Logging and log analysis in Drone Programming - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Drone log filtering command output

You have a drone log file named flight.log containing thousands of lines. You want to extract only the lines that contain the word ERROR. Which command will correctly output these lines?

A grep ERROR flight.log

B cat flight.log | find ERROR

C grep 'error' flight.log

D findstr ERROR flight.log

💡 Hint

Think about the standard Linux command to search text in files, case-sensitive by default.

The grep ERROR flight.log command searches for the exact uppercase word ERROR in the file and outputs matching lines. Option A uses find which is not standard on Linux. Option A searches for lowercase 'error' which won't match uppercase ERROR. Option A is a Windows command.

🧠 Conceptual

intermediate

Purpose of log rotation in drone systems

Why is log rotation important in drone software systems that generate continuous logs?

A To combine all logs into one big file for easier reading

B To delete all logs after every flight automatically

C To prevent log files from growing too large and consuming all disk space

D To encrypt logs for security purposes

💡 Hint

Think about disk space and file management.

Log rotation splits large log files into smaller chunks and deletes or archives old logs. This prevents disk space from filling up and keeps logs manageable. Options B, C, and D do not describe log rotation.

❓ Troubleshoot

advanced

Troubleshooting missing logs in drone system

A drone system is not generating any logs in the expected directory /var/log/drone. Which of the following is the most likely cause?

A The log files are encrypted and hidden

B The logging service is not started or crashed

C The drone is flying too fast to generate logs

D The drone battery is low

💡 Hint

Think about the software responsible for writing logs.

If no logs appear, the logging service or daemon might not be running or has crashed. Flying speed or battery level does not affect log generation directly. Encryption hides logs but does not prevent their creation.

🔀 Workflow

advanced

Analyzing drone logs for flight anomalies

You want to analyze drone flight logs to find all instances where the altitude dropped suddenly by more than 10 meters within 1 second. Which workflow sequence is correct?

A 1,3,2,4

B 3,1,2,4

C 2,1,3,4

D 1,2,3,4

💡 Hint

Think about the logical order of data extraction, calculation, filtering, and reporting.

First extract data (1), then calculate differences (2), filter relevant drops (3), and finally report (4). Other orders skip necessary steps or filter before calculation.

✅ Best Practice

expert

Best practice for secure drone log storage

Which option is the best practice to securely store drone logs containing sensitive flight data?

A Store logs on an encrypted remote server with access control

B Keep logs only on the drone's local storage without backup

C Send logs via unencrypted email to the operator

D Print logs on paper after each flight

💡 Hint

Consider data security and accessibility.

Storing logs on an encrypted remote server with strict access control protects sensitive data from unauthorized access and loss. Local-only storage risks data loss. Unencrypted email and printing are insecure or impractical.