Custom Traces

Introduction

The Memfault SDK has the ability to capture Custom Traces, which are user-defined events recorded for critical errors that do not dump a core file to the Linux core handler.

Custom traces can be generated in several ways when working with the local memfaultd daemon:

Using memfaultctl CLI

The memfaultctl command-line tool provides a convenient way to save custom traces:

memfaultctl save-trace --program <program> --reason <reason> [--crash <crash>] [--source <source>] [--signature <signature>]

Options:

• --program: name of program reporting the Trace (Required)
• --reason: reason for Trace collection (Required)
• --crash: whether or not the Trace represents a crash (Optional, default value: True)
• --source: the source of the Trace (largely used for internal reporting) (Optional, default value: Unknown)
• --signature: input for Memfault signature algorithm that determines which Traces are grouped together (Optional, default value: None)

Using HTTP API

You can also generate custom traces by making HTTP requests directly to the memfaultd daemon:

curl --header "Content-Type: application/json" \
     --request POST \
     --data '{
       "signature": "SIGNATURE",
       "crash": true,
       "reason": "UpdateError",
       "program": "ota.py"
     }' \
     http://127.0.0.1:8787/v1/trace/save -v

Both methods allow you to capture relevant events and provide the necessary context for effective debugging and monitoring.