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[BUG] ld: -1 does not block page load

See original GitHub issue

Description/Screenshot Setting ld to -1 does not appear to block the page load, which is causing SDK load failures for us due to conflicts with a script file that should be loaded after App Insights. ld: -1 does not block Notice how loader.js is loaded before ai.2.min.js, even though loader.js is called in the body.

Steps to Reproduce

Set ld: -1
Add some scripts into the body
Reload the page

OS/Browser: Edge Version 98.0.1108.15 (Official build) dev (64-bit)
SDK Version [e.g. 22]: Uh…how do I find this?
How you initialized the SDK: JavaScript snippet

Expected behavior ai.2.min.js loads before any other scripts or styles.

Additional context This is a hosted Blazor WASM app. Here is a full index.html, with the only extra package being BlazorMonaco:

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no" />
    <title>AITest</title>
    <base href="/" />
    <script type="text/javascript">
    !function(T,l,y){var S=T.location,k="script",D="instrumentationKey",C="ingestionendpoint",I="disableExceptionTracking",E="ai.device.",b="toLowerCase",w="crossOrigin",N="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:"5",version:2,config:d};function v(e,t){var n={},a="Browser";return n[E+"id"]=a[b](),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,u,p,l;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][b]()]=i[1])}if(!e[C]){var r=e.endpointsuffix,o=r?e.location:null;e[C]="https://"+(o?o+".":"")+"dc."+(r||"services.visualstudio.com")}return e}(),c=s[D]||d[D]||"",u=s[C],p=u?u+"/v2/track":d.endpointUrl,(l=[]).push((n="SDK LOAD Failure: Failed to load Application Insights SDK script (See stack for details)",a=t,i=p,(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)),l.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,p)),function(e,t){if(JSON){var n=T.fetch;if(n&&!y.useXhr)n(t,{method:N,body:JSON.stringify(e),mode:"cors"});else if(XMLHttpRequest){var a=new XMLHttpRequest;a.open(N,t),a.setRequestHeader("Content-type","application/json"),a.send(JSON.stringify(e))}}}(l,p))}function i(e,t){f||setTimeout(function(){!t&&m.core||a()},500)}var e=function(){var n=l.createElement(k);n.src=h;var e=y[w];return!e&&""!==e||"undefined"==n[w]||(n[w]=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(k)[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[I]&&!0!==s[I]){var c="onerror";t(["_"+c]);var u=T[c];T[c]=function(e,t,n,a,i){var r=u&&u(e,t,n,a,i);return!0!==r&&m["_"+c]({message:e,url:t,lineNumber:n,columnNumber:a,error:i}),r},d.autoExceptionInstrumented=!0}return m}(y.cfg);function a(){y.onInit&&y.onInit(n)}(T[t]=n).queue&&0===n.queue.length?(n.queue.push(a),n.trackPageView({})):a()}(window,document,{
    src: "https://js.monitor.azure.com/scripts/b/ai.2.min.js", // The SDK URL Source
    // name: "appInsights", // Global SDK Instance name defaults to "appInsights" when not supplied
    ld: -1, // 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
    // onInit: null, // Once the application insights instance has loaded and initialized this callback function will be called with 1 argument -- the sdk instance (DO NOT ADD anything to the sdk.queue -- As they won't get called)
    cfg: { // Application Insights Configuration
        instrumentationKey: "REDACTED"
    }});
    </script>
    <link href="css/bootstrap/bootstrap.min.css" rel="stylesheet" />
    <link href="css/app.css" rel="stylesheet" />
    <link href="AITest.Client.styles.css" rel="stylesheet" />
    <link href="_content/BlazorMonaco/lib/monaco-editor/min/vs/editor/editor.main.css" rel="stylesheet" />
</head>

<body>
    <div id="app">Loading...</div>

    <div id="blazor-error-ui">
        An unhandled error has occurred.
        <a href="" class="reload">Reload</a>
        <a class="dismiss">🗙</a>
    </div>

    <script src="_content/BlazorMonaco/lib/monaco-editor/min/vs/loader.js"></script>
    <script>require.config({ paths: { 'vs': '_content/BlazorMonaco/lib/monaco-editor/min/vs' } });</script>
    <script src="_content/BlazorMonaco/lib/monaco-editor/min/vs/editor/editor.main.js"></script>
    <script src="_content/BlazorMonaco/jsInterop.js"></script>

    <script src="_framework/blazor.webassembly.js"></script>
</body>

</html>

Issue Analytics

State:
Created 2 years ago
Comments:14 (13 by maintainers)

Top GitHub Comments

1reaction

MSNevcommented, Jan 14, 2022

Thanks for the clarification. Should I also report this to Edge for them to investigate?

It wouldn’t hurt, but I’ll also try and carve out some time to investigate further as this is unexpected. I also need to go back and re-read the spec about this as I vaguely remember something about using document.write() which we can’t do anymore because we are listening to whether the script can be loaded successfully.

0reactions

MSNevcommented, Nov 11, 2022

Based on what I investigated and reported in Jan, the -1 is working as expected by blocking the “onload” to be delayed. For the case of modern browsers still loading and executing other scripts before the SDK is loaded, I don’t believe that there is any way for the SDK to cause the browser to block the execution of those other scripts… As such I don’t have any work items scheduled or otherwise to try to “fix” this…

So this means that because of the requirejs / define implementation the solution is to change the src script to the “gbl” version https://js.monitor.azure.com/scripts/b/ai.2.gbl.min.js which just executes the SDK as soon as it’s loaded (ie. it doesn’t have the prefix support for working with requireJs and define)