Python Module to Read EPICS Database

Simply put, this module implements iocsh commands dbLoadRecords and dbLoadTemplate in Python. Each record is represented by a Record object and then records are aggregated into a Database object.

Usage

from dbtoolspy import load_template_file, load_database_file
templates = load_template_file('example.subs')

templates is a list of (dbfile, macros) tuples. dbfile is the database file name and macros is a dictionary containing the macro substitution. They are then passed to load_database_file.

for dbfile, macros in templates:
    database = load_database_file(dbfile, macros)
    print(database)

database is a Database instance. Since Database derives from OrderedDict, it can be iterated:

for record in database.values():
    print(record.name)

Reference

load_template_file takes the following argument:

subsfile

Substitution file.

encoding

(Optional) File encoding. (default utf-8)

load_database_file takes the following argument:

dbfile

Database file.

macros

(Optional) Dict of macro substitution. If None is given, no macro expansion is performed.

includes

(Optional) Extra include paths for database files.

encoding

(Optional) File encoding. (default utf-8)

Record has the following attibutes:

name

Record name.

rtyp

Record type.

fields

Dictionary of record fields.

infos

Dictionary of record infos.

aliases

List of aliased names.

Database derives from OrderedDict. The key is the record name and the value the Record instance. Additional methods:

add_record

Add a new Record instance.

update

Add records from another Database instance. If there exists a record with the same name and the same rtyp, the new fields, infos and aliases attributes will merge with the existing. If rtyp is difference, DatabaseException will be raised.

Tools

dbiocdiff.py

It compares the configured field values with the IOC runtime values and reports the difference.

Limitations

• In the substitution file, the template file name cannot contain macros.
• It is stricter when treating valid characters in bare words. Quote them in case of TokenException.