Server API

Data Containers

Core

The following are the underlying, lowest-level classes for holding data which can be sent over an EPICS V3 channel in caproto.

Numeric Data

caproto.ChannelData(*[, alarm, value, ...])	Base class holding data and metadata which can be sent across a Channel.
caproto.ChannelDouble(*[, precision])	64-bit floating point data and metadata which can be sent over a channel.
caproto.ChannelFloat(*[, precision])	32-bit floating point data and metadata which can be sent over a channel.
caproto.ChannelInteger(*, value[, units, ...])	32-bit LONG integer data and metadata which can be sent over a channel.
caproto.ChannelShort(*, value[, units, ...])	16-bit SHORT integer data and metadata which can be sent over a channel.

String or Byte Data

caproto.ChannelByte(*[, string_encoding, ...])	8-bit unencoded CHAR data plus metadata which can be sent over a channel.
caproto.ChannelChar(*[, alarm, value, ...])	8-bit encoded CHAR data plus metadata which can be sent over a channel.
caproto.ChannelEnum(*[, enum_strings])	ENUM data which can be sent over a channel.
caproto.ChannelString(*[, alarm, value, ...])	8-bit encoded string data plus metadata which can be sent over a channel.

Base Class

The above share methods from their common (internal) base class ChannelData.

ChannelData(*[, alarm, value, timestamp, ...])

Base class holding data and metadata which can be sent across a Channel.

PvpropertyData

pvproperty builds on top of ChannelData with the following classes, separated by whether or not they are read-only.

caproto.server.PvpropertyData(*, pvname, ...)

A top-level class for mixing in with ChannelData subclasses.

Read/write

caproto.server.PvpropertyBoolEnum(*[, ...])	Read-write ENUM data for pvproperty, with Off/On as default strings.
caproto.server.PvpropertyByte(*, pvname, ...)	Read-write 8-bit CHAR data for pvproperty for bytes.
caproto.server.PvpropertyChar(*, pvname, ...)	Read-write 8-bit CHAR data for pvproperty with string encoding.
caproto.server.PvpropertyDouble(*, pvname, ...)	Read-write DOUBLE data for pvproperty (64 bits).
caproto.server.PvpropertyEnum(*[, ...])	Read-write ENUM data for pvproperty.
caproto.server.PvpropertyFloat(*, pvname, ...)	Read-write FLOAT data for pvproperty (32 bits).
caproto.server.PvpropertyInteger(*, pvname, ...)	Read-write LONG data for pvproperty (32 bits).
caproto.server.PvpropertyReadOnlyData(*, ...)	A mixin class which marks this data as read-only from channel access.
caproto.server.PvpropertyShort(*, pvname, ...)	Read-write SHORT/INT data for pvproperty (16 bits).
caproto.server.PvpropertyString(*, pvname, ...)	Read-write STRING data for pvproperty (up to 40 chars).

Read-only

Read-only data classes mix in with PvpropertyReadOnlyData.

caproto.server.PvpropertyBoolEnumRO(*[, ...])	Read-only ENUM data for pvproperty, with Off/On as default strings.
caproto.server.PvpropertyByteRO(*, pvname, ...)	Read-only 8-bit CHAR data for pvproperty for bytes.
caproto.server.PvpropertyCharRO(*, pvname, ...)	Read-only 8-bit CHAR data for pvproperty with string encoding.
caproto.server.PvpropertyDoubleRO(*, pvname, ...)	Read-only DOUBLE data for pvproperty (64 bits).
caproto.server.PvpropertyEnumRO(*[, ...])	Read-only ENUM data for pvproperty.
caproto.server.PvpropertyFloatRO(*, pvname, ...)	Read-only FLOAT data for pvproperty (32 bits).
caproto.server.PvpropertyIntegerRO(*, ...[, ...])	Read-only LONG data for pvproperty (32 bits).
caproto.server.PvpropertyShortRO(*, pvname, ...)	Read-only SHORT/INT data for pvproperty (16 bits).
caproto.server.PvpropertyStringRO(*, pvname, ...)	Read-only STRING data for pvproperty (up to 40 chars).

High-level API / pvproperty magic

caproto.server.PVSpec([get, put, startup, ...])	Create new instance of PVSpec(get, put, startup, shutdown, attr, name, dtype, value, max_length, alarm_group, read_only, doc, fields, scan, record, cls_kwargs)
caproto.server.expand_macros(pv, macros)	Expand a PV name with Python {format-style} macros

caproto.server.PVGroup(prefix, *[, macros, ...])	Class which groups a set of PVs for a high-level caproto server
caproto.server.pvproperty([get, put, ...])	A property-like descriptor for specifying a PV in a PVGroup.
caproto.server.PvpropertyData(*, pvname, ...)	A top-level class for mixing in with ChannelData subclasses.
caproto.server.SubGroup([group, prefix, ...])	A property-like descriptor for specifying a subgroup in a PVGroup.
caproto.server.pvfunction([func, default, ...])	A descriptor for making an RPC-like function.
caproto.server.expand_macros(pv, macros)	Expand a PV name with Python {format-style} macros
caproto.server.get_pv_pair_wrapper([...])	Generates a Subgroup class for a pair of PVs (setpoint and readback).
caproto.server.scan_wrapper(scan_function, ...)	Wrap a function intended for pvproperty.scan with common logic to periodically call it.

Command-line Helpers

Tools for helping to generate command-line argument parsers for use with IOCs.

caproto.server.template_arg_parser(*, desc, ...)	Construct a template arg parser for starting up an IOC
caproto.server.ioc_arg_parser(*, desc, ...)	A reusable ArgumentParser for basic example IOCs.
caproto.server.run(pvdb, *[, module_name, ...])	Run an IOC, given its PV database dictionary and async-library module name.

Advanced / Internal

The following are related to the internal mechanisms that PVGroup and pvproperty rely on.

caproto.server.server.FieldProxy(field_spec, ...)	A proxy class which allows access to pvproperty.fields.Field.
caproto.server.server.FieldSpec(prop, *, ...)	A field specification for a pvproperty record.
caproto.server.server.NestedPvproperty([...])	Nested pvproperty which allows decorator usage in parent class
caproto.server.server.PVGroupMeta(name, ...)	Metaclass that finds all pvproperties

Library-agnostic server core

Core Classes

These are mostly as-is by all server implementations.

caproto.server.AsyncLibraryLayer()	Library compatibility layer.
caproto.server.common.Subscription(mask, ...)	Create new instance of Subscription(mask, channel_filter, circuit, channel, data_type, data_count, subscriptionid, db_entry)
caproto.server.common.SubscriptionSpec(...)	Create new instance of SubscriptionSpec(db_entry, data_type_name, mask, channel_filter)

Base Classes

These are intended to be subclassed to implement support for a new async library.

caproto.server.common.Context(pvdb[, interfaces])
caproto.server.common.VirtualCircuit(...)

Exceptions

caproto.server.common.DisconnectedCircuit
caproto.server.common.LoopExit

asyncio server

Implementation classes

Classes built on top of the library-agnostic core, used to implement asyncio functionality.

caproto.asyncio.server.AsyncioAsyncLayer()
caproto.asyncio.server.Context(pvdb[, ...])
caproto.asyncio.server.Event	alias of AsyncioEvent
caproto.asyncio.server.ServerExit
caproto.asyncio.server.VirtualCircuit(...[, ...])	Wraps a caproto.VirtualCircuit with an asyncio client.

Helper functions

caproto.asyncio.server.run(pvdb, *[, ...])	Run an IOC, given its PV database dictionary.
caproto.asyncio.server.start_server(pvdb, *)	Start an asyncio server with a given PV database

Curio server

Implementation classes

Classes built on top of the library-agnostic core, used to implement asyncio functionality.

caproto.curio.server.CurioAsyncLayer()
caproto.curio.server.Context(pvdb[, interfaces])
caproto.curio.server.Event()
caproto.curio.server.ServerExit
caproto.curio.server.VirtualCircuit(circuit, ...)	Wraps a caproto.VirtualCircuit with a curio client.

Helper functions

caproto.curio.server.run(pvdb, *[, ...])	Run an IOC, given its PV database dictionary.
caproto.curio.server.start_server(pvdb, *[, ...])	Start a curio server with a given PV database

Miscellaneous

caproto.curio.server.QueueWithFullError([...])
caproto.curio.server.QueueFull
caproto.curio.server.UniversalQueue(*[, ...])

Trio server

Implementation classes

Classes built on top of the library-agnostic core, used to implement asyncio functionality.

caproto.trio.server.TrioAsyncLayer()
caproto.trio.server.Context(pvdb[, interfaces])
caproto.trio.server.Event()	The class wraps trio.Event and implements Event.clear() method that is used in the code, but deprecated in trio.
caproto.trio.server.ServerExit
caproto.trio.server.VirtualCircuit(circuit, ...)	Wraps a caproto.VirtualCircuit with a trio client.

Helper functions

caproto.trio.server.run(pvdb, *[, ...])	Run an IOC, given its PV database dictionary.
caproto.trio.server.start_server(pvdb, *[, ...])	Start a trio server with a given PV database