export function setupAndStart()

in Bootstrap/Default.ts [50:134]
54 lines of code
9 McCabe index (conditional complexity)

export function setupAndStart(setupString = _setupString, aadTokenCredential?: azureCore.TokenCredential): typeof types | null {
    // If app already contains SDK, skip agent attach
    if (!forceStart && Helpers.sdkAlreadyExists(_logger)) {
        _statusLogger.logStatus({
            ...defaultStatus,
            AgentInitializedSuccessfully: false,
            SDKPresent: true,
            Reason: "SDK already exists"
        })
        return null;
    }

    if (!setupString) {
        const message = "Application Insights wanted to be started, but no Connection String or Instrumentation Key was provided";
        _logger.logError(message);
        _statusLogger.logStatus({
            ...defaultStatus,
            AgentInitializedSuccessfully: false,
            Reason: message,
        });
        return null;
    }

    try {
        _appInsights = require("../applicationinsights");
        if (_appInsights.defaultClient) {
            // setupAndStart was already called, return the result
            _logger.logError("Setup was attempted on the Application Insights Client multiple times. Aborting and returning the first client instance");
            return _appInsights;
        }

        const prefixInternalSdkVersion = function (envelope: types.Contracts.Envelope, _contextObjects: Object) {
            try {
                var appInsightsSDKVersion = _appInsights.defaultClient.context.keys.internalSdkVersion;
                envelope.tags[appInsightsSDKVersion] = _prefix + envelope.tags[appInsightsSDKVersion];
            } catch (e) {
                _logger.logError("Error prefixing SDK version", e);
            }
            return true;
        }

        const copyOverPrefixInternalSdkVersionToHeartBeatMetric = function (envelope: types.Contracts.Envelope, _contextObjects: Object) {
            var appInsightsSDKVersion = _appInsights.defaultClient.context.keys.internalSdkVersion;
            const sdkVersion = envelope.tags[appInsightsSDKVersion] || "";
            if (envelope.name === Constants.HeartBeatMetricName) {
                ((envelope.data as any).baseData).properties = ((envelope.data as any).baseData).properties || {};
                ((envelope.data as any).baseData).properties["sdk"] = sdkVersion;
            }

            return true;
        }

        // Instrument the SDK
        _appInsights.setup(setupString).setSendLiveMetrics(true);
        _appInsights.defaultClient.setAutoPopulateAzureProperties(true);
        _appInsights.defaultClient.addTelemetryProcessor(prefixInternalSdkVersion);
        _appInsights.defaultClient.addTelemetryProcessor(copyOverPrefixInternalSdkVersionToHeartBeatMetric);
        if (aadTokenCredential) {
            _logger.logMessage("Using AAD Token Credential");
            _appInsights.defaultClient.config.aadTokenCredential = aadTokenCredential;
        }
        
        _appInsights.start();
        // Add attach flag in Statsbeat
        let statsbeat = _appInsights.defaultClient.getStatsbeat();
        if (statsbeat) {
            statsbeat.setCodelessAttach();
        }

        // Agent successfully instrumented the SDK
        _logger.logMessage("Application Insights was started with setupString: " + setupString);
        _statusLogger.logStatus({
            ...defaultStatus,
            AgentInitializedSuccessfully: true
        });
    } catch (e) {
        _logger.logError("Error setting up Application Insights", e);
        _statusLogger.logStatus({
            ...defaultStatus,
            AgentInitializedSuccessfully: false,
            Reason: `Error setting up Application Insights: ${e && e.message}`
        })
    }
    return _appInsights;
}