Release History¶

v1.0.0 (2022-09-01)¶

Breaking Changes¶

Python 3.6 and Python 3.7 support has been dropped. Python 3.8 through Python 3.10 are now targeted for support.
PVAccess support has been removed, and caproto returns to being solely an EPICS Channel Access library.
Top-level utility functions for accessing pvAccess environment variables are now deprecated and will be reverted to pre-pvAccess (no protocol argument allowed) signatures in a future release.

Added / Fixed¶

Fixes for all Windows clients, servers, and the repeater relating to PV searches. recvfrom was occasionally raising ConnectionResetError, which on Windows only means that: “… a previous send operation resulted in an ICMP Port Unreachable message.” This is not fatal in caproto’s case and can safely be ignored (or worked around, in the case of asyncio). https://docs.microsoft.com/en-us/windows/win32/api/winsock/nf-winsock-recvfrom
Fixed pickle/copy for ChannelData subclasses
Fixed synchronous repeater bind address to INADDR_ANY (“0.0.0.0”). Binding to a specific interface meant that on Windows the repeater could not use its client-is-alive detection mechanism by binding to the client port as the bind would always succeed.
Updated method get_data_class() in PVSpec so that type maps are correct for read-only.
Use RotatingFileManager filename when restoring autosave.
Provide defaults for user limits in motor record simulation.
pvproperty no longer broken when decorating methods with docstring.
Type annotations have been added to caproto.server.server.
- pvproperty and PVSpec may now use the data class directly, instead of requiring an internal mapping of data type to class. For example, pvproperty(..., dtype=PvpropertyInteger) is allowed alongside the existing and less explicit pvproperty(..., dtype=int).
- Using such classes directly comes with the added benefit of type inference with your IDE’s language server / static analyzer. pyright and similar should be much happier with caproto IOCs that use pvproperty such that linting of attributes on pvproperty instances, features as “Go to source”, and code completion are now possible.

Development¶

Adjusted continuous integration jobs to reflect new supported versions.
Improved test suite reliability on continuous integration.
Removed buffer-slicing tools and tests in a refactor to avoid sendmsg on all platforms and async libraries.
Removed some old windows compatibility patches in caproto._windows_compat, and avoided monkey-patching for curio by moving its Windows-facing curio.run modification to caproto.curio.utils.curio_run.
Test suite has some built-in timeout-handling functionality on a per-async-library basis, avoiding exiting the entire test suite on Windows (due to limitations of pytest-timeout).
Trio socket handling has been updated to follow better practices for recent trio versions.

v0.8.1 (2021-06-03)¶

Fixed¶

pyepics compatibility layer should no longer leak a byte string value through for DBR_STRING PV instances. (#710, #763)

Added¶

Added support for raw EPICS timestamps in ChannelData instances, allowing for lossless representation and transmission of facility-specific beam fiducials, pulse IDs, and such. This feature is not intended to replace the current usage of POSIX (time.time()) timestamps, but rather extend what is considered to be acceptable input.

v0.8.0 (2021-03-18)¶

Fixed¶

pyepics compatibility layer char_value and enum_strs handling with PV instances and caget_many should now behave better. (#732)
Windows compatibility has been improved, especially with respect to the more recent ProactorEventLoop (#720, #707)
The environment variable CAPROTO_DEFAULT_TIMEOUT is no longer erroneously interpreted as a string. All clients should now mostly respect this value. (#727)
Previously only either scan or startup hooks were allowed per-pvproperty. Both may be used simultaneously now. (#729)
Threading client SharedBroadcaster should no longer attempt re-registration after it is disconnected. (#732)
RecordFieldGroup subclasses may now customize common fields without intefering with other classes. (#736)
Supports the numpy array interface to remove a significant O(n) bottleneck when pre-processing numpy arrays for ChannelByte instances. To avoid an additional copy on immutable data, set value.flags.writeable to False when using compatible numpy arrays. (#731)
safe_getsockname was stashing references to sockets and not allowing them to be garbage collected. (#739)
data_type values are now validated against ChannelType when used in commands. (#742)
Raise RemoteProtocolError with more user-friendly messages when invalid packets or those with invalid command IDs are received. (#743)
Synchronous client search erroneously used the same search ID for multiple requests. (#754)

Added¶

An example indicating how to analyze IOCs response times for channel creation was added in #725.
A value_write_hook is now supported when updating a value in records. This means that if the user updates .VAL, other fields will have the chance to update their state. (#734)
Added preliminary support of the raw_value (.RVAL) field for bi, bo, mbbi, and mbbo records. (#734)
Added sleep to AsyncLibraryLayer. (#739)
Added startup_hook to caproto.server.run() (with support in asyncio, curio, trio). By convention, consider using __ainit__ for this hook. (#739)
Added monitor helper to the asyncio client. (#739)
Now using GitHub actions for automated testing on Windows and macOS, with fixed documentation building and releasing to PyPI. This was defunct since Travis CI changed its payment model. (#749, #754)

Changed¶

The mock_record= keyword argument for pvproperty, deprecated in v0.5.0, has been removed. Please change any remaining references to record= when upgrading to v0.8.0.
Efforts have been made to allow PVSpec to be used in a standalone fashion - i.e., without pvproperty. See the no_pvproperty IOC example (ioc_examples/advanced) for further details.
asyncio-based transports have mostly been removed in favor of using a higher-level API provided by asyncio. This should allow for more precise and informative exception tracebacks. This is now used for all asyncio servers and clients supported by caproto. (#720)
The method for generating record field PVGroup classes has been changed to better split auto-generated code with user-customizable field-handling code. (#734)
Improved hook method signature checker to include source code filename, line number, and suggested signature. (#736)
Reworked IOC documentation and corresponding examples.
Old and bad form example all_in_one moved to testing area.
Old and bad form example inline_style moved to testing area.
Example using ChannelData type_varieties moved to “advanced”
On-class-definition validation of PvpropertyData keyword arguments was removed to reduce complexity. CaprotoRuntimeError will be raised on instantiation for pvproperties with bad keyword arguments, indicating the cause and full PVSpec information. (#741)
Warning messages when old CA clients are detected have been removed. The reasoning behind the message was likely flawed and will require further investigation. In the meantime, this will reduce log spam. (#757, #761)

v0.7.1 (2020-01-13)¶

Fixed¶

For pvproperty, avoid multiple passes of macro expansion, so {{ is now sufficient to escape curly brackets in PV names.
The server implementation will now catch when socket.recv raises OSError.
Broken entrypoints have been fixed for the pathological examples, defaultdict_server and spoof_beamline.

Added¶

Show default values for optional macro substitution for IOCs using the template parser.

Changed¶

Travis CI configuration has been removed from the repository.

v0.7.0 (2020-12-08)¶

Fixed¶

Eliminate memory leak on run-longing servers were we remembered every search request we saw but did not service
WaitForPlugins and additional PVs for compatibility were added in the fancy spoof_beamline example.
Many more libraries are now entirely optional in the test suite.
get_pv_pair_wrapper now supports keyword arguments to the generated pvproperty instances.

Added¶

Added documentation notes on multi-tenant soft IOCs.
Added helper tools for easily auto-generating PVGroup-based IOC documentation with sphinx-autosummary.
A fake motor record IOC example, with the most common fields implemented.
Added iocStats-like helpers for caproto-based IOCs, which include CPU/memory usage information, tools for finding memory leaks, and so on.
Add support for -# arguments in caproto-get and caproto-monitor command-line tools.
IntEnum values are now supported for pvproperty, simplifying declarations of enum PVs.
Added preliminary pvAccess support, including examples and documentation.
Added a shared memory IOC example.
Added a gamepad IOC example.
Added an IOC which generates PVs based on a formula string.
Added an escape hatch for pvproperty putters to skip further processing, the SkipWrite exception.

Changed¶

The search related API was removed from ca.Broadcaster, all of the search request accounting is handled in the client code. The code that is used on the servers can not do this book keeping because we can not know what other servers are out there and if the SearchRequest actually got serviced (as that goes back uni-cast).
Removed curio and trio client implementations. These may reappear in the future, based on the new asyncio client.
Removed unused dependency asks, which was part of the full installation.
Documentation is now versioned on GitHub pages thanks to doctr-versions-menu.
Automated benchmarking code which was previously part of the test suite, has been removed.
Unmaintained prototype-level clients based on trio and curio have been removed. The full-featured asyncio client from v0.6.0 is the suggested migration path.
IOC examples have been reorganized.
Updated continuous integration to use conda-forge epics-base.

v0.6.0 (2020-07-31)¶

Fixed¶

Fixed server PVGroup logger names. It was erroneously using the exact string ‘{base}.{log_name}’, and now will be correctly expanded to be based on either the module name or the parent PVGroup’s logger name.
Fields defined in the caproto.server.records.RecordFieldGroup may now be customized using, for example, @prop.fields.process_record.putter.
caproto.ChannelByte and caproto.ChannelChar with max_length=1 now accept scalar integer values, whereas they were previously failing due to expecting byte strings (or strings). This arose primarily in the case of record fields which attempt to reflect the actual data types found in epics-base.

Added¶

Added a new (experimental) asyncio client with features comparable to the threading client.
Allow caproto.server.SubGroup instances to accept keyword arguments.
Added autosave-like tools and an example.
Now using doctr-versions-menu for documentation.

Changed¶

Significantly refactored task handling in the asyncio server. This improves the performance of write request handling and overall task cleanup.
Some asyncio server utilities were relocated such that the server and new client can both utilize them.
Accessing a caproto.server.pvproperty directly from the caproto.server.PVGroup class will no longer return a caproto.server.PVSpec instance, but the caproto.server.pvproperty itself.

v0.5.2 (2020-06-18)¶

Fixed¶

Fixed a packaging issue introduced in 0.5.1 where some files were missing in the sdist source distribution package.
Prevent an error from occurring when trying to subscribe, with a callback, to a PV that is not yet connected. The subscription will now succeed and become active once the PV is fully connected.
Avoid duplicate registration of callbacks in Context.get_pvs().

v0.5.1 (2020-06-12)¶

Changed¶

Replaced usage of deprecated trio features with recommended approaches.
Updated curio-based server for compatibility with recent versions of curio. It is now incompatible with curio < 1.2.

Added¶

Added vel and mtr_tick_rate pvproperties to PinHole, Edge and Slit motors on mini beamline example, to provide control over the speed of the motors.
Added documentation on how to build and run caproto containers using buildah and podman.
Add a new test pip selector, as in pip install caproto[test], which installs caproto[complete] plus the requirements for running the tests.

v0.5.0 (2020-05-01)¶

Changed¶

In the threading client, the expected signature of Subscription callbacks has changed from f(response) to f(sub, response) where sub is the pertinent caproto.threading.client.Subscription. This change has been made in a backward-compatible way. Callbacks with the old signature, f(response), will still work but caproto will issue a warning. Support for the old signature may be removed in the future. By giving the callback f access to sub, we enable usages like
```
def f(sub, response):
    # Print the name of the pertinent PV.
    print('Received response from', sub.pv.name)

def f(sub, response):
    if ...:
        sub.remove_callback(f)
```
In the synchronous client, the expected signature of subscription callbacks has changed from f(response) to f(pv_name, response). As with the similar change to the threading client described above, this change was made an a backward-compatible way: the old signature is still accepted but a warning is issued.
The detail and formatting of the log messages has been improved.
The mock_record keyword argument to caproto.server.pvproperty has been deprecated, in favor of the simpler record.
EPICS record field support has been regenerated with a new database definition source. This reference .dbd file can be found in a separate repository here. These fields should now be more accurate than previous releases, including some initial values and better enum values, and also with basic round-trip tests verifying protocol compliance for each field.

Added¶

Added IOC server support for long string PVs.
- Channel Access maximum string length is 40 characters
- However, appending $ to DBF_STRING fields (e.g., MY:RECORD.DESC$) changes the request to DBF_CHAR, allowing for effectively unlimited length of strings.
- This is supported for caproto.server.pvproperty instances which are initialized with a string value (or specify caproto.ChannelType.STRING as the data type).
- This is supported internally by way of caproto._data.ChannelString, which adds an init keyword argument long_string_max_length.
Added documentation for fields of all supported record types.
Tools for automatically regenerating record fields and menus via a Jinja template are now included. See caproto.server.conversion.generate_all_records_jinja() and caproto.server.conversion.generate_all_menus_jinja() and the related jinja templates in caproto/server.

Fixed¶

On OSX, the creating a threading.client.Context pinned a CPU due to a busy socket selector loop.
When EPICS_CA_ADDR_LIST is set and nonempty and EPICS_CA_AUTO_ADDR_LIST=YES, the auto-detected addresses should be used in addition to the manually specified one. They were being used instead (with a warning issued).

v0.4.4 (2020-03-26)¶

Fixed¶

The fix for Python asyncio’s servers released in 0.4.3 had the accidental side-effect of preventing multiple servers from running on the same machine (or, to be precise, on the same network interface). This release fixes that regression.
Fix bug in caproto-put which made it impossible to set ENUM-type PVs.
Ensure that caproto servers respect the limits on the number of enum members and the length of enum streams.

v0.4.3 (2020-01-29)¶

Python releases 3.6.10, 3.7.6, and 3.8.1 made a breaking change for security reasons that happens to break caproto’s asyncio-based server (the default one) on all platforms. This release adjusts for that change. See asyncio.loop.create_datagram_endpoint() for details about this change in Python.

This release also fixes a bug introduced in v0.4.0 affecting Windows only that made caproto clients and servers unusuable on Windows.

v0.4.2 (2019-11-13)¶

This release contains some important bug fixes and some minor new features.

Features¶

Make the default timeout for the threading client configurable via the environment variable CAPROTO_DEFAULT_TIMEOUT. It was previously hard-coded to 2 (seconds).
Add --file argument to caproto-put, which obtains the value to be put from reading a file.
Link ZNAM and ONAM fields to the parent enum_strings.
Automatically populate pvproperty DESC using doc keyword argument.

Bug Fixes¶

Fix a critical race condition wherein data could be written into a buffer as it was being sent.
Propagate timeout specific to pyepics-compatible client to the next layer down.
Correctly handle reconnection if the server dies.
Allow asyncio server to do cleanup in all cases. (Previously, KeyboardInterrupt was erroneously exempted from cleanup.)
Let the server’s write method provide the timestamp. This is significant if the putter takes significant time to process or does any internal writes.

v0.4.1 (2019-10-06)¶

This release adds some small improvements and updates to address deprecations in Python and caproto’s optional dependencies.

Features¶

Added support for -S argument in the caproto-put commandline tool.
Added support for using Event synchronization primitives in servers, used in the new example caproto.ioc_examples.worker_thread_pc.

v0.4.0 (2019-06-06)¶

Features¶

Rewrite approach to logging. See Logging for details.
Add precision to motor_ph in mini_beamline example IOC.

Bug Fixes¶

Fix bug in scan_rate that raised errors when it was written to
Respond correctly when channel filter is set but empty.

v0.3.4 (2019-05-02)¶

Fixes¶

Several fixes and documentation for the commandline utilities’ formatting parameters added in v0.3.3.
Put an upper limit on how quickly a given search result may be reissued.
Documentation fix in server help string.

v0.3.3 (2019-04-11)¶

This release improves the commandline utilities’ parity to their counterparts in the reference implementation by supporting formatting parameters for integers and floats. It also includes some important fixes.

Fixes¶

When optional dependency netifaces is installed, clients search on all broadcast interfaces, not just 255.255.255.255. This reverts an erroneous change made in v0.2.3.
caproto-shark does a better job ignoring non-CA packets (instead of erroring out).

v0.3.2 (2019-03-06)¶

This release inclues just one minor fix to caproto-shark, enabling it to more reliably skip over irrelevant network traffic (i.e. traffic that is not Channel Access messages).

v0.3.1 (2019-03-05)¶

This is a bug-fix release addressing issues related to empty (zero-length) channel data.

Fixes¶

Fix servers’ support for empty (zero-length) data.
Assume the maximum length of a channel initialized with empty data is one (i.e. assume it is scalar).
Address an ambiguity in the Channel Access protocol: a subscription update (EventAddResponse) indicating empty data and a confirmation of a request to cancel the subscription (EventCancelResponse) serialize identically, and so the client must make a best effort to interpret based on context which of the two is intended.

v0.3.0 (2019-02-20)¶

This release introduces caproto-shark and other convenient improvements. It also contains many bug-fixes, some critical.

Features¶

Add Shark (pcap/tcpdump parsing).
Add server “healthcheck” methods to the threading client, which expose information collected about how recently each server has communicated with the client. See Server Health Check.
Add a new example IOC who PVs are dynamic (change during runtime). Include a “waveform” (array) PV in the simple example.
Make the default timeout configurable per Context and per PV, in addition to per a given operation. This makes it possible to adjust all the timeouts in one place during debugging.
Use a random starting ID for message identifiers as an extra layer of protections against collisions, especially in the context of CI testing where many clients and servers are started up in rapid succession.

Bug Fixes¶

Only attempt to use SO_REUSEPORT socket option if support for it has been compiled into Python.
A critical bug only affecting Windows had broken asyncio servers on Windows in a previous release.
The threading client was wrongly issuing warnings if it received multiple responses to a search for a PV from the same server.
Add missing user_offset pvproperty to MotorFields.
Fix several race conditions in the threading client.
Improve cleanup of resources: ensure sockets are explicitly closed and threads explicitly joined. (More work is needed, but progress was made.)
Fix “leak” of ioids (IO message identifiers).
Handle setting empty lists as values through the pyepics-compat client.
In the trio-backed server, remove usage of deprecated trio.Queue.
Many other small fixes and safeguards.

v0.2.3 (2019-01-02)¶

Usability Improvements¶

A new function set_handler() provides a convenient way to make common customizations to caproto’s default logging handler, such as writing to a file instead of the stdout.
In the threading client, store the current access rights level on the PV object as pv.access_rights. It was previously only accessible when it changed, via a callback, and had to be stashed/tracked by user code.
Display the version of caproto in the output of --help/-h in the commandline utilities. Add a new commandline argument --version/-V that outputs the version and exits.
In the threading client, DEBUG-log all read/write requests and read/write/event responses. (When these log messages were first introduced in v0.2.1, batched requests and their responses were not logged, and write responses were not logged when notify=True but wait=False.)

Bug Fixes¶

Fix critical bug in synchronous client that broke monitoring of multiple PVs.
Fix default (“AUTO”) broadcast address list (should always be 255.255.255.255). Removed internal utility function broadcast_address_list_from_interfaces().
In pyepics-compatible client, set default mask to SubscriptionType.DBE_VALUE | SubscriptionType.DBE_ALARM, consistent with pyepics.
Prevent subscriptions for being processed for all channels that share an alarm if the alarm state has not actually changed.

Updated Pyepics Compatibility¶

Added new method PV.get_with_metadata, which was added in pyepics 3.3.1.

Deprecations¶

The color_logs() convenience function has been deprecated in favor of set_handler().

Internal Changes¶

Enable -vvv (“very verbose”) option when running example IOCs in test suite.

v0.2.2 (2018-11-15)¶

The release improves the performance of the threading client and adds support for value-based alarms. Additionally, it provides more control over search and implements back-off in a way more consistent with (but not yet fully consistent with) EPICS’ reference implementation.

More Control Over Search¶

The threading client—and, thereby, the pyepics-compatible shim—have greater feature parity with epics-base.

In previous releases, the client resent any unanswered SearchRequests at a fast regular rate forever. Now, it backs off from that initial rate and rests at a slow interval to avoid creating too much wasteful network traffic. There is a new method, cancel(), for manually canceling some requests altogether if a response is never expected (e.g. a typo). There is also a new method for manually resending all unanswered search requests, search_now(), primarily for debugging. All unanswered search requests are automatically resent when the user searches for a new PV or when a new server appears on the network (see next point).
The client monitors server beacons to notice changes in the CA servers on the network. When a new server appears, all standing unanswered search requests are given a fresh start and immediately resent. If a server does not send a beacon within the expected interval and has also not sent any TCP packets related to user activity during that interval, the client silently initiates an Echo. If the server still does not respond, it is deemed unresponsive. The client logs a warning and disconnects all circuits from that server so that their PVs can begin attempting to reconnect to a responsive server.

Improved Alarm Support¶

Value-based alarms are supported by all servers.
LOLO, LO, HI, and HIHI alarm status fields of mocked records are respected.
Channel limit metadata (upper_alarm_limit, upper_warning_limit, etc.) is now integrated with alarms.

Bug Fixes and Performance Improvements¶

The socket settings SO_KEEPALIVE and TCP_NODELAY are used in the threading client TCP sockets, making it consistent with epics-base and removing a 40ms overhead that can occur when sending small packets.
Some unnecessary locking was removed from the threading client, resolving a deadlock observed in ophyd and improving performance.
The spoof_beamline IOC is aware of more components of Area Detector and defaults to float-type channels instead of integer-type.
A rare but possible race condition that caused a subscription to be activated twice (thus getting two responses for each update) has been resolved.
The ChannelData objects are serializable with pickle.
A bug in length-checking that affected zero-length data has been fixed.

The detail and consistency of the exceptions raised by the clients has also been improved.

v0.2.1 (2018-10-29)¶

This release tunes server performance under high load and fixes several subtle bugs in the server identified via acctst, the server acceptance test that ships with epics-base.

Bug Fixes¶

When a new Subscription is added, send the most recent value immediately but only to the new Subscription. Previous releases sent redundant messages to all Subscriptions that had similar parameters.
Reduce the maximum size of a datagram of search requests to match the typical Maximum Transmission Unit seen in the wild.
Fix a bug in the pyepics-compatibility layer that caused the connection callbacks never to be called when underlying caproto.threading.client.PV’s were reused.
Fix a typo in the PV names in the spoof_beamline IOC.
Never send an EventAddResponse after a matching EventCancelResponse has been sent.
Always send a response to a failed write, and include the correct error code.
If a circuit has an oversized backlog of received commands to process, log a WARNING before disconnecting.

Server Performance Tuning¶

Increase the max backlog of subscription updates queued up to send (both updates per specific Subscription and total updates per circuit) by a factor of 10. Likewise for the max backlog of received commands queued up to process.
When under sustained high load of subscription updates to send, iteratively double the latency between packets up to at most 1 second to achieve higher overall throughput (more commands per packet, less overhead).
When a Read[Notify]Request arrives on the heels of a Write[Notify]Request, wait for up to 0.001 seconds for the write to process before reading the current value. If the write happens to complete in less than 0.001 seconds, the read will reflect the new value. This behavior is in the spirit of, but distinct from, EPICS’ “synchronous writes.” EPICS allows a device to block while writing if it promises to finish quickly (< 0.1 milliseconds). We take a different approach, making all writes asynchronous. This ensures that an accidentally-slow write cannot lock up the server. It adds latency to some reads, up to a hard maximum of 1 millisecond, giving the effect of synchronous write whenever the write finishes fast.

The release also includes one small new feature: in the threading client, DEBUG-level logging of channels/PVs caproto.ch now logs (non-batch) read/write requests and read/write/event responses. [Update: In v0.2.3, this feature was extended to include batched requests and their responses.] Related — there is expanded documentation on Logging.

v0.2.0 (2018-10-17)¶

This release improves compliance with the protocol and server performance under high load.

Features¶

Under high load (with many subscription updates queued up to send) servers batch subscriptions into blocks, trading a little latency for efficiency. Under low load, servers prioritize low latency.
The servers’ medium-verbose setting (-v) displays current load and latency.
In the threading client, process user callbacks using one threadpool per circuit instead of one threadpool for the entire context. Make the size of the threadpool configurable via a new Context parameter, max_workers.
We now test the servers against a Python 3-compatible fork of Michael Davidsaver’s utility for testing Channel Access servers, catvs. This has generated several fixes improving protocol compliance, list a section below. There are a small number of known failures wherein the best/correct behavior is arguable; see caproto#327 on GitHub for discussion. There may be more progress on these in future releases of caproto.
Added pvproperty.scan. See the mini_beamline example IOC for a usage example.
Add a server-side data source for ChannelType.INT (a.k.a SHORT) data.
The default printed output of the caproto-monitor CLI utility now includes microseconds.
There are several new IOC examples.

Breaking Changes¶

The expected signature of the access_rights_callback passed to Context has been changed from f(access_rights) to f(pv, access_rights). This makes it consistent with the connection_callback.
If a beacon fails to send, do not kill the server; just log the failure, along with a suggestion on how to fix the environment to omit the failed address, and continue to run.
In the high-level server, implemented with pvproperty, PV values can be defined as scalars. The accessor pvproperty.value now returns a scalar instead of a length-1 list (API break), while write() accepts either list or scalar.

Bug Fixes¶

A critical bug CHAR-type payload serialization which made caproto clients unusable with CHAR-type channels has been fixed.
The asyncio server now executes its cleanup code when interrupted with SIGINT (Ctrl+C).
All three servers were relying on the operating system to clean up their sockets when the process exited. They now close their sockets explicitly when the server task exits. This fixes the runaway usage of file descriptors when the tests are run.

Improved Protocol Compliance¶

The servers send CreateChFailResponse when the client requests a channel name that does not exist on the server. They previously did not respond.
The servers reply to SearchRequest messages sent over TCP. (UDP is more common, but TCP is allowed.) They previously did not respond.
The EventCancelResponse message includes a data_count.
The servers respect the data_count requested by the client.
Servers enforce quota per subscription to avoid one prolific subscription (or slow client) from drowning out others.
Servers respect EventsOn and EventsOff requests.
Servers differentiate between current length and maximum length of an array, and they properly declare the maximum length in CreateChanResponse. They formerly declared the current length, which was not correct.
The caproto-put commandline utility now supports -a for arrays.

v0.1.2 (2018-08-31)¶

This is a bug-fix release fixing some critical bugs. We recommend that all users upgrade.

Fix critical typo in threading client’s search functionality that could cause it to conflate addresses from different search responses and then attempt to connect to the wrong server.
Fix handshake with servers and clients speaking Version 11 (or older) of the protocol.

v0.1.1 (2018-06-17)¶

This is a bug-fix release following closely on the initial release. We recommend that all users update.

Fix straightforward but important bug in the synchronous client that broke monitoring of multiple channels concurrently.
In servers, abide by the spec’s recommendation that beacons should be issued quickly at startup before backing off to a slower, steady rate.
Fix a bug that broke the array (“arr”) channel filter if numpy was not installed.
Add a new section to the documentation detailing caproto’s compliance with the Channel Access protocol and the feature parity of caproto’s clients and servers with respect to the reference implementations in epics-base.

v0.1.0 (2018-06-14)¶

This initial release contains some fairly stable components and some very experimental ones.

The core protocol code, the synchronous client, the threading client, and the pyepics-compatible client are fairly stable.
The high-level interface to IOCs has no known issues but could in a future release of caproto, as we gain experience from its use.
The three server implementations are thoroughly tested, but their low level API is likely to change in a future release.
The asynchronous client implementations (trio client and curio client) are highly experimental. They lack feature-parity with the other clients and have some known bugs. They may be heavily revised or removed in a future release of caproto.