mflt-compact-log 0.0.1

Memfault Compact Log Library

Memfault Compact Log Library

This library enables decoding Memfault-flavored compact logs. For background information on compact logs, see here:

https://mflt.io/compact-logs

Usage

Some brief usage information below. See the source for detailed usage.

Extracting compact log format strings from .elf

To extract the format strings from the symbol file:

from mflt_compact_log.log_fmt import LogFormatElfSectionParser

elf = "path to elf file"
# parse the elf file
mappings = LogFormatElfSectionParser.get_mapping_from_elf_file(elf)
# 'mappings' is a dictionary mapping log id to LogFormatInfo data
print(mappings)

>>> {8: LogFormatInfo(filename='./main/console_example_main.c', line=245, n_args=0, fmt='This is a compact log example')}

Decoding compact logs

To apply the format string to raw compact log data:

from mflt_compact_log.compact import CompactLogDecoder

# example format string; this could instead be retrieved from the elf file
fmt = "An Integer Format String: %d"

# compact log hex encoded raw data
compact_log = "820A0B"

# decode the log!
compact_log_as_bytes = bytes.fromhex(compact_log)
log = CompactLogDecoder.from_cbor_array(fmt, compact_log_as_bytes)
log.decode()
>>> 'An Integer Format String: 11'