How to query Azure App Insights logs using Node.JS - node.js

Question

There is an example how it is possible to query
LogAnalytics Workspace Logs or
Metrics for individual resources
using Node.Js:
But I could not find if there is an option to query Logs from AppInsights or from resource directly.
I need it to automate reporting of the performance, so I am planning to query requests table (we send logs using https://github.com/microsoft/ApplicationInsights-Java). Currently report is done manually using Performance blade of the AppInsights - checking Avg and 99 percentile for requests with specific filters on URL

Answer 1

You can setup logs ingestion from your application to Log Analytics Workspace using Diagnostic Settings. For example, if you host your app in WebApp you can send AppServiceHTTPLogs. And then in your Node.JS app you can use #azure/monitor-query package with a similar query:
let dataset=AppServiceHTTPLogs
| where CsHost == 'PUT_YOUR_HOSTNAME_HERE'
| where ScStatus == 200
| where CsUriStem contains 'FILTER_BY_URL_IF_YOU_NEED_IT';
dataset
| summarize arg_max(TimeTaken, CsUriStem)
| union(dataset
| summarize avg(TimeTaken), percentiles(TimeTaken, 99)
| extend CsUriStem='Overall')
That one is a close approximation of the performance blade from app insights.
And then your whole app could be
const azureLogAnalyticsWorkspaceId = "WORKSPACE_ID";
const logsQueryClient = new LogsQueryClient(new DefaultAzureCredential());
export async function runWebAppPerformance(startDate: Date, endDate: Date) {
const query = "PUT_YOUR_QUERY_HERE";
const result = await logsQueryClient.queryWorkspace(
azureLogAnalyticsWorkspaceId,
query,
{
startTime: startDate, endTime: endDate
}
);
if (result.status === LogsQueryResultStatus.Success) {
const tablesFromResult: LogsTable[] = result.tables;
if (tablesFromResult.length === 0) {
console.log(`No results for query`);
return;
}
processTables(tablesFromResult);
} else {
console.log(`Error processing the query - ${result.partialError}`);
}
}
async function processTables(tablesFromResult: LogsTable[]) {
const table = tablesFromResult[0];
const urlIndex = table.columnDescriptors.findIndex(c => c.name === "CsUriStem");
const timeTakenIndex = table.columnDescriptors.findIndex(c => c.name === "TimeTaken");
const avgIndex = table.columnDescriptors.findIndex(c => c.name === "avg_TimeTaken");
const ninetyNineindex = table.columnDescriptors.findIndex(c => c.name === "percentile_TimeTaken_99");
for (const row of table.rows) {
if (row[urlIndex] === "Overall"){
console.log(`${row[urlIndex]} (ms):`);
console.log(`Average: ${row[avgIndex]}; \t 99%: ${row[ninetyNineindex]}`);
}
else {
console.log(`MAX (ms)`);
console.log(`${row[urlIndex]}: \t ${row[timeTakenIndex]}`);
}
}
}

Answer 2

How to query Azure App Insights logs using Node.JS
In Azure Portal, Create Application Insights Instance and Copy the Instrumentation key from the overview page
Create a sample NodeJS Web App in Visual Studio code
We can add the instrumentation key in localhost or can be updated once after nodejs application is deployed to Azure.Here I have added the required application insight setting and deployed the App
In server.js, add
let appInsights = require('applicationinsights');
appInsights.setup("cc580d32-a7eb-41d7-b0e0-90ea0889fd10");
appInsights.start();
From the root folder of the Application, open the terminal and run
npm install applicationinsights --save
Deploy the Application to Azure
Browse the Application
View Logs in Application Insights
Application Insights queries are based on KQL
Navigate to Azure Portal => Your Application Insights Instance => Logs under Monitoring = > Click on traces
Metrics for individual resources using Node.Js
Navigate to metrics under Monitoring
Please refer Node.js services with Application Insights for more information