init

Dockerfile

@@ -0,0 +1,17 @@
+FROM golang:alpine as builder
+COPY . /go/src/github.com/concourse/registry-image-resource
+ENV CGO_ENABLED 0
+RUN go build -o /assets/in github.com/concourse/registry-image-resource/cmd/in
+RUN go build -o /assets/out github.com/concourse/registry-image-resource/cmd/out
+RUN go build -o /assets/check github.com/concourse/registry-image-resource/cmd/check
+WORKDIR /go/src/github.com/concourse/registry-image-resource
+RUN set -e; for pkg in $(go list ./...); do \
+		go test -o "/tests/$(basename $pkg).test" -c $pkg; \
+	done
+
+FROM alpine:edge AS resource
+RUN apk add --no-cache bash tzdata ca-certificates unzip zip gzip tar
+COPY --from=builder assets/ /opt/resource/
+RUN chmod +x /opt/resource/*
+
+FROM resource

LICENSE.md

@@ -0,0 +1,201 @@
+Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
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+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
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+      including but not limited to software source code, documentation
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+      "Work" shall mean the work of authorship, whether in Source or
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+      (an example is provided in the Appendix below).
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+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
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+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "{}"
+      replaced with your own identifying information. (Don't include
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+      file or class name and description of purpose be included on the
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+
+   Copyright {yyyy} {name of copyright owner}
+
+   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.

NOTICE.md

@@ -0,0 +1,12 @@
+Copyright 2018 Alex Suraci, Chris Brown, and Pivotal Software, Inc.
+
+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.

cmd/check/main.go

@@ -0,0 +1,99 @@
+package main
+
+import (
+	"encoding/json"
+	"os"
+
+	resource "github.com/concourse/registry-image-resource"
+	"github.com/google/go-containerregistry/pkg/name"
+	"github.com/google/go-containerregistry/pkg/v1/remote"
+	"github.com/sirupsen/logrus"
+)
+
+type CheckRequest struct {
+	Source  resource.Source   `json:"source"`
+	Version *resource.Version `json:"version"`
+}
+
+type CheckResponse []resource.Version
+
+func main() {
+	logrus.SetOutput(os.Stderr)
+
+	var req CheckRequest
+	err := json.NewDecoder(os.Stdin).Decode(&req)
+	if err != nil {
+		logrus.Errorf("invalid payload: %s", err)
+		os.Exit(1)
+		return
+	}
+
+	ref := req.Source.Repository + ":" + req.Source.Tag
+
+	n, err := name.ParseReference(ref, name.WeakValidation)
+	if err != nil {
+		logrus.Errorf("could not resolve repository/tag reference: %s", err)
+		os.Exit(1)
+		return
+	}
+
+	image, err := remote.Image(n)
+	if err != nil {
+		logrus.Errorf("failed to get remote image: %s", err)
+		os.Exit(1)
+		return
+	}
+
+	digest, err := image.Digest()
+	if err != nil {
+		logrus.Errorf("failed get image digest: %s", err)
+		os.Exit(1)
+		return
+	}
+
+	response := CheckResponse{}
+	if req.Version != nil && req.Version.Digest != digest.String() {
+		digestRef, err := name.ParseReference(req.Source.Repository+"@"+req.Version.Digest, name.WeakValidation)
+		if err != nil {
+			logrus.Errorf("could not resolve repository/digest reference: %s", err)
+			os.Exit(1)
+			return
+		}
+
+		digestImage, err := remote.Image(digestRef)
+		if err != nil {
+			logrus.Errorf("failed to get remote image: %s", err)
+			os.Exit(1)
+			return
+		}
+
+		var missingDigest bool
+		_, err = digestImage.Digest()
+		if err != nil {
+			if rErr, ok := err.(*remote.Error); ok {
+				for _, e := range rErr.Errors {
+					if e.Code == remote.ManifestUnknownErrorCode {
+						missingDigest = true
+						break
+					}
+				}
+			}
+
+			if !missingDigest {
+				logrus.Errorf("failed to get cursor image digest: %s", err)
+				os.Exit(1)
+				return
+			}
+		}
+
+		if !missingDigest {
+			response = append(response, *req.Version)
+		}
+	}
+
+	response = append(response, resource.Version{
+		Digest: digest.String(),
+	})
+
+	json.NewEncoder(os.Stdout).Encode(response)
+}

cmd/in/main.go

@@ -0,0 +1,98 @@
+package main
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+
+	resource "github.com/concourse/registry-image-resource"
+	"github.com/google/go-containerregistry/pkg/name"
+	"github.com/google/go-containerregistry/pkg/v1/remote"
+	"github.com/sirupsen/logrus"
+)
+
+type InRequest struct {
+	Source  resource.Source  `json:"source"`
+	Version resource.Version `json:"version"`
+}
+
+type InResponse struct {
+	Version  resource.Version `json:"version"`
+	Metadata []MetadataField  `json:"metadata"`
+}
+
+type ImageMetadata struct {
+	Env  []string `json:"env"`
+	User string   `json:"user"`
+}
+
+type MetadataField struct {
+	Name  string `json:"name"`
+	Value string `json:"value"`
+}
+
+func main() {
+	logrus.SetOutput(os.Stderr)
+
+	var req InRequest
+	err := json.NewDecoder(os.Stdin).Decode(&req)
+	if err != nil {
+		logrus.Errorf("invalid payload: %s", err)
+		os.Exit(1)
+		return
+	}
+
+	dest := os.Args[1]
+
+	ref := req.Source.Repository + ":" + req.Source.Tag
+
+	n, err := name.ParseReference(ref, name.WeakValidation)
+	if err != nil {
+		logrus.Errorf("failed to resolve name: %s", err)
+		os.Exit(1)
+		return
+	}
+
+	image, err := remote.Image(n)
+	if err != nil {
+		logrus.Errorf("Failed to locate remote image: %s", err)
+		os.Exit(1)
+		return
+	}
+
+	err = unpackImage(filepath.Join(dest, "rootfs"), image)
+	if err != nil {
+		logrus.Errorf("Failed to extract image: %s", err)
+		os.Exit(1)
+		return
+	}
+
+	meta, err := os.Create(filepath.Join(dest, "metadata.json"))
+	if err != nil {
+		logrus.Errorf("Failed to create image metadata: %s", err)
+		os.Exit(1)
+		return
+	}
+
+	cfg, err := image.ConfigFile()
+	if err != nil {
+		logrus.Errorf("Failed to inspect image config: %s", err)
+		os.Exit(1)
+		return
+	}
+
+	err = json.NewEncoder(meta).Encode(ImageMetadata{
+		Env:  cfg.ContainerConfig.Env,
+		User: cfg.ContainerConfig.User,
+	})
+	if err != nil {
+		logrus.Errorf("Failed to write image metadata: %s", err)
+		os.Exit(1)
+		return
+	}
+
+	json.NewEncoder(os.Stdout).Encode(InResponse{
+		Version:  req.Version,
+		Metadata: []MetadataField{},
+	})
+}

cmd/in/unpack.go

@@ -0,0 +1,91 @@
+package main
+
+import (
+	"archive/tar"
+	"io"
+	"path/filepath"
+	"strings"
+
+	"github.com/concourse/go-archive/tarfs"
+	"github.com/google/go-containerregistry/pkg/v1"
+)
+
+const whiteoutPrefix = ".wh."
+
+func unpackImage(dest string, img v1.Image) error {
+	layers, err := img.Layers()
+	if err != nil {
+		return err
+	}
+
+	written := map[string]struct{}{}
+	removed := map[string]struct{}{}
+
+	// iterate over layers in reverse order; no need to write things files that
+	// are modified by later layers anyway
+	for i := len(layers) - 1; i >= 0; i-- {
+		layer := layers[i]
+
+		r, err := layer.Uncompressed()
+		if err != nil {
+			return err
+		}
+
+		tr := tar.NewReader(r)
+
+		for {
+			hdr, err := tr.Next()
+			if err == io.EOF {
+				break
+			}
+
+			if err != nil {
+				return err
+			}
+
+			path := filepath.Join(dest, filepath.Clean(hdr.Name))
+			base := filepath.Base(path)
+			dir := filepath.Dir(path)
+
+			if strings.HasPrefix(base, whiteoutPrefix) {
+				// layer has marked a file as deleted
+				name := strings.TrimPrefix(base, whiteoutPrefix)
+				removed[filepath.Join(dir, name)] = struct{}{}
+				continue
+			}
+
+			if pathIsRemoved(path, removed) {
+				// path has been removed by lower layer
+				continue
+			}
+
+			if _, ok := written[path]; ok {
+				// path has already been written by lower layer
+				continue
+			}
+
+			written[path] = struct{}{}
+
+			if err := tarfs.ExtractEntry(hdr, dest, tr, true); err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
+func pathIsRemoved(path string, removed map[string]struct{}) bool {
+	if _, ok := removed[path]; ok {
+		return true
+	}
+
+	// check if parent dir has been removed
+	for wd := range removed {
+		if strings.HasPrefix(path, wd) {
+			return true
+		}
+	}
+
+	return false
+}

cmd/out/main.go

@@ -0,0 +1,13 @@
+package main
+
+import (
+	"os"
+
+	"github.com/sirupsen/logrus"
+)
+
+func main() {
+	logrus.SetOutput(os.Stderr)
+	logrus.Error("not implemented")
+	os.Exit(1)
+}

types.go

@@ -0,0 +1,10 @@
+package resource
+
+type Source struct {
+	Repository string `json:"repository"`
+	Tag        string `json:"tag"`
+}
+
+type Version struct {
+	Digest string `json:"digest"`
+}