sv||m.version),{time:function(){var e=new Date;function t(e){var t=""+e;return 1===t.length&&(t="0"+t),t}return e.getUTCFullYear()+"-"+t(1+e.getUTCMonth())+"-"+t(e.getUTCDate())+"T"+t(e.getUTCHours())+":"+t(e.getUTCMinutes())+":"+t(e.getUTCSeconds())+"."+((e.getUTCMilliseconds()/1e3).toFixed(3)+"").slice(2,5)+"Z"}(),iKey:e,name:"Microsoft.ApplicationInsights."+e.replace(/-/g,"")+"."+t,sampleRate:100,tags:n,data:{baseData:{ver:2}}}}var h=d.url||y.src;if(h){function a(e){var t,n,a,i,r,o,s,c,p,l,u;g=!0,m.queue=[],f||(f=!0,t=h,s=function(){var e={},t=d.connectionString;if(t)for(var n=t.split(";"),a=0;a<n.length;a++){var i=n[a].split("=");2===i.length&&(e[i[0][I]()]=i[1])}if(!e[D]){var r=e.endpointsuffix,o=r?e.location:null;e[D]="https://"+(o?o+".":"")+"dc."+(r||"services.visualstudio.com")}return e}(),c=s[k]||d[k]||"",p=s[D],l=p?p+"/v2/track":config.endpointUrl,(u=[]).push((n="SDK LOAD Failure: Failed to load Application Insights SDK script (See stack for details)",a=t,i=l,(o=(r=v(c,"Exception")).data).baseType="ExceptionData",o.baseData.exceptions=[{typeName:"SDKLoadFailed",message:n.replace(/\./g,"-"),hasFullStack:!1,stack:n+"\nSnippet failed to load ["+a+"] -- Telemetry is disabled\nHelp Link: https://go.microsoft.com/fwlink/?linkid=2128109\nHost: "+(S&&S.pathname||"_unknown_")+"\nEndpoint: "+i,parsedStack:[]}],r)),u.push(function(e,t,n,a){var i=v(c,"Message"),r=i.data;r.baseType="MessageData";var o=r.baseData;return o.message='AI (Internal): 99 message:"'+("SDK LOAD Failure: Failed to load Application Insights SDK script (See stack for details) ("+n+")").replace(/\"/g,"")+'"',o.properties={endpoint:a},i}(0,0,t,l)),function(e,t){if(JSON){var n=T.fetch;if(n&&!y.useXhr)n(t,{method:w,body:JSON.stringify(e),mode:"cors"});else if(XMLHttpRequest){var a=new XMLHttpRequest;a.open(w,t),a.setRequestHeader("Content-type","application/json"),a.send(JSON.stringify(e))}}}(u,l))}function i(e,t){f||setTimeout(function(){!t&&m.core||a()},500)}var e=function(){var n=l.createElement(u);n.src=h;var e=y[b];return!e&&""!==e||"undefined"==n[b]||(n[b]=e),n.onload=i,n.onerror=a,n.onreadystatechange=function(e,t){"loaded"!==n.readyState&&"complete"!==n.readyState||i(0,t)},n}();y.ld<0?l.getElementsByTagName("head")[0].appendChild(e):setTimeout(function(){l.getElementsByTagName(u)[0].parentNode.appendChild(e)},y.ld||0)}try{m.cookie=l.cookie}catch(p){}function t(e){for(;e.length;)!function(t){m[t]=function(){var e=arguments;g||m.queue.push(function(){m[t].apply(m,e)})}}(e.pop())}var n="track",r="TrackPage",o="TrackEvent";t([n+"Event",n+"PageView",n+"Exception",n+"Trace",n+"DependencyData",n+"Metric",n+"PageViewPerformance","start"+r,"stop"+r,"start"+o,"stop"+o,"addTelemetryInitializer","setAuthenticatedUserContext","clearAuthenticatedUserContext","flush"]),m.SeverityLevel={Verbose:0,Information:1,Warning:2,Error:3,Critical:4};var s=(d.extensionConfig||{}).ApplicationInsightsAnalytics||{};if(!0!==d[C]&&!0!==s[C]){method="onerror",t(["_"+method]);var c=T[method];T[method]=function(e,t,n,a,i){var r=c&&c(e,t,n,a,i);return!0!==r&&m["_"+method]({message:e,url:t,lineNumber:n,columnNumber:a,error:i}),r},d.autoExceptionInstrumented=!0}return m}(y.cfg);(T[t]=n).queue&&0===n.queue.length&&n.trackPageView({})}(window,document,{
src: "https://az416426.vo.msecnd.net/scripts/b/ai.2.min.js", // The SDK URL Source
//name: "appInsights", // Global SDK Instance name defaults to "appInsights" when not supplied
//ld: 0, // Defines the load delay (in ms) before attempting to load the sdk. -1 = block page load and add to head. (default) = 0ms load after timeout,
//useXhr: 1, // Use XHR instead of fetch to report failures (if available),
//crossOrigin: "anonymous", // When supplied this will add the provided value as the cross origin attribute on the script tag
cfg: { // Application Insights Configuration
instrumentationKey: "YOUR_INSTRUMENTATION_KEY_GOES_HERE"
/* ...Other Configuration Options... */
}});
</script>
Copy above code into index.html in <head>, ideally before link and script tags
Next, you need to inject IJSRuntime to call JavaScript methods from .Net code.
Inject it like this on top of the page:
#inject IJSRuntime _jsRuntime
Then you can call whatever Application Insight methods you want via like this:
await _jsRuntime.InvokeVoidAsync("appInsights.trackPageView");
You can find the full list of methods for AI JS SDK here:
https://github.com/microsoft/ApplicationInsights-JS/blob/master/API-reference.md
if you don't want to deal with JSRuntime, #IvanJosipovic created a BlazorApplicationInsight library that wraps everything for you.
Simply follow the instructions on his readme file: https://github.com/IvanJosipovic/BlazorApplicationInsights
Sample telemetry results from my Blazor WebAssembly project:
Hope it helps 🤞