bifrost-common-py 0.8

Common python library functions for interacting with BIFROST.

bifrost-common

A library of commonly used functions to interact with BIFROST. Useful for module developers.

Installation

pip install bifrost-common-py

Components

Log

A module to print nice logging information to the console and, optionally, to files.

from bifrost_common_py.Log import Log

log = Log('myComponent', 'myApplication', options={'maxLogFileSize':1e4, 'enableLogFiles':True})

log.write(`Abandon ship`, Log.WARNING)
log.write(`Run like hell`, Log.INFO)

Log levels are DEBUG, INFO, WARNING, ERROR, FAILURE

Allowed options are:

• enableLogFiles (default: false): log to files as well as the console
• logDir (default: log): the log file directory (will be created as necessary)
• maxLogFileSize (default: 0): maximum byte size of the log files, after which a new file will be started, default =0 never rollover
• maxArchiveSize(default: 5): maximum number of log files to keep

time

Some useful operations involving time, mostly for formatting Log output.

idOfRef

Resolve the ID contained in an object. If no 'id' field is found in the object pointed to with ref, the last part of the reference is returned instead.

from bifrost_common_py.idOfRef import idOfRef

print(idOfRef({ 'A': { 'id': '1' }}, '/A')) // '1'

tokens

An object collecting string tokens commonly used in the BIFROST state.

import bifrost_common_py.tokens as tokens

print(tokens.tkId) // "id"

select

Selectors returning fully-qualified JSON paths into the BIFROST state.

import bifrost_common_py.pathSelectors as select

print(select.meta())                      # "/meta"
print(select.dynamicId('DYNAMIC-1'))      # "/dynamics/byId/DYNAMIC-1"
print(select.eventParentRef('EVENT-1'))   # "/events/byId/EVENT-1/parentRef"

safepointer

A wrapper that allows to specify default values if paths can not be resolved. This is best used in conjunction with select and a copy of the BIFROST state.

API

import bifrost_common_py.safepointer

.has(obj, path)

Determine whether the fully-qualified JSON pointer path points to something in obj.

safepointer.has({ 'A': { 'B': 1} }, '/A/B') # true
safepointer.has({ 'A': { 'B': 1} }, '/A/C') # false

.get(obj, path, def = null)

Resolve path against obj. If the path does not exist, def is returned instead.

safepointer.get({ 'A': { 'B': 1} }, '/A/B', 0)  # 1
safepointer.get({ 'A': { 'B': 1} }, '/A/C', 0)  # 0

import bifrost_common_py.pathSelectors as select

safepointer.get(state, select.meta(), {}) // { id: ... }

SelectFrom

A declarative state selection library. Use this to select elements from the BIFROST state or from module subscription data.

    from bifrost_common_py.SelectFrom import SelectFrom

    SelectFrom(state).allDynamics().ofType('VOLTAGE-3P').asValueMap()

    SelectFrom(subs).allEntries().ofType('CLIMATE-MODEL').asValueList()

    SelectFrom(subs, state).allEntries().withParentOfType('WEATHER').asValueMap()