feat: docker image

Author: jmattheis

.gitignore

@@ -5,3 +5,5 @@ privkey.pub
 public
 build
 assets/jmattheis-resume.pdf
+docker/registry/busybox/
+gemini_cache/

README.md

@@ -17,6 +17,7 @@ curl     tftp://jmattheis.de
 dict -h         jmattheis.de -I
 dig            @jmattheis.de +tcp +short
 docker -H       jmattheis.de inspect -f '{{.Value}}' start
+docker run --rm jmattheis.de/start
 finger          jmattheis.de
 gemget gemini://jmattheis.de/ -o-
 netcat          jmattheis.de 23

assets/index.html

@@ -114,6 +114,7 @@ <h2>Hacky</h2>
 $ dict -h         jmattheis.de -I
 $ dig            @jmattheis.de +tcp +short
 $ docker -H       jmattheis.de inspect -f '{{`{{.Value}}`}}' start
+$ docker run --rm jmattheis.de/start
 $ finger          jmattheis.de
 $ gemget gemini://jmattheis.de/ -o-
 $ netcat          jmattheis.de 23

content/text.go

@@ -36,6 +36,7 @@ Try one of the following commands in your terminal:
   dict -h         jmattheis.de -I
   dig            @jmattheis.de +tcp +short
   docker -H       jmattheis.de inspect -f '{{.Value}}' start
+  docker run --rm jmattheis.de/start
   finger          jmattheis.de
   gemget gemini://jmattheis.de/ -o-
   netcat          jmattheis.de 23

docker/registry/builder.go

@@ -0,0 +1,76 @@
+package dockerregistry
+
+import (
+	"encoding/json"
+
+	"github.com/distribution/distribution/v3"
+	"github.com/distribution/distribution/v3/manifest/ocischema"
+	"github.com/opencontainers/go-digest"
+	v1 "github.com/opencontainers/image-spec/specs-go/v1"
+)
+
+type Entry struct {
+	Digest    digest.Digest
+	MediaType string
+	Content   []byte
+}
+
+func DockerStdout(content string) map[string]Entry {
+	var bManifests ocischema.DeserializedImageIndex
+	check(bManifests.UnmarshalJSON(read("manifest.json")))
+
+	store := map[string]Entry{}
+
+	var newManifestDescriptions []distribution.Descriptor
+	for _, maniDesc := range bManifests.Manifests {
+		m := ocischema.Manifest{}
+		check(json.Unmarshal(read(maniDesc.Digest.Encoded()+".manifest.json"), &m))
+		m.Annotations = nil
+
+		cfg := v1.Image{}
+		check(json.Unmarshal(read(m.Config.Digest.Encoded()), &cfg))
+		cfg.Config.Cmd = []string{"echo", content}
+		m.Config.Digest, m.Config.Size = registerJson(store, "application/octet-stream", cfg)
+
+		for _, layer := range m.Layers {
+			registerRaw(store, "application/octet-stream", read(layer.Digest.Encoded()))
+		}
+
+		maniDesc.Digest, maniDesc.Size = registerJson(store, v1.MediaTypeImageManifest, m)
+
+		newManifestDescriptions = append(newManifestDescriptions, maniDesc)
+	}
+	index, err := ocischema.FromDescriptors(newManifestDescriptions, nil)
+	check(err)
+
+	digest, _ := registerJson(store, v1.MediaTypeImageIndex, index)
+
+	store["latest"] = Entry{
+		Digest:    digest,
+		MediaType: v1.MediaTypeImageIndex,
+		Content:   store[digest.String()].Content,
+	}
+	return store
+}
+
+func registerJson(store map[string]Entry, mediaType string, value any) (digest.Digest, int64) {
+	b, err := json.Marshal(value)
+	check(err)
+	return registerRaw(store, mediaType, b)
+}
+
+func registerRaw(store map[string]Entry, mediaType string, b []byte) (digest.Digest, int64) {
+	d := digest.FromBytes(b)
+	store[d.String()] = Entry{
+		Digest:    d,
+		MediaType: mediaType,
+		Content:   b,
+	}
+	return d, int64(len(b))
+}
+
+func check(err error) {
+	if err != nil {
+		panic(err)
+	}
+}

docker/registry/embed.go

@@ -0,0 +1,15 @@
+package dockerregistry
+
+import (
+	"embed"
+	"path"
+)
+
+//go:embed busybox/*
+var images embed.FS
+
+func read(s string) []byte {
+	b, err := images.ReadFile(path.Join("busybox", s))
+	check(err)
+	return b
+}

docker/registry/generate.go

@@ -0,0 +1,4 @@
+//go:generate rm -rf ./busybox
+//go:generate skopeo copy --multi-arch=all docker://index.docker.io/library/busybox:latest dir:./busybox
+
+package dockerregistry

docker/registry/http.go

@@ -0,0 +1,72 @@
+package dockerregistry
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"regexp"
+	"strings"
+
+	lru "github.com/hashicorp/golang-lru/v2"
+	"github.com/jmattheis/website/content"
+)
+
+var pattern = regexp.MustCompile(`\/v2\/(.+)\/(blobs|manifests)\/([a-z0-9:]+)`)
+
+func Handler() http.HandlerFunc {
+	tty := content.SingleText{
+		Split:         "/",
+		CommandPrefix: "docker run --rm jmattheis.de/",
+	}
+
+	successCache, err := lru.New[string, map[string]Entry](50)
+	check(err)
+	errorCache, err := lru.New[string, map[string]Entry](20)
+	check(err)
+
+	return func(w http.ResponseWriter, r *http.Request) {
+		matches := pattern.FindStringSubmatch(r.URL.Path)
+
+		if matches == nil {
+			io.WriteString(w, "unknown url")
+			w.WriteHeader(404)
+			return
+		}
+
+		cmd, t, hash := matches[1], matches[2], matches[3]
+
+		content := tty.Get(cmd)
+
+		cache := successCache
+		if strings.HasPrefix(content, "error") {
+			cache = errorCache
+		}
+
+		store, ok := cache.Get(cmd)
+		if !ok {
+			store = DockerStdout(content)
+			cache.Add(cmd, store)
+		}
+
+		entry, ok := store[hash]
+		if !ok {
+			if strings.HasPrefix(hash, "sha256:") {
+				w.WriteHeader(404)
+				io.WriteString(w, "unknown hash")
+				return
+			}
+			entry, _ = store["latest"]
+		}
+
+		w.Header().Add("content-type", entry.MediaType)
+		w.Header().Add("content-length", fmt.Sprint(len(entry.Content)))
+		w.Header().Add("etag", `"`+entry.Digest.String()+`"`)
+		if t == "manifests" {
+			w.Header().Add("Docker-Content-Digest", entry.Digest.String())
+		}
+		w.WriteHeader(200)
+		if r.Method != "HEAD" {
+			w.Write(entry.Content)
+		}
+	}
+}

docker/docker.go docker/socket/socket.go

@@ -1,4 +1,4 @@
-package docker
+package socket
 
 import (
 	"encoding/json"

go.mod

@@ -7,40 +7,36 @@ require (
 	git.sr.ht/~adnano/go-gemini v0.2.4
 	github.com/DevelHell/popgun v0.0.0-20170926125504-2c5552e4bf74
 	github.com/NYTimes/gziphandler v1.1.1
+	github.com/distribution/distribution/v3 v3.0.0-alpha.1
 	github.com/emersion/go-imap v1.2.1
 	github.com/emersion/go-message v0.18.0
 	github.com/fclairamb/ftpserver v0.0.0-20200221221851-84e5d668e655
 	github.com/gernest/front v0.0.0-20210301115436-8a0b0a782d0a
 	github.com/gliderlabs/ssh v0.3.6
-	github.com/gobuffalo/packr/v2 v2.8.3
 	github.com/gomarkdown/markdown v0.0.0-20231222211730-1d6d20845b47
 	github.com/gorilla/feeds v1.1.2
 	github.com/gorilla/websocket v1.5.1
 	github.com/grokify/html-strip-tags-go v0.1.0
+	github.com/hashicorp/golang-lru/v2 v2.0.7
 	github.com/miekg/dns v1.1.58
+	github.com/opencontainers/go-digest v1.0.0
+	github.com/opencontainers/image-spec v1.0.2
+	github.com/pin/tftp/v3 v3.1.0
 	github.com/rs/zerolog v1.32.0
 	golang.org/x/crypto v0.21.0
 )
 
 require (
 	github.com/anmitsu/go-shlex v0.0.0-20200514113438-38f4b401e2be // indirect
+	github.com/distribution/reference v0.5.0 // indirect
 	github.com/emersion/go-sasl v0.0.0-20200509203442-7bfe0ed36a21 // indirect
 	github.com/emersion/go-textwrapper v0.0.0-20200911093747-65d896831594 // indirect
 	github.com/go-kit/kit v0.10.0 // indirect
 	github.com/go-logfmt/logfmt v0.5.0 // indirect
-	github.com/gobuffalo/logger v1.0.6 // indirect
-	github.com/gobuffalo/packd v1.0.1 // indirect
-	github.com/karrick/godirwalk v1.16.1 // indirect
-	github.com/markbates/errx v1.1.0 // indirect
-	github.com/markbates/oncer v1.0.0 // indirect
-	github.com/markbates/safe v1.0.1 // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.19 // indirect
 	github.com/petermattis/goid v0.0.0-20180202154549-b0b1615b78e5 // indirect
-	github.com/pin/tftp/v3 v3.1.0 // indirect
 	github.com/sasha-s/go-deadlock v0.3.1 // indirect
-	github.com/sirupsen/logrus v1.8.1 // indirect
-	github.com/stretchr/testify v1.8.1 // indirect
 	golang.org/x/mod v0.14.0 // indirect
 	golang.org/x/net v0.21.0 // indirect
 	golang.org/x/sys v0.18.0 // indirect