CedarBackup3.extend.capacity

Provides an extension to check remaining media capacity.

Some users have asked for advance warning that their media is beginning to fill up. This is an extension that checks the current capacity of the media in the writer, and prints a warning if the media is more than X% full, or has fewer than X bytes of capacity remaining.

author

Kenneth J. Pronovici <pronovic@ieee.org>

Module Contents

CedarBackup3.extend.capacity.logger

class CedarBackup3.extend.capacity.PercentageQuantity(quantity=None)

Bases: object

Class representing a percentage quantity.

The percentage is maintained internally as a string so that issues of precision can be avoided. It really isn’t possible to store a floating point number here while being able to losslessly translate back and forth between XML and object representations. (Perhaps the Python 2.4 Decimal class would have been an option, but I originally wanted to stay compatible with Python 2.3.)

Even though the quantity is maintained as a string, the string must be in a valid floating point positive number. Technically, any floating point string format supported by Python is allowble. However, it does not make sense to have a negative percentage in this context.

quantity

percentage

__repr__()

Official string representation for class instance.

__str__()

Informal string representation for class instance.

__eq__(other)

Equals operator, iplemented in terms of original Python 2 compare operator.

__lt__(other)

Less-than operator, iplemented in terms of original Python 2 compare operator.

__gt__(other)

Greater-than operator, iplemented in terms of original Python 2 compare operator.

__cmp__(other)

Original Python 2 comparison operator. Lists within this class are “unordered” for equality comparisons. :param other: Other object to compare to

Returns

-1/0/1 depending on whether self is <, = or > other

class CedarBackup3.extend.capacity.CapacityConfig(maxPercentage=None, minBytes=None)

Bases: object

Class representing capacity configuration.

The following restrictions exist on data in this class:

• The maximum percentage utilized must be a PercentageQuantity

• The minimum bytes remaining must be a ByteQuantity

maxPercentage

minBytes

__repr__()

Official string representation for class instance.

__str__()

Informal string representation for class instance.

__eq__(other)

Equals operator, iplemented in terms of original Python 2 compare operator.

__lt__(other)

Less-than operator, iplemented in terms of original Python 2 compare operator.

__gt__(other)

Greater-than operator, iplemented in terms of original Python 2 compare operator.

__cmp__(other)

Original Python 2 comparison operator. :param other: Other object to compare to

Returns

-1/0/1 depending on whether self is <, = or > other

class CedarBackup3.extend.capacity.LocalConfig(xmlData=None, xmlPath=None, validate=True)

Bases: object

Class representing this extension’s configuration document.

This is not a general-purpose configuration object like the main Cedar Backup configuration object. Instead, it just knows how to parse and emit specific configuration values to this extension. Third parties who need to read and write configuration related to this extension should access it through the constructor, validate and addConfig methods.

Note: Lists within this class are “unordered” for equality comparisons.

capacity

__repr__()

Official string representation for class instance.

__str__()

Informal string representation for class instance.

__eq__(other)

Equals operator, iplemented in terms of original Python 2 compare operator.

__lt__(other)

Less-than operator, iplemented in terms of original Python 2 compare operator.

__gt__(other)

Greater-than operator, iplemented in terms of original Python 2 compare operator.

__cmp__(other)

Original Python 2 comparison operator. Lists within this class are “unordered” for equality comparisons. :param other: Other object to compare to

Returns

-1/0/1 depending on whether self is <, = or > other

validate()

Validates configuration represented by the object. THere must be either a percentage, or a byte capacity, but not both. :raises ValueError: If one of the validations fails

addConfig(xmlDom, parentNode)

Adds a <capacity> configuration section as the next child of a parent.

Third parties should use this function to write configuration related to this extension.

We add the following fields to the document:

maxPercentage  //cb_config/capacity/max_percentage
minBytes       //cb_config/capacity/min_bytes

Parameters

• xmlDom – DOM tree as from impl.createDocument()

• parentNode – Parent that the section should be appended to

CedarBackup3.extend.capacity.executeAction(configPath, options, config)

Executes the capacity action.

Parameters

• configPath (String representing a path on disk) – Path to configuration file on disk

• options (Options object) – Program command-line options

• config (Config object) – Program configuration

Raises

• ValueError – Under many generic error conditions

• IOError – If there are I/O problems reading or writing files