Log dictionaries to file using the MessagePack serialization format.
Project description
mpacklog.py
Stream dictionaries to files or over the network using MessagePack in Python.
Installation
From conda-forge
conda install -c conda-forge mpacklog
From PyPI
pip install mpacklog
Usage
Asynchronous API
Add messages to the log using the put
function, have them written to file in the separate write
coroutine.
import asyncio
import mpacklog
async def main():
logger = mpacklog.AsyncLogger("output.mpack")
await asyncio.gather(main_loop(logger), logger.write())
async def main_loop(logger):
for bar in range(1000):
await asyncio.sleep(1e-3)
await logger.put({"foo": bar, "something": "else"})
await logger.stop()
if __name__ == "__main__":
asyncio.run(main())
Synchronous API
The synchronous API is similar to the asynchronous API, except it doesn't provide a stop
method and the put
and write
methods are blocking.
import mpacklog
logger = mpacklog.SyncLogger("output.mpack")
for bar in range(1000):
logger.put({"foo": bar, "something": "else"})
# Flush all messages to the file
logger.write()
Command-line
The mpacklog
utility provides commands to manipulate .mpack
files.
dump
The dump
command writes down a log file to newline-delimited JSON:
mpacklog dump my_log.mpack
list
This commands lists all nested dictionary keys encountered in a log file. Nested keys are separated by slashes /
in the output. For instance, if some dictionaries in my_log.mpack
contain values at dict["foo"]["bar"]
and dict["foo"]["cbs"]
, the command will produce:
$ mpacklog list my_log.mpack
- foo/bar
- foo/cbs
serve
The serve
command watches a log file for updates and serves the last dictionary appended to it over the network. Its argument is either a log file or a directory containing log files. In the second case, the most recent log files in the directory is opened:
$ mpacklog serve /var/log/my_mpack_logs/
You can use mpackview
to connect a live plot to the server, or develop your own tool (the server API is quite simple).
See also
- foxplot: explore and plot time-series data from MessagePack and line-delimited JSON files.
- jq: manipulate JSON series to add, remove or extend fields.
- mpacklog.cpp: log dictionaries to MessagePack files in C++.
- rq: transform from/to MessagePack, JSON, YAML, TOML, etc. For instance
mpacklog dump
is equivalent torq -mJ < my_log.mpack
.
Project details
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