https://github.com/diamondlightsource/aapy

Python API for fetching data from the EPICS Archiver Appliance
https://github.com/diamondlightsource/aapy

from-dls-controls

Last synced: 11 months ago
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Python API for fetching data from the EPICS Archiver Appliance

• Host: GitHub
• URL: https://github.com/diamondlightsource/aapy
• Owner: DiamondLightSource
• License: apache-2.0
• Created: 2017-08-16T13:22:15.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2024-07-15T11:19:06.000Z (over 1 year ago)
• Last Synced: 2025-01-15T01:50:39.854Z (about 1 year ago)
• Topics: from-dls-controls
• Language: Python
• Size: 10.2 MB
• Stars: 2
• Watchers: 6
• Forks: 3
• Open Issues: 7
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
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Python code to retrieve data from the

[EPICS Archiver Appliance](https://slacmshankar.github.io/epicsarchiver_docs/).

## Usage

### Note on timezones

When you pass a datetime to aapy it doesn't know by default what timezone

that datetime is supposed to be in. It will assume that it is the local

timezone, but will print a warning. If you pass it a timezone-aware

datetime no warning will be printed. You can use `utc_datetime()` as

a shortcut:

    >>> from aa.utils import utc_datetime

    >>> utc_datetime(2019, 10, 7, 17) # 5pm UTC on 7th October 2019

### Fetching data

To retrieve data, create the appropriate fetcher

    >>> from aa.js import JsonFetcher

    >>> jf = JsonFetcher('archappl.diamond.ac.uk', 80)

You can request a single event, returning an ArchiveEvent object:

    >>> from datetime import datetime

    >>> event = jf.get_event_at('SR-DI-DCCT-01:SIGNAL', datetime.now())

    WARNING:root:Assuming timezone for 2019-10-07 16:42:13.301672 is Europe/London

    Archive event for PV SR-DI-DCCT-01:SIGNAL: timestamp 2019-10-07

    15:42:04.876639 UTC value [301.33007915] severity 0

    >>> event.value

    array([300.77982715])

    >>> event.utc_datetime

    datetime.datetime(2019, 10, 7, 16, 2, 54, 928836, tzinfo=)

You can also request a range of events, returning an ArchiveData object:

    >>> data = jf.get_values('SR-DI-DCCT-01:SIGNAL', utc_datetime(2018, 1, 7), utc_datetime(2018, 1, 8))

    >>> data.values

    array([[2.51189843e-03],

       [1.56371643e-03],

       [5.54392030e-04],

       ...,

       [2.77373366e+02],

       [2.77329542e+02],

       [2.77287664e+02]])

    >>> data.utc_datetimes

    array([datetime.datetime(2018, 1, 6, 23, 59, 59, 3897, tzinfo=),

       datetime.datetime(2018, 1, 7, 0, 0, 2, 3975, tzinfo=),

       datetime.datetime(2018, 1, 7, 0, 0, 5, 4066, tzinfo=), ...,

       datetime.datetime(2018, 1, 7, 23, 59, 53, 3885, tzinfo=),

       datetime.datetime(2018, 1, 7, 23, 59, 56, 3825, tzinfo=),

       datetime.datetime(2018, 1, 7, 23, 59, 59, 3726, tzinfo=)],

      dtype=object)

    >>> len(data)

    28764

## Development

aapy uses Pipenv to manage its dependencies.

To install development requirements:

    pipenv install --dev

To run the tests and static checks:

    pipenv run tests