ChillerClient¶

class lsst.ts.atwhitelight.ChillerClient(device_id, host, port, log)¶

Bases: Client

TCP/IP client for the chiller.

Parameters:

device_idstr: Device ID of the chiller. Typically “01”.
hoststr: TCP/IP host address of the chiller.
portint: TCP/IP port number of the chiller.
loglogging.Logger: Logger.

Attributes:

readerasyncio.StreamReader or None: Stream reader. If None then not connected.
writerasyncio.StreamWriter or None: Stream writer. If None then not connected.

Attributes Summary

connected

Return True if self._reader and self._writer are connected.

Methods Summary

`basic_close`()	Close the connected client socket, if any, and set done_task done.
`call_connect_callback`()	Call self.__connect_callback.
`close`()	Close the connected client socket, if any, and set done_task done.
`compute_checksum`(st)	Compute a checksum field as two ASCII hexadecimal bytes representing the sum of all previous bytes (8 bit summation, no carry) of the command starting with SOC
`format_full_command`(cmd)	Generate a full command with device ID and checksum.
`read`(n)	Read up to n bytes.
`read_into`(struct)	Read binary data from a stream reader into a `ctypes.Structure`.
`read_json`()	Read JSON data.
`read_str`()	Read and decode a terminated str; strip the terminator.
`readexactly`(n)	Read exactly n bytes.
`readline`()	Read a sequence of bytes ending with `\n`.
`readuntil`([separator])	Read one line, where “line” is a sequence of bytes ending with `separator`.
`run_command`(cmd)	Send a command and wait for the reply.
`start`(**kwargs)	Connect to the TCP/IP server.
`write`(data)	Write data and call `drain`.
`write_from`(*structs)	Write binary data from one or more `ctypes.Structure`s.
`write_json`(data)	Write data in JSON format.
`write_str`(line)	Encode, terminate, and write a str.
`writelines`(lines)	Write an iterable of bytes and call `drain`.

Attributes Documentation

connected¶

Return True if self._reader and self._writer are connected.

Note: if the other end drops the connection and if you are not trying to read data (e.g. in a background loop), then it takes the operating system awhile to realize the connection is lost. So this can return true for some unknown time after the connection has been dropped.

Methods Documentation

async basic_close() → None¶

Close the connected client socket, if any, and set done_task done.

Like close except does not clear self.should_be_connected, nor cancel self._monitor_connection_task.

async call_connect_callback() → None¶

Call self.__connect_callback.

This is always safe to call. It only calls the callback function if that function is not None and if the connection state has changed since the last time this method was called.

async close() → None¶

Close the connected client socket, if any, and set done_task done.

Call connect_callback if a client was connected.

static compute_checksum(st)¶

Compute a checksum field as two ASCII hexadecimal bytes representing the sum of all previous bytes (8 bit summation, no carry) of the command starting with SOC

Parameters:

ststr: ASCII string to be checksummed

Returns:

checksumstr: 2-character ASCII string

Raises:

UnicodeEncodeError: If st contains any non-ASCII characters.

format_full_command(cmd)¶

Generate a full command with device ID and checksum.

Format a command as “.{self.device_id}{cmd}(checksum}r” where checksum is for everything that comes before.

Parameters:

cmdstr: Command as string of 10-18 ASCII characters: the command ID followed by 8 chars of descriptive text and 0-8 characters of data payload.

Returns:

resultstr: Full command string.

async read(n: int) → bytes¶

Read up to n bytes.

Parameters:

nint: The number of bytes to read. If -1 then block until the other end closes its writer, then return all data seen.

Raises:

ConnectionError: If the connection is lost before, or while, reading.

async read_into(struct: Structure) → None¶

Read binary data from a stream reader into a ctypes.Structure.

Parameters:

structctypes.Structure: Structure to set.

Raises:

ConnectionError: If the connection is lost before, or while, reading.
asyncio.IncompleteReadError: If EOF is reached before n bytes can be read. Use the IncompleteReadError.partial attribute to get the partially read data.

async read_json() → Any¶

Read JSON data.

Read the data with read_str and return the json-decoded result.

Returns:

datatyping.Any: Data decoded from JSON.

Raises:

ConnectionError: If the connection is lost before, or while, reading.
asyncio.IncompleteReadError: If EOF is reached before the complete separator is found and the internal buffer is reset.
LimitOverrunError: If the amount of data read exceeds the configured stream lmit. The data is left in the internal buffer and can be read again.
TypeError: If the data are of a type that cannot be decoded from JSON.
json.JSONDecodeError: If the data cannot be decoded from JSON.

async read_str() → str¶

Read and decode a terminated str; strip the terminator.

Read until self.terminator, strip the terminator, and decode the data as self.encoding with strict error handling.

Returns:

linestr: Line of data, as a str with the terminator stripped.

Raises:

ConnectionError: If the connection is lost before, or while, reading.
asyncio.IncompleteReadError: If EOF is reached before the complete separator is found and the internal buffer is reset.
LimitOverrunError: If the amount of data read exceeds the configured stream lmit. The data is left in the internal buffer and can be read again.
UnicodeError: If decoding fails.

async readexactly(n: int) → bytes¶

Read exactly n bytes.

Parameters:

nint: The number of bytes to read.

Raises:

ConnectionError: If the connection is lost before, or while, reading.
asyncio.IncompleteReadError: If EOF is reached before n bytes can be read. Use the IncompleteReadError.partial attribute to get the partially read data.

async readline() → bytes¶

Read a sequence of bytes ending with \n.

If EOF is received and \n was not found, the method returns partially read data.

Raises:

ConnectionError: If the connection is lost before, or while, reading.

async readuntil(separator: bytes = b'\n') → bytes¶

Read one line, where “line” is a sequence of bytes ending with separator.

Read data from the stream until separator is found.

On success, the data and separator will be removed from the internal buffer (consumed). Returned data will include the separator at the end.

See also read_str, which is more convenient for most use cases.

Parameters:

separatorbytes: The desired separator. The default matches the standard library, rather than using terminator.

Raises:

ConnectionError: If the connection is lost before, or while, reading.
asyncio.IncompleteReadError: If EOF is reached before the complete separator is found and the internal buffer is reset.
LimitOverrunError: If the amount of data read exceeds the configured stream lmit. The data is left in the internal buffer and can be read again.

async run_command(cmd)¶

Send a command and wait for the reply.

Parameters:

cmdstr: Command, with no device ID or checksum.

Returns:

replystr: The reply, without the trailing checksum and

.

async start(**kwargs: Any) → None¶

Connect to the TCP/IP server.

This is called automatically by the constructor, and is not intended to be called by the user. It is a public method so that subclasses can override it.

Parameters:

**kwargsdict [str, typing.Any]: Additional keyword arguments for asyncio.open_connection, beyond host and port.

Raises:

RuntimeError: If start already called.

async write(data: bytes) → None¶

Write data and call drain.

Parameters:

databytes: The data to write.

Raises:

ConnectionError: If self.connected false before writing begins.

async write_from(*structs: Structure) → None¶

Write binary data from one or more ctypes.Structures.

Parameters:

structslist [ctypes.Structure]: Structures to write.

Raises:

ConnectionError: If self.connected false before writing begins.

async write_json(data: Any) → None¶

Write data in JSON format.

Encode the data as json and write the result with write_str.

Parameters:

dataany: The data to be written. Typically a dict, but any json-encodable data is acceptable.

Raises:

ConnectionError: If the connection is lost before, or while, reading.
UnicodeError: If encoding fails.
json.JSONEncodeError: If the data cannot be json-encoded.

async write_str(line: str) → None¶

Encode, terminate, and write a str.

Encode the str as self.encoding with strict error handling, and append self.terminator.

Parameters:

linestr: The line of data to be written.

Raises:

ConnectionError: If the connection is lost before, or while, reading.
UnicodeError: If encoding fails.

async writelines(lines: Iterable) → None¶

Write an iterable of bytes and call drain.

Parameters:

linescollections.abc.Iterable [bytes]: The data to write, as an iterable collection of bytes.

Raises:

ConnectionError: If self.connected false before writing begins.

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ChillerClient¶