Miscellaneous modules

utils – utilities

Utility functions and classes.

summer.utils.locate_file(path_to_module: str, filename: str) → str[source]

Tries to locate the file in module path. Starts the search in current directory and goes up in directory structure until file is found or module namespace is left.

Parameters

  • path_to_module (str) – directory path, ususally just pass in __file__ built-in

  • filename (str) – file to look for

FIXME martin.slouf – now it only checks 3 levels up, instead of end of module namespace.

summer.utils.chunks(col: collections.abc.Iterable, chunk_size: int)[source]

Yield successive n-sized chunks from iterable.

Thanks to: http://stackoverflow.com/questions/312443/how-do-you-split-a-list-into-evenly-sized-chunks-in-python

Parameters

  • col (collections.Iterable) – collection to be chunked

  • chunk_size (int) – chunk size

Returns

generator over collection of chunks

(collection of original elements split into several smaller collections of chunk_size length)

Return type

types.GeneratorType

class summer.utils.Printable[source]

Bases: object

Tries to pretty print object properties into a unicode string.

Suitable for multi-inheritance, see summer.model.Domain.

__str__()[source]

Return printable object string representation in unicode.

__bytes__()[source]

Return printable object representation in platform specific encoding.

__repr__()[source]

Return repr(self).

__weakref__

list of weak references to the object (if defined)

class summer.utils.FileReader(fin: io.IOBase, enc: str)[source]

Bases: object

Simple & handy class for reading text file line by line with specified encoding. Converts line read to unicode. Counts line read. Does no file manipulation (opening, closing) except for reading. If used, you should delegate all reading to this simple class.

__init__(fin: io.IOBase, enc: str)[source]

Creates the FileReader instance.

Parameters

  • fin (io.IOBase) – file-like object to be read

  • enc (str) – file encoding

readline() → str[source]

Read single line from a file.

Returns

line as unicode string.

Return type

str

__weakref__

list of weak references to the object (if defined)

class summer.utils.ThreadSafeCounter(initial_value=0)[source]

Bases: object

Thread safe counter.

__init__(initial_value=0)[source]

Creates ThreadSafeCounter instance.

Parameters

initial_value (int) – initial value

inc(increase_by: int = 1) → int[source]

Increase counter by 1 and return new value.

dec(decrease_by: int = 1) → int[source]

Decrease counter by 1 and return new value.

__weakref__

list of weak references to the object (if defined)

class summer.utils.IdGenerator[source]

Bases: object

Thread safe id generator.

__init__()[source]

Initialize self. See help(type(self)) for accurate signature.

gen_id() → int[source]

Generates new id.

Returns

new id

Return type

int

__weakref__

list of weak references to the object (if defined)

class summer.utils.Singleton[source]

Bases: type

Metaclass that makes the class producing singleton instance.

__call__(*args, **kwargs)[source]

Call self as a function.

class summer.utils.ConfigValue[source]

Bases: object

Configuration class that defines a default value while checking the os environment os.environ for a possible override.

__init__()[source]

Initialize self. See help(type(self)) for accurate signature.

__str__()[source]

Return str(self).

__call__(env_variable_name: str, default_value: object) → object[source]

Call self as a function.

convert_value_str(value_str: str, target_class: type) → object[source]

Utility method that converts a string value to proper type

Parameters

  • value_str (str) – value to be converted

  • target_class (type) – required target type

Returns

Converted value or original one, if no conversion found.

Return type

object

__weakref__

list of weak references to the object (if defined)

stringutils – string utilities

Utility string functions that should be probably part of Python stdlib.

EMPTY_STRING defines an empty string (ie. “”)

This module is not imported into public summer namespace, so you should import it directly:

from summer import stringutils
summer.stringutils.has_text(obj: object, strip: bool = True) → bool[source]

Check for text in string.

Parameters

  • obj (object) – object to be tested

  • strip (bool) – if True obj is stripped before checking

Returns

True if obj is string and contains some non-white

characters; False otherwise.

Return type

bool

summer.stringutils.to_unicode(obj: object, encoding: str) → str[source]

Return unicode representation of an object.

Returns

unicoce string object representation

Return type

str

summer.stringutils.wrap(text: str, width: int) → str[source]

A word-wrap function that preserves existing line breaks and most spaces in the text. Expects that existing line breaks are posix newlines (\n).

Taken from: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/148061/index_txt

Parameters

  • text (str) – text to be wrapped

  • width (int) – max number of characters in single line

Returns

wrapped original text

Return type

str

ipythonutils – ipython debugging support

Support for embedded IPython invocation.

This module is not imported into public summer namespace, so you should import it directly:

from summer import ipythonutils
summer.ipythonutils.run_ipshell(banner: str = None, local_variables: dict = None)[source]

Runs an embedded IPython interpretter at the place of your call.

To invoke the interpreter at the place of your choice:

from summer.ipythonutils import run_ipshell
run_ipshell()
Parameters

  • banner (str) – banner (greeting) to be used

  • local_variables (dict) – dictionary of variables accessible through l variable in invoked shell, defaults to current locals()

ass – assert

Provides various pre-implemented simple tests (ie. asserts) suitable for input argument testing.

This module is not imported into public summer namespace, so you should import it directly:

from summer import ass
exception summer.ass.AssertException(message: str = None, **kwargs)[source]

Bases: summer.ex.ApplicationException

Raised when some of the assertions methods in this module fails.

__init__(message: str = None, **kwargs)[source]

Creates ApplicationException instance.

Parameters

  • message (str) – message to be printed

  • kwargs – keyword arguments are printed as are, suitable for providing some context (current values of important variables and such.

summer.ass.is_none(obj: object, msg: str = None, **kwargs) → bool[source]
Parameters

  • obj (object) – object instance to be tested

  • msg (str) – message in exception if test fails

  • kwargs – arguments forwarded to exceptions (usually context values that are presented in stacktrace alongside the message.

Returns

True if obj is None, False otherwise.

Return type

bool

summer.ass.is_not_none(obj: object, msg: str = None, **kwargs) → bool[source]
Parameters

  • obj (object) – object instance to be tested

  • msg (str) – message in exception if test fails

  • kwargs – arguments forwarded to exceptions (usually context values that are presented in stacktrace alongside the message.

Returns

True if obj is not None, False otherwise.

Return type

bool

summer.ass.is_true(expr: bool, msg: str = None, **kwargs) → bool[source]
Parameters

  • expr (bool) – object instance to be tested

  • msg (str) – message in exception if test fails

  • kwargs – arguments forwarded to exceptions (usually context values that are presented in stacktrace alongside the message.

Returns

True if expr is True, False otherwise.

Return type

bool

summer.ass.is_false(expr: bool, msg: str = None, **kwargs) → bool[source]
Parameters

  • expr (bool) – object instance to be tested

  • msg (str) – message in exception if test fails

  • kwargs – arguments forwarded to exceptions (usually context values that are presented in stacktrace alongside the message.

Returns

True if expr is False, False otherwise.

Return type

bool

summer.ass.has_text(obj: str, msg: str = None, **kwargs) → bool[source]
Parameters

  • obj (str) – object instance to be tested

  • msg (str) – message in exception if test fails

  • kwargs – arguments forwarded to exceptions (usually context values that are presented in stacktrace alongside the message.

Returns

True if obj is str and is not empty, False otherwise.

Return type

bool

lod – list of dictionaries

List of dictionaries (lod) – simple yet powerfull in memory data structure, ie. grid.

Thanks to: http://stackoverflow.com/questions/1038160/python-data-structure-for-maintaing-tabular-data-in-memory

This module is not imported into public summer namespace, so you should import it directly:

from summer import lod
summer.lod.lod_populate(lod: list, fin: io.IOBase)[source]

Populate lod using CSV file.

Parameters

  • lod (list) – list to be extended with data

  • fin (io.IOBase) – file-like object in CSV format

summer.lod.lod_query(lod: list, filter_obj=None, sort_keys=None)[source]

Lookup in lod based on query.

Parameters

  • lod (list) – lod to be used

  • filter_obj – filter to be used

  • sort_keys – sort criteria

Returns

collection of matching rows

Return type

list

summer.lod.lod_lookup(lod: list, **kw)[source]

Lookup in lod by attribute values.

Parameters

  • lod (list) – lod to be used

  • **kw (dict) – use keyword arguments. keys are column names, their value is attribute value

Returns

first matching row

Return type

list