copy: add --dest-compress-format and --dest-compress-level

add the possibility to specify the format and the level to use when
compressing blobs.

Signed-off-by: Giuseppe Scrivano <[email protected]>

cmd/skopeo/utils.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"strings"
 
+	"github.com/containers/image/pkg/compression"
 	"github.com/containers/image/transports/alltransports"
 	"github.com/containers/image/types"
 	"github.com/urfave/cli"
@@ -153,9 +154,11 @@ func (opts *imageOptions) newSystemContext() (*types.SystemContext, error) {
 // imageDestOptions is a superset of imageOptions specialized for iamge destinations.
 type imageDestOptions struct {
 	*imageOptions
-	osTreeTmpDir                string // A directory to use for OSTree temporary files
-	dirForceCompression         bool   // Compress layers when saving to the dir: transport
-	ociAcceptUncompressedLayers bool   // Whether to accept uncompressed layers in the oci: transport
+	osTreeTmpDir                string      // A directory to use for OSTree temporary files
+	dirForceCompression         bool        // Compress layers when saving to the dir: transport
+	ociAcceptUncompressedLayers bool        // Whether to accept uncompressed layers in the oci: transport
+	compressionFormat           string      // Format to use for the compression
+	compressionLevel            optionalInt // Level to use for the compression
 }
 
 // imageDestFlags prepares a collection of CLI flags writing into imageDestOptions, and the managed imageDestOptions structure.
@@ -179,6 +182,16 @@ func imageDestFlags(global *globalOptions, shared *sharedImageOptions, flagPrefi
 			Usage:       "Allow uncompressed image layers when saving to an OCI image using the 'oci' transport. (default is to compress things that aren't compressed)",
 			Destination: &opts.ociAcceptUncompressedLayers,
 		},
+		cli.StringFlag{
+			Name:        flagPrefix + "compress-format",
+			Usage:       "`FORMAT` to use for the compression",
+			Destination: &opts.compressionFormat,
+		},
+		cli.GenericFlag{
+			Name:  flagPrefix + "compress-level",
+			Usage: "`LEVEL` to use for the compression",
+			Value: newOptionalIntValue(&opts.compressionLevel),
+		},
 	}...), &opts
 }
 
@@ -193,6 +206,17 @@ func (opts *imageDestOptions) newSystemContext() (*types.SystemContext, error) {
 	ctx.OSTreeTmpDirPath = opts.osTreeTmpDir
 	ctx.DirForceCompress = opts.dirForceCompression
 	ctx.OCIAcceptUncompressedLayers = opts.ociAcceptUncompressedLayers
+	if opts.compressionFormat == "" {
+		opts.compressionFormat = "gzip"
+	}
+	cf, err := compression.AlgorithmByName(opts.compressionFormat)
+	if err != nil {
+		return nil, err
+	}
+	ctx.CompressionFormat = cf
+	if opts.compressionLevel.present {
+		ctx.CompressionLevel = &opts.compressionLevel.value
+	}
 	return ctx, err
 }
 

docs/skopeo-copy.1.md

@@ -58,6 +58,10 @@ If the authorization state is not found there, $HOME/.docker/config.json is chec
 
 Existing signatures, if any, are preserved as well.
 
+**--dest-compress-format** _format_ Specifies the compression format to use.
+
+**--dest-compress-level** _format_ Specifies the compression level to use.  The value is specific to the compression algorithm used, e.g. for zstd the accepted values are in the range 1-20 (inclusive), while for gzip it is 1-9 (inclusive).  Algorithms that don't support the setting, will ignore it.
+
 ## EXAMPLES
 
 To copy the layers of the docker.io busybox image to a local directory:

go.mod

@@ -4,6 +4,7 @@ go 1.12
 
 require (
 	github.com/BurntSushi/toml v0.3.1 // indirect
+	github.com/DataDog/zstd v1.4.0 // indirect
 	github.com/Microsoft/go-winio v0.4.12 // indirect
 	github.com/Microsoft/hcsshim v0.8.6 // indirect
 	github.com/VividCortex/ewma v1.1.1 // indirect
@@ -64,3 +65,5 @@ require (
 	gopkg.in/yaml.v2 v2.0.0-20141029210843-d466437aa4ad // indirect
 	k8s.io/client-go v0.0.0-20181219152756-3dd551c0f083 // indirect
 )
+
+replace github.com/containers/image => github.com/giuseppe/image v0.0.0-20190717145617-e25c2090aca9

go.sum

@@ -1,5 +1,7 @@
 github.com/BurntSushi/toml v0.3.1 h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
+github.com/DataDog/zstd v1.4.0 h1:vhoV+DUHnRZdKW1i5UMjAk2G4JY8wN4ayRfYDNdEhwo=
+github.com/DataDog/zstd v1.4.0/go.mod h1:1jcaCB/ufaK+sKp1NBhlGmpz41jOoPQ35bpF36t7BBo=
 github.com/Microsoft/go-winio v0.4.12 h1:xAfWHN1IrQ0NJ9TBC0KBZoqLjzDTr1ML+4MywiUOryc=
 github.com/Microsoft/go-winio v0.4.12/go.mod h1:VhR8bwka0BXejwEJY73c50VrPtXAaKcyvVC4A4RozmA=
 github.com/Microsoft/hcsshim v0.8.6 h1:ZfF0+zZeYdzMIVMZHKtDKJvLHj76XCuVae/jNkjj0IA=
@@ -10,12 +12,6 @@ github.com/containerd/continuity v0.0.0-20180216233310-d8fb8589b0e8 h1:ZZOFPzvZO
 github.com/containerd/continuity v0.0.0-20180216233310-d8fb8589b0e8/go.mod h1:GL3xCUCBDV3CZiTSEKksMWbLE66hEyuu9qyDOOqM47Y=
 github.com/containers/buildah v1.8.4 h1:06c+UNeEWMa2wA1Z7muZ0ZqUzE91sDuZJbB0BiZaeYQ=
 github.com/containers/buildah v1.8.4/go.mod h1:1CsiLJvyU+h+wOjnqJJOWuJCVcMxZOr5HN/gHGdzJxY=
-github.com/containers/image v1.5.2-0.20190620105408-93b1deece293 h1:EalCgZ875kDCN2HcOch50q48GKerWGc5eV0BllCvln8=
-github.com/containers/image v1.5.2-0.20190620105408-93b1deece293/go.mod h1:8Vtij257IWSanUQKe1tAeNOm2sRVkSqQTVQ1IlwI3+M=
-github.com/containers/image v1.5.2-0.20190717062552-2178abd5f9b1 h1:RGlzwWSoGBbc5fgGysRrGAPLn8xQwihzRVPVDW5yQlo=
-github.com/containers/image v1.5.2-0.20190717062552-2178abd5f9b1/go.mod h1:8Vtij257IWSanUQKe1tAeNOm2sRVkSqQTVQ1IlwI3+M=
-github.com/containers/image v2.0.0+incompatible h1:FTr6Br7jlIKNCKMjSOMbAxKp2keQ0//jzJaYNTVhauk=
-github.com/containers/image v2.0.0+incompatible/go.mod h1:8Vtij257IWSanUQKe1tAeNOm2sRVkSqQTVQ1IlwI3+M=
 github.com/containers/storage v1.12.10 h1:vw1aiLsZ1LvO09ELMxVBTe35tThRiMftI2cPeH+G5ow=
 github.com/containers/storage v1.12.10/go.mod h1:+RirK6VQAqskQlaTBrOG6ulDvn4si2QjFE1NZCn06MM=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
@@ -36,6 +32,8 @@ github.com/etcd-io/bbolt v1.3.2 h1:RLRQ0TKLX7DlBRXAJHvbmXL17Q3KNnTBtZ9B6Qo+/Y0=
 github.com/etcd-io/bbolt v1.3.2/go.mod h1:ZF2nL25h33cCyBtcyWeZ2/I3HQOfTP+0PIEvHjkjCrw=
 github.com/ghodss/yaml v0.0.0-20150909031657-73d445a93680 h1:ZktWZesgun21uEDrwW7iEV1zPCGQldM2atlJZ3TdvVM=
 github.com/ghodss/yaml v0.0.0-20150909031657-73d445a93680/go.mod h1:4dBDuWmgqj2HViK6kFavaiC9ZROes6MMH2rRYeMEF04=
+github.com/giuseppe/image v0.0.0-20190717145617-e25c2090aca9 h1:6ueBJD2TFrqPco07vc/TlAZ2gOtkWaF2PuCycXZOyvg=
+github.com/giuseppe/image v0.0.0-20190717145617-e25c2090aca9/go.mod h1:t1Xf5SPi6pYsMJfQTMHfTpWgaQkRuy+0HMhAOJOj01E=
 github.com/go-check/check v0.0.0-20180628173108-788fd7840127 h1:0gkP6mzaMqkmpcJYCFOLkIBwI7xFExG03bbkOkCvUPI=
 github.com/go-check/check v0.0.0-20180628173108-788fd7840127/go.mod h1:9ES+weclKsC9YodN5RgxqK/VD9HM9JsCSh7rNhMZE98=
 github.com/gogo/protobuf v0.0.0-20170815085658-fcdc5011193f h1:r/AdTzqktq9nQpFlFePWcp+scVi+oFRajfjRJ3UnETg=
@@ -101,12 +99,8 @@ github.com/urfave/cli v1.20.0 h1:fDqGv3UG/4jbVl/QkFwEdddtEDjh/5Ov6X+0B/3bPaw=
 github.com/urfave/cli v1.20.0/go.mod h1:70zkFmudgCuE/ngEzBv17Jvp/497gISqfk5gWijbERA=
 github.com/vbatts/tar-split v0.10.2 h1:CXd7HEKGkTLjBMinpObcJZU5Hm8EKlor2a1JtX6msXQ=
 github.com/vbatts/tar-split v0.10.2/go.mod h1:LEuURwDEiWjRjwu46yU3KVGuUdVv/dcnpcEPSzR8z6g=
-github.com/vbauerster/mpb v3.3.4+incompatible h1:DDIhnwmgTQIDZo+SWlEr5d6mJBxkOLBwCXPzunhEfJ4=
-github.com/vbauerster/mpb v3.3.4+incompatible/go.mod h1:zAHG26FUhVKETRu+MWqYXcI70POlC6N8up9p1dID7SU=
 github.com/vbauerster/mpb v3.4.0+incompatible h1:mfiiYw87ARaeRW6x5gWwYRUawxaW1tLAD8IceomUCNw=
 github.com/vbauerster/mpb v3.4.0+incompatible/go.mod h1:zAHG26FUhVKETRu+MWqYXcI70POlC6N8up9p1dID7SU=
-github.com/vrothberg/image v0.0.0-20190717060034-cd5ce8239f51 h1:u4Hw4D3PLODtsZJ1FKi7j8bkd+zyJOc28dRSiVTOgyE=
-github.com/vrothberg/image v0.0.0-20190717060034-cd5ce8239f51/go.mod h1:/hIyjuUvIY6X2wGj/fbsA9zwlfAize8B2DLPishEHHg=
 github.com/xeipuuv/gojsonpointer v0.0.0-20180127040702-4e3ac2762d5f h1:J9EGpcZtP0E/raorCMxlFGSTBrsSlaDGf3jU/qvAE2c=
 github.com/xeipuuv/gojsonpointer v0.0.0-20180127040702-4e3ac2762d5f/go.mod h1:N2zxlSyiKSe5eX1tZViRH5QA0qijqEDrYZiPEAiq3wU=
 github.com/xeipuuv/gojsonreference v0.0.0-20180127040603-bd5ef7bd5415 h1:EzJWgHovont7NscjpAxXsDA8S8BMYve8Y5+7cuRE7R0=