image: Refactor to use cas/ref engines instead of walkers

.gitignore

@@ -1,3 +1,6 @@
+/oci-cas
 /oci-create-runtime-bundle
-/oci-unpack
+/oci-image-init
 /oci-image-validate
+/oci-refs
+/oci-unpack

.tool/lint

@@ -14,6 +14,12 @@ for d in $(find . -type d -not -iwholename '*.git*' -a -not -iname '.tool' -a -n
 		--exclude='error return value not checked.*(Close|Log|Print).*\(errcheck\)$' \
 		--exclude='.*_test\.go:.*error return value not checked.*\(errcheck\)$' \
 		--exclude='duplicate of.*_test.go.*\(dupl\)$' \
+		--exclude='^cmd/oci-cas/delete.go:.* duplicate of .* \(dupl\)$' \
+		--exclude='^cmd/oci-cas/get.go:.* duplicate of .* \(dupl\)$' \
+		--exclude='^cmd/oci-refs/delete.go:.* duplicate of .* \(dupl\)$' \
+		--exclude='^cmd/oci-refs/get.go:.* duplicate of .* \(dupl\)$' \
+		--exclude='^image/cas/layout/dir.go:.* duplicate of .* \(dupl\)$' \
+		--exclude='^image/refs/layout/dir.go:.* duplicate of .* \(dupl\)$' \
 		--exclude='schema/fs.go' \
 		--exclude='duplicate of.*main.go.*\(dupl\)$' \
 		--disable=aligncheck \

Makefile

@@ -5,8 +5,11 @@ COMMIT=$(shell git rev-parse HEAD 2> /dev/null || true)
 
 EPOCH_TEST_COMMIT ?= v0.2.0
 TOOLS := \
+	oci-cas \
 	oci-create-runtime-bundle \
+	oci-image-init \
 	oci-image-validate \
+	oci-refs \
 	oci-unpack
 
 default: help

cmd/oci-cas/delete.go

@@ -0,0 +1,72 @@
+// Copyright 2016 The Linux Foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/opencontainers/image-tools/image/cas/layout"
+	"github.com/spf13/cobra"
+	"golang.org/x/net/context"
+)
+
+type deleteCmd struct {
+	path   string
+	digest string
+}
+
+func newDeleteCmd() *cobra.Command {
+	state := &deleteCmd{}
+
+	return &cobra.Command{
+		Use:   "delete PATH DIGEST",
+		Short: "Remove a blob from from the store",
+		Run:   state.Run,
+	}
+}
+
+func (state *deleteCmd) Run(cmd *cobra.Command, args []string) {
+	if len(args) != 2 {
+		fmt.Fprintln(os.Stderr, "both PATH and DIGEST must be provided")
+		if err := cmd.Usage(); err != nil {
+			fmt.Fprintln(os.Stderr, err)
+		}
+		os.Exit(1)
+	}
+
+	state.path = args[0]
+	state.digest = args[1]
+
+	err := state.run()
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+
+	os.Exit(0)
+}
+
+func (state *deleteCmd) run() (err error) {
+	ctx := context.Background()
+
+	engine, err := layout.NewEngine(ctx, state.path)
+	if err != nil {
+		return err
+	}
+	defer engine.Close()
+
+	return engine.Delete(ctx, state.digest)
+}

cmd/oci-cas/get.go

@@ -0,0 +1,93 @@
+// Copyright 2016 The Linux Foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"github.com/opencontainers/image-tools/image/cas/layout"
+	"github.com/spf13/cobra"
+	"golang.org/x/net/context"
+)
+
+type getCmd struct {
+	path   string
+	digest string
+}
+
+func newGetCmd() *cobra.Command {
+	state := &getCmd{}
+
+	return &cobra.Command{
+		Use:   "get PATH DIGEST",
+		Short: "Retrieve a blob from the store",
+		Long:  "Retrieve a blob from the store and write it to stdout.",
+		Run:   state.Run,
+	}
+}
+
+func (state *getCmd) Run(cmd *cobra.Command, args []string) {
+	if len(args) != 2 {
+		fmt.Fprintln(os.Stderr, "both PATH and DIGEST must be provided")
+		if err := cmd.Usage(); err != nil {
+			fmt.Fprintln(os.Stderr, err)
+		}
+		os.Exit(1)
+	}
+
+	state.path = args[0]
+	state.digest = args[1]
+
+	err := state.run()
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+
+	os.Exit(0)
+}
+
+func (state *getCmd) run() (err error) {
+	ctx := context.Background()
+
+	engine, err := layout.NewEngine(ctx, state.path)
+	if err != nil {
+		return err
+	}
+	defer engine.Close()
+
+	reader, err := engine.Get(ctx, state.digest)
+	if err != nil {
+		return err
+	}
+	defer reader.Close()
+
+	bytes, err := ioutil.ReadAll(reader)
+	if err != nil {
+		return err
+	}
+
+	n, err := os.Stdout.Write(bytes)
+	if err != nil {
+		return err
+	}
+	if n < len(bytes) {
+		return fmt.Errorf("wrote %d of %d bytes", n, len(bytes))
+	}
+
+	return nil
+}

cmd/oci-cas/main.go

@@ -0,0 +1,39 @@
+// Copyright 2016 The Linux Foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/spf13/cobra"
+)
+
+func main() {
+	cmd := &cobra.Command{
+		Use:   "oci-cas",
+		Short: "Content-addressable storage manipulation",
+	}
+
+	cmd.AddCommand(newGetCmd())
+	cmd.AddCommand(newPutCmd())
+	cmd.AddCommand(newDeleteCmd())
+
+	err := cmd.Execute()
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}

cmd/oci-cas/oci-cas-delete.1.md

@@ -0,0 +1,27 @@
+% OCI(1) OCI-IMAGE-TOOL User Manuals
+% OCI Community
+% SEPTEMBER 2016
+# NAME
+
+oci-cas-get \- Remove a blob from the store
+
+# SYNOPSIS
+
+**oci-cas delete** [OPTIONS] PATH DIGEST
+
+# DESCRIPTION
+
+`oci-cas delete` removes the blob referenced by `DIGEST` from the store at `PATH`.
+
+# OPTIONS
+
+**--help**
+  Print usage statement
+
+# SEE ALSO
+
+**oci-cas**(1), **oci-cas-get**(1), **oci-cas-put**(1)
+
+# HISTORY
+
+September 2016, Originally compiled by W. Trevor King (wking at tremily dot us)

cmd/oci-cas/oci-cas-get.1.md

@@ -0,0 +1,27 @@
+% OCI(1) OCI-IMAGE-TOOL User Manuals
+% OCI Community
+% AUGUST 2016
+# NAME
+
+oci-cas-get \- Retrieve a blob from the store
+
+# SYNOPSIS
+
+**oci-cas get** [OPTIONS] PATH DIGEST
+
+# DESCRIPTION
+
+`oci-cas get` retrieves a blob referenced by `DIGEST` from the store at `PATH` and writes it to standard output.
+
+# OPTIONS
+
+**--help**
+  Print usage statement
+
+# SEE ALSO
+
+**oci-cas**(1), **oci-cas-put**(1), **oci-cas-delete**(1)
+
+# HISTORY
+
+August 2016, Originally compiled by W. Trevor King (wking at tremily dot us)

cmd/oci-cas/oci-cas-put.1.md

@@ -0,0 +1,27 @@
+% OCI(1) OCI-IMAGE-TOOL User Manuals
+% OCI Community
+% AUGUST 2016
+# NAME
+
+oci-cas-put \- Write a blob to the store
+
+# SYNOPSIS
+
+**oci-cas put** [OPTIONS] PATH
+
+# DESCRIPTION
+
+`oci-cas put` reads a blob from stdin, writes it to the store at `PATH`, and prints the digest to standard output.
+
+# OPTIONS
+
+**--help**
+  Print usage statement
+
+# SEE ALSO
+
+**oci-cas**(1), **oci-cas-get**(1), **oci-cas-delete**(1)
+
+# HISTORY
+
+August 2016, Originally compiled by W. Trevor King (wking at tremily dot us)

cmd/oci-cas/oci-cas.1.md

@@ -0,0 +1,52 @@
+% OCI(1) OCI-User Manuals
+% OCI Community
+% AUGUST 2016
+# NAME
+
+oci-cas \- Content-addressable storage manipulation
+
+# SYNOPSIS
+
+**oci-cas** [command]
+
+# DESCRIPTION
+
+`oci-cas` manipulates content-addressable storage.
+
+# OPTIONS
+
+**--help**
+  Print usage statement
+
+# COMMANDS
+
+**get**
+  Retrieve a blob from the store.
+  See **oci-cas-get**(1) for full documentation on the **get** command.
+
+**put**
+  Write a blob to the store.
+  See **oci-cas-put**(1) for full documentation on the **put** command.
+
+**delete**
+  Remove a blob from the store.
+  See **oci-cas-delete**(1) for full documentation on the **delete** command.
+
+# EXAMPLES
+
+```
+$ oci-image-init image-layout image
+$ echo hello | oci-cas put image
+sha256:5891b5b522d5df086d0ff0b110fbd9d21bb4fc7163af34d08286a2e846f6be03
+$ oci-cas get image sha256:5891b5b522d5df086d0ff0b110fbd9d21bb4fc7163af34d08286a2e846f6be03
+hello
+$ oci-cas delete image sha256:5891b5b522d5df086d0ff0b110fbd9d21bb4fc7163af34d08286a2e846f6be03
+```
+
+# SEE ALSO
+
+**oci-image-tools**(7), **oci-cas-get**(1), **oci-cas-put**(1), **oci-cas-delete**(1), **oci-image-init**(1)
+
+# HISTORY
+
+August 2016, Originally compiled by W. Trevor King (wking at tremily dot us)