Split baseline from polling

Author: kylebonnici

src/features/flows/nRF54L15_cloud/evaluate/TestCrash.tsx

@@ -12,7 +12,7 @@ import { useAppDispatch, useAppSelector } from '../../../../app/store';
 import { Back } from '../../../../common/Back';
 import Main from '../../../../common/Main';
 import { Next, Skip } from '../../../../common/Next';
-import { pollCrashReport } from './api';
+import { fetchCrashBaseline, pollForNewCrash } from './api';
 import {
     getCrashReport,
     getCrashReportBaselineDate,
@@ -41,25 +41,49 @@ export default ({ vComIndex }: { vComIndex: number }) => {
         }
 
         const controller = new AbortController();
-        pollCrashReport(serialNumber, controller.signal, {
-            baseline: crashReportBaselineDate,
-            onBaseline: b => dispatch(setCrashReportBaselineDate(b)),
-        })
-            .then(crash => dispatch(setCrashReport(crash)))
-            .catch(e => {
-                if ((e as Error).name === 'AbortError') {
-                    return;
-                }
-                reportEvaluateError('Test crash', e, 'poll-crash');
-                setError(describeError(e));
-            });
+
+        if (crashReportBaselineDate === undefined) {
+            // First establish the baseline: whatever crash exists now is old.
+            fetchCrashBaseline(serialNumber, controller.signal)
+                .then(b => dispatch(setCrashReportBaselineDate(b)))
+                .catch(e => {
+                    if ((e as Error).name === 'AbortError') {
+                        return;
+                    }
+                    reportEvaluateError('Test crash', e, 'fetch-baseline');
+                    setError(describeError(e));
+                });
+        } else {
+            pollForNewCrash(
+                serialNumber,
+                crashReportBaselineDate,
+                controller.signal,
+            )
+                .then(crash => dispatch(setCrashReport(crash)))
+                .catch(e => {
+                    if ((e as Error).name === 'AbortError') {
+                        return;
+                    }
+                    reportEvaluateError('Test crash', e, 'poll-crash');
+                    setError(describeError(e));
+                });
+        }
 
         return () => controller.abort();
-        // When the first poll establishes the baseline, the effect is triggered again and restarts the poll once (with the established baseline).
+        // Once the baseline is established the effect re-runs and starts polling for a new crash.
     }, [dispatch, serialNumber, crashReport, error, crashReportBaselineDate]);
 
+    const preparingBaseline =
+        deviceInfo.status === 'success' &&
+        crashReportBaselineDate === undefined &&
+        !crashReport &&
+        !error;
+
     const waitingForCrash =
-        deviceInfo.status === 'success' && !crashReport && !error;
+        deviceInfo.status === 'success' &&
+        crashReportBaselineDate !== undefined &&
+        !crashReport &&
+        !error;
 
     return (
         <Main>
@@ -69,17 +93,20 @@ export default ({ vComIndex }: { vComIndex: number }) => {
                 fillHeight
             >
                 <div className="tw-flex tw-flex-col tw-gap-4">
-                    <div className="tw-flex tw-flex-col tw-gap-1">
-                        <span>
-                            Trigger a test crash by pressing <b>Button 1</b>.
-                        </span>
-                        <span>
-                            Your device will fault, reboot, and disconnect from
-                            the app. You need to reconnect the device to the
-                            app, which will send the crash report to the cloud
-                            over Bluetooth LE.
-                        </span>
-                    </div>
+                    {!preparingBaseline && (
+                        <div className="tw-flex tw-flex-col tw-gap-1">
+                            <span>
+                                Trigger a test crash by pressing <b>Button 1</b>
+                                .
+                            </span>
+                            <span>
+                                Your device will fault, reboot, and disconnect
+                                from the app. You need to reconnect the device
+                                to the app, which will send the crash report to
+                                the cloud over Bluetooth LE.
+                            </span>
+                        </div>
+                    )}
 
                     {deviceInfo.status === 'loading' && (
                         <div className="tw-flex tw-flex-row tw-items-center tw-gap-3">
@@ -90,6 +117,16 @@ export default ({ vComIndex }: { vComIndex: number }) => {
                         </div>
                     )}
 
+                    {preparingBaseline && (
+                        <div className="tw-flex tw-flex-row tw-items-center tw-gap-3">
+                            <Spinner size="sm" />
+                            <span className="tw-text-xs">
+                                Syncronizing with the cloud to prepare to fetch
+                                a crash report.
+                            </span>
+                        </div>
+                    )}
+
                     {waitingForCrash && (
                         <div className="tw-flex tw-flex-row tw-items-center tw-gap-3">
                             <Spinner size="sm" />

src/features/flows/nRF54L15_cloud/evaluate/api.ts

@@ -74,11 +74,6 @@ interface FinalizeSymbolBody {
     };
 }
 
-interface PollBaseline {
-    baseline: string | null | undefined;
-    onBaseline: (capturedDate: string | null) => void;
-}
-
 const bearer = (token: string) => ({ Authorization: `Bearer ${token}` });
 
 const mapCrash = ({
@@ -163,29 +158,33 @@ const fetchCrashReport = async (
     }
 };
 
-export const pollCrashReport = (
+// The crash that exists now (if any) is old; its date is the baseline for new crashes.
+export const fetchCrashBaseline = async (
     deviceSerial: string,
     signal: AbortSignal,
-    { baseline, onBaseline }: PollBaseline,
+): Promise<string | null> => {
+    const { status, crash } = await fetchCrashReport(deviceSerial, signal);
+    const isTerminal = status === 'processed' || status === 'symbolicated';
+    return isTerminal && crash ? crash.capturedDate : null;
+};
+
+export const pollForNewCrash = (
+    deviceSerial: string,
+    baseline: string | null,
+    signal: AbortSignal,
     intervalMs = POLL_INTERVAL_MS,
 ): Promise<CrashReport> => {
-    let current = baseline;
-
     const attempt = async (): Promise<CrashReport> => {
         if (signal.aborted) {
             throw new DOMException('Aborted', 'AbortError');
         }
         const { status, crash } = await fetchCrashReport(deviceSerial, signal);
         const isTerminal = status === 'processed' || status === 'symbolicated';
 
-        if (current === undefined) {
-            // The first request sets the baseline: the crash that exists now (if any) is old.
-            current = isTerminal && crash ? crash.capturedDate : null;
-            onBaseline(current);
-        } else if (isTerminal && crash) {
+        if (isTerminal && crash) {
             const isNew =
-                current === null ||
-                Date.parse(crash.capturedDate) > Date.parse(current);
+                baseline === null ||
+                Date.parse(crash.capturedDate) > Date.parse(baseline);
             if (isNew) {
                 return crash;
             }