glance.image_cache package¶
Subpackages¶
Submodules¶
Module contents¶
LRU Cache for Image Data
-
class
glance.image_cache.
ImageCache
[source]¶ Bases:
object
Provides an LRU cache for image data.
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cache_image_file
(image_id, image_file)[source]¶ Cache an image file.
- Parameters
image_id – Image ID
image_file – Image file to cache
- Returns
True if image file was cached, False otherwise
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cache_image_iter
(image_id, image_iter, image_checksum=None)[source]¶ Cache an image with supplied iterator.
- Parameters
image_id – Image ID
image_file – Iterator retrieving image chunks
image_checksum – Checksum of image
- Returns
True if image file was cached, False otherwise
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clean
(stall_time=None)[source]¶ Cleans up any invalid or incomplete cached images. The cache driver decides what that means…
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configure_driver
()[source]¶ Configure the driver for the cache and, if it fails to configure, fall back to using the SQLite driver which has no odd dependencies
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delete_all_cached_images
()[source]¶ Removes all cached image files and any attributes about the images and returns the number of cached image files that were deleted.
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delete_all_queued_images
()[source]¶ Removes all queued image files and any attributes about the images and returns the number of queued image files that were deleted.
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delete_cached_image
(image_id)[source]¶ Removes a specific cached image file and any attributes about the image
- Parameters
image_id – Image ID
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delete_queued_image
(image_id)[source]¶ Removes a specific queued image file and any attributes about the image
- Parameters
image_id – Image ID
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get_caching_iter
(image_id, image_checksum, image_iter)[source]¶ Returns an iterator that caches the contents of an image while the image contents are read through the supplied iterator.
- Parameters
image_id – Image ID
image_checksum – checksum expected to be generated while iterating over image data
image_iter – Iterator that will read image contents
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get_hit_count
(image_id)[source]¶ Return the number of hits that an image has
- Parameters
image_id – Opaque image identifier
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get_image_size
(image_id)[source]¶ Return the size of the image file for an image with supplied identifier.
- Parameters
image_id – Image ID
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get_queued_images
()[source]¶ Returns a list of image IDs that are in the queue. The list should be sorted by the time the image ID was inserted into the queue.
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is_cached
(image_id)[source]¶ Returns True if the image with the supplied ID has its image file cached.
- Parameters
image_id – Image ID
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is_queued
(image_id)[source]¶ Returns True if the image identifier is in our cache queue.
- Parameters
image_id – Image ID
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open_for_read
(image_id)[source]¶ Open and yield file for reading the image file for an image with supplied identifier.
- :note Upon successful reading of the image file, the image’s
hit count will be incremented.
- Parameters
image_id – Image ID
-