Captured logs: log lines truncated at maximum length — split long messages in app code or use external logging service

Android

When you use Esper's Capture Logs feature to retrieve logcat output from your managed devices, you may notice that log lines are cut off after a certain character length. This article explains why this happens and shows you how to resolve it.

Why log lines are truncated

Android's logcat system enforces a maximum length per log entry at the operating system level. The Esper Capture Logs feature reads directly from your device's logcat buffer and cannot override this platform-level constraint. Any single log call that exceeds approximately 4,000 characters will be silently truncated by Android before Esper ever reads it.

Before you begin

Identify which parts of your application are writing excessively long log messages. Review your app's logging code for any single Log.d(), Log.e(), Log.i(), Log.v(), or Log.w() calls that pass a string exceeding approximately 4,000 characters.

Solution 1: Split long log messages in your app code

Divide large payloads across multiple sequential log calls instead of logging them as a single entry. Each chunk will appear as a separate line in your captured logs.

Replace a single long log call with a loop that chunks the message into smaller pieces:

// Instead of:
// Log.d(TAG, veryLongString);

// Use this approach:
int chunkSize = 3000;
for (int i = 0; i < veryLongString.length(); i += chunkSize) {
 Log.d(TAG, veryLongString.substring(i, Math.min(i + chunkSize, veryLongString.length())));
}

After you update your app code, re-run Capture Logs from Devices & Groups → [Device Name] → Capture Logs and verify that all expected content appears across multiple sequential lines with no mid-line truncation.

Solution 2: Use an external logging service for high-volume data

If your application generates large payloads, structured logs, or verbose diagnostic data, route that information to a dedicated logging service instead of relying on Android logcat. Examples include:

Datadog
Splunk
Timber
Firebase Crashlytics

The Esper Capture Logs feature is best suited for standard-length diagnostic output, not bulk data transport.

Solution 3: Adjust logcat buffer size (temporary, per-device)

On devices where Developer Options are accessible, you can increase the total logcat buffer capacity. Note that this does not increase the per-line character limit — it only increases total buffer size. Use this approach only if you suspect buffer overflow across many log lines:

In the Esper Console, navigate to Devices & Groups → [Device Name] → Remote Control
Use Remote Control to open Settings → Developer Options → Logger buffer sizes
Increase the buffer size per log type (default is typically 256 KB; maximum is 16 MB)

Keep in mind that changes made via Developer Options are not persisted if the device is factory reset or if a Blueprint re-apply enforces Developer Options settings.

Troubleshooting

If lines are still truncated after you split them at 3,000 characters or less:

Test with shorter chunks (for example, 1,000 characters) to identify your device's exact character limit — this may vary by device manufacturer and firmware version.
If truncation occurs at an unusually short length (for example, under 500 characters), collect a bug report from Devices & Groups → [Device Name] → Bug Report and contact Esper Support with your device model, Android OS version, and Esper Agent version.

Still need help?

If you've tried these solutions and are still experiencing truncated log lines, contact Esper Support. include your device model, Android version, Esper Agent version, and a bug report collected from the Esper Console.