Recorders

class pikos.recorders.abstract_recorder.AbstractRecorder

Bases: object

Abstract recorder class.

A recorder is reposnible for storing the record data that are provided by the monitor or profiler. The records are expected to be nametuple-like classes.

prepare(record)

Perform any setup required before the recorder is used.

Parameters:record (NamedTuple) – The record class that is going to be used.

finalize()

Perform any tasks to finalize and clean up when the recording has completed.

record(data)

Record a measurement.

Parameters:data (NamedTuple) – An instance of the record class that is going to be used.

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class pikos.recorders.csv_recorder.CSVRecorder(stream, filter_=None, **csv_kwargs)

Bases: pikos.recorders.abstract_recorder.AbstractRecorder

The CSV Recorder is a simple text based recorder that records the tuple of values using a scv writer.

Private

_filter = callable

Used to check if the set record should be recorded. The function accepts a tuple of the record values and return True is the input sould be recored.

_writer = csv.writer

The writer object is owned by the CSVRecorder and exports the record values according to the configured dialect.

_ready = bool

Singify that the Recorder is ready to accept data.

__init__(stream, filter_=None, **csv_kwargs)

Class initialization.

Parameters:

• stream (file) – A file-like object to use for output.
• filter (callable) – A callable function that accepts a data tuple and returns True if the input sould be recorded.
• **csv_kwargs – Key word arguments to be passed to the cvs.writer.

prepare(record)

Write the header in the csv file the first time it is called.

finalize()

Finalize the recorder.

A do nothing method.

Raises:RecorderError – Raised if the method is called without the recorder been ready to accept data.

record(data)

Record the data entry when the filter function returns True.

Parameters:values (NamedTuple) – The record entry. Raises:RecorderError – Raised if the method is called without the recorder been ready to accept data.

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class pikos.recorders.list_recorder.ListRecorder(filter_=None)

Bases: pikos.recorders.abstract_recorder.AbstractRecorder

The ListRecorder is simple recorder that records the tuple of values in memory as a list.

Public

records = list

List of records. The Recorder assumes that the record method is provided with a tuple and accumulates all the records in a list.

Private

_filter = callable

Used to check if the data entry should be recorded. The function accepts a namedtuple record and return True is the input sould be recored.

__init__(filter_=None)

Class initialization.

Parameters:filter (callable) – A callable function to filter out the data entries that are going to be recorded.

prepare(record)

Prepare the recorder to accept data.

Note

nothing to do for the ListRecorder.

finalize()

Finalize the recorder.

Note

nothing to do for the ListRecorder.

ready

Is the recorder ready to accept data?

record(data)

Record the data entry when the filter function returns True.

Parameters:data (NamedTuple) – The record entry.

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class pikos.recorders.text_stream_recorder.TextStreamRecorder(text_stream, filter_=None, formatted=False, auto_flush=False)

Bases: pikos.recorders.abstract_recorder.AbstractRecorder

The TextStreamRecorder is simple recorder that formats and writes the records directly to a stream.

Private

_stream = TextIOBase

A text stream what supports the TextIOBase interface. The Recorder will write the values as a single line.

_filter = callable

Used to check if the set record should be recorded. The function accepts a tuple of the record values and return True is the input should be recorded.

_template = str

A string (using the Format Specification Mini-Language) to format the set of values in a line. It is constructed when the prepare method is called.

_auto_flush = bool

A bool to enable/disable automatic flushing of the string after each record process.

_ready = bool

Signify that the Recorder is ready to accept data.

__init__(text_stream, filter_=None, formatted=False, auto_flush=False)

Class initialization.

Parameters:

• text_stream (TextIOBase) – A text stream what supports the TextIOBase interface.
• filter (callable) – A callable function that accepts a data tuple and returns True if the input sould be recorded.
• formatted (Bool) – Use the predefined formatting in the records. Default value is false.
• auto_flush (Bool) – When set the stream buffer is always flushed after each record process. Default value is False.

prepare(record)

Prepare the recorder to accept data.

Parameters:data (NamedTuple) – An example record to prepare the recorder and write the header to the stream.

finalize()

Finalize the recorder

A do nothing method.

Raises:RecorderError – Raised if the method is called without the recorder been ready to accept data.

record(data)

Rerord the data entry when the filter function returns True.

Parameters:data (NamedTuple) – The record entry. Raises:RecorderError – Raised if the method is called without the recorder been ready to accept data.

Note

Given the value of _auto_flush the recorder will flush the stream buffers after each record.

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