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authorValentin Rothberg <rothberg@redhat.com>2020-09-11 14:43:57 +0200
committerValentin Rothberg <rothberg@redhat.com>2020-09-11 14:48:56 +0200
commitf867d27ae02aa678a94e7a3e42671914025f4b3d (patch)
tree7c710646a60787e13736f99d9ebf09ffad15fa7f /libpod
parent397de44d487e25b5820777fcbab9728cf2af5e14 (diff)
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system df: fix image-size calculations
Fix the image-size calculations of system-df, where the shared size is the actual shared size with other images (including children) and the (total) size is the sum of the shared and unique size [1]. To calculate parent/child relations, make use of the recently added layer tree which allows for quick (and cached!) calculations. Break calculating image disk usages into the image runtime to a) access the layer tree, and b) make the code easier to maintain and extend. [1] https://docs.docker.com/engine/reference/commandline/system_df/ Fixes: #7406 Signed-off-by: Valentin Rothberg <rothberg@redhat.com>
Diffstat (limited to 'libpod')
-rw-r--r--libpod/image/df.go126
1 files changed, 126 insertions, 0 deletions
diff --git a/libpod/image/df.go b/libpod/image/df.go
new file mode 100644
index 000000000..84cf7af9e
--- /dev/null
+++ b/libpod/image/df.go
@@ -0,0 +1,126 @@
+package image
+
+import (
+ "context"
+ "time"
+
+ "github.com/containers/image/v5/docker/reference"
+)
+
+// DiskUsageStat gives disk-usage statistics for a specific image.
+type DiskUsageStat struct {
+ // ID of the image.
+ ID string
+ // Repository of the first recorded name of the image.
+ Repository string
+ // Tag of the first recorded name of the image.
+ Tag string
+ // Created is the creation time of the image.
+ Created time.Time
+ // SharedSize is the amount of space shared with another image.
+ SharedSize uint64
+ // UniqueSize is the amount of space used only by this image.
+ UniqueSize uint64
+ // Size is the total size of the image (i.e., the sum of the shared and
+ // unique size).
+ Size uint64
+ // Number of containers using the image.
+ Containers int
+}
+
+// DiskUsage returns disk-usage statistics for the specified slice of images.
+func (ir *Runtime) DiskUsage(ctx context.Context, images []*Image) ([]DiskUsageStat, error) {
+ stats := make([]DiskUsageStat, len(images))
+
+ // Build a layerTree to quickly compute (and cache!) parent/child
+ // relations.
+ tree, err := ir.layerTree()
+ if err != nil {
+ return nil, err
+ }
+
+ // Calculate the stats for each image.
+ for i, img := range images {
+ stat, err := diskUsageForImage(ctx, img, tree)
+ if err != nil {
+ return nil, err
+ }
+ stats[i] = *stat
+ }
+
+ return stats, nil
+}
+
+// diskUsageForImage returns the disk-usage statistics for the spcified image.
+func diskUsageForImage(ctx context.Context, image *Image, tree *layerTree) (*DiskUsageStat, error) {
+ stat := DiskUsageStat{
+ ID: image.ID(),
+ Created: image.Created(),
+ }
+
+ // Repository and tag.
+ var name, repository, tag string
+ for _, n := range image.Names() {
+ if len(n) > 0 {
+ name = n
+ break
+ }
+ }
+ if len(name) > 0 {
+ named, err := reference.ParseNormalizedNamed(name)
+ if err != nil {
+ return nil, err
+ }
+ repository = named.Name()
+ if tagged, isTagged := named.(reference.NamedTagged); isTagged {
+ tag = tagged.Tag()
+ }
+ } else {
+ repository = "<none>"
+ tag = "<none>"
+ }
+ stat.Repository = repository
+ stat.Tag = tag
+
+ // Shared, unique and total size.
+ parent, err := tree.parent(ctx, image)
+ if err != nil {
+ return nil, err
+ }
+ childIDs, err := tree.children(ctx, image, false)
+ if err != nil {
+ return nil, err
+ }
+ // Optimistically set unique size to the full size of the image.
+ size, err := image.Size(ctx)
+ if err != nil {
+ return nil, err
+ }
+ stat.UniqueSize = *size
+
+ if len(childIDs) > 0 {
+ // If we have children, we share everything.
+ stat.SharedSize = stat.UniqueSize
+ stat.UniqueSize = 0
+ } else if parent != nil {
+ // If we have no children but a parent, remove the parent
+ // (shared) size from the unique one.
+ size, err := parent.Size(ctx)
+ if err != nil {
+ return nil, err
+ }
+ stat.UniqueSize -= *size
+ stat.SharedSize = *size
+ }
+
+ stat.Size = stat.SharedSize + stat.UniqueSize
+
+ // Number of containers using the image.
+ containers, err := image.Containers()
+ if err != nil {
+ return nil, err
+ }
+ stat.Containers = len(containers)
+
+ return &stat, nil
+}