@sc-voice/state-log

Javascript client and server library for differntial logging. Usefulfor monitoring remote server state that changes infrequently. Compatible with any HTTP server that provide status information in JSON format.

Compact logging

Information is logged compactly and grows incrementally only if the state actually changes-- if a monitored state doesn't change for years, the log won't grow. Full state log can be sent over HTTP to support arbitrary client views.

State normalization

Select fields can be chosen from raw JSON to create a normalized state for logging. Normalization can also be applied to JSON property value strings using regular expressions that match the value substring to retain. Normalization is required to remove any timestamps embedded in the state to be logged. Timestamps defeat the purpose of differential logging.

Client and Server

The Javacript library can be used in NodeJS as well as in a browser.

Serialization

Logs are serializable as JSON files.

See API

Command line utilities

test-util

Monitor given URL periodically, sending any new state to stdout. Default URL is

• http://worldtimeapi.org/api/timezone/America/Los_Angeles

Users can specify a JSON filter that chooses desired properties or matches key portions of timestamps. Here, we extract the HH:MM:S part of a given timestamp using StateLog normalization:

scripts/test-url --json-filter '{datetime:"T[^:]+:[^:]+:."}'