Implementasi docker pull dan docker push commands tanpa klien docker melalui permintaan HTTP

Kita dulu punya 2 kantong rumput, 75 tablet mescaline unix environment, docker repository dan tugas untuk mengimplementasikan docker pull dan docker push commands tanpa klien docker.

UPD:
Pertanyaan: Untuk apa semua ini?
Jawab: Memuat pengujian produk (BUKAN dengan cara bash, skrip disediakan untuk tujuan pendidikan). Diputuskan untuk tidak menggunakan klien buruh pelabuhan untuk mengurangi lapisan tambahan (dalam batas yang wajar) dan, karenanya, meniru beban yang lebih tinggi. Akibatnya, semua penundaan sistem klien buruh pelabuhan dihapus. Menerima beban yang relatif bersih langsung pada produk

Pertama, mari kita lihat apa yang dilakukan tim-tim ini.

Jadi untuk apa docker pull digunakan? Menurut dokumentasi :

"Tarik gambar atau repositori dari registri".

Di sana kami menemukan tautan untuk memahami gambar, wadah, dan driver penyimpanan .

docker image layers, , . registry API.

:

"An “image” is a combination of a JSON manifest and individual layer files. The process of pulling an > image centers around retrieving these two components."

“Pulling an Image Manifest”.

, . : GET /v2/{name}/manifests/{reference}

"The name and reference parameter identify the image and are required. The reference may include a tag or digest."

, :

curl -s -X GET "http://localhost:8081/link/to/docker/registry/v2/centos-11-10/manifests/1.1.1" -H "header_if_needed"

json , . , : "GET /v2/{name}/blobs/{digest}"

“Access to a layer will be gated by the name of the repository but is identified uniquely in the registry by digest.”

digest , .

curl -s -X GET "http://localhost:8081/link/to/docker/registry/v2/centos-11-10/blobs/sha256:f972d139738dfcd1519fd2461815651336ee25a8b54c358834c50af094bb262f" -H "header_if_needed" --output firstLayer

.

file firstLayer

.. tar , .

#!/bin/bash -eu

downloadDir=$1
# url as http://localhost:8081/link/to/docker/registry
url=$2
imageName=$3
tag=$4

# array of layers
layers=($(curl -s -X GET "$url/v2/$imageName/manifests/$tag" | grep -oP '(?<=blobSum" : ").+(?=")'))

# download each layer from array
for layer in "${layers[@]}"; do
    echo "Downloading ${layer}"
    curl -v -X GET "$url/v2/$imageName/blobs/$layer" --output "$downloadDir/$layer.tar"
done

# find all layers, untar them and remove source .tar files
cd "$downloadDir" && find . -name "sha256:*" -exec tar xvf {} \;
rm sha256:*.tar
exit 0

./script.sh dirName “http://localhost:8081/link/to/docker/registry” myAwesomeImage 1.0

2 — docker push

.

. , . .

:

• — "POST /v2/{repoName}/blobs/uploads/"
• ( , .. ) — "PUT /v2/{repoName}/blobs/uploads/{uuid}?digest={digest}
  Content-Length: {size of layer}
  Content-Type: application/octet-stream
  Layer Binary Data".
• — "PUT /v2/{repoName}/manifests/{reference}".

, . (chunked) PATCH :

"PATCH /v2/{repoName}/blobs/uploads/{uuid}
Content-Length: {size of chunk}
Content-Type: application/octet-stream
{Layer Chunk Binary Data}".

, .. 202 4.

:

• 
  2 3 , .

. archlinux:latest

docker pull archlinux

docker save c24fe13d37b9 -o savedArch

tar xvf savedArch

. ,

cat manifest.json | json_pp

. , .

, .

config . 2 ( ), mediaType :

echo ‘{
   "schemaVersion": 2,
   "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
   "config": {
      "mediaType": "application/vnd.docker.container.image.v1+json",
      "size": config_size,
      "digest": "config_hash"
   },
   "layers": [
      ’ > manifest.json

. json :

{
         "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip",
         "size": ${layersSizes[$i]},
         "digest": \"sha256:${layersNames[$i]}\"
      },

.

sed -i "s/config_size/$configSize/g; s/config_hash/$configName/g" $manifestFile

Sekarang Anda dapat memulai proses boot dan menyelamatkan diri Anda sendiri, yang harus disertai dengan semua permintaan berikutnya.

Script lengkapnya terlihat seperti ini:

#!/bin/bash -eux

imageDir=$1
# url as http://localhost:8081/link/to/docker/registry
url=$2
repoName=$3
tag=$4
manifestFile=$(readlink -f ${imageDir}/manifestCopy)
configFile=$(readlink -f $(find $imageDir -name "*.json" ! -name "manifest.json"))

# calc layers sha 256 sum, rename them accordingly, and add info about each to manifest file
function prepareLayersForUpload() {
  info_file=$imageDir/info
  # lets calculate layers sha256 and use it as layers names further
  layersNames=($(find $imageDir -name "layer.tar" -exec shasum -a 256 {} \; | cut -d" " -f1))

  # rename layers according to shasums. !!!Set required amount of fields for cut command!!!
  # this part definitely can be done easier but i didn't found another way, sry
  find $imageDir -name "layer.tar" -exec bash -c 'mv {} "$(echo {} | cut -d"/" -f1,2)/$(shasum -a 256 {} | cut -d" " -f1)"' \;

  layersSizes=($(find $imageDir -name "*.tar" -exec ls -l {} \; | awk '{print $5}'))

  for i in "${!layersNames[@]}"; do
    echo "{
         "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip",
         "size": ${layersSizes[$i]},
         "digest": \"sha256:${layersNames[$i]}\"
      }," >> $manifestFile
  done
  # remove last ','
  truncate -s-2 $manifestFile
  # add closing brakets to keep json consistent
  printf "\n\t]\n}" >> $manifestFile
}

# calc config sha 256 sum and add info about it to manifest
function setConfigProps() {
  configSize=$(ls -l $configFile | awk '{print $5}')
  configName=$(basename $configFile | cut -d"." -f1)

  sed -i "s/config_size/$configSize/g; s/config_hash/$configName/g" $manifestFile
}

#prepare manifest file
prepareLayersForUpload
setConfigProps
cat $manifestFile

# initiate upload and get uuid
uuid=$(curl -s -X POST -I "$url/v2/$repoName/blobs/uploads/" | grep -oP "(?<=Docker-Upload-Uuid: ).+")

# patch layers
# in data-binary we're getting absolute path to layer file
for l in "${!layersNames[@]}"; do
  pathToLayer=$(find $imageDir -name ${layersNames[$l]} -exec readlink -f {} \;)
    curl -v -X PATCH "$url/v2/$repoName/blobs/uploads/$uuid" \
  -H "Content-Length: ${layersSizes[$i]}" \
  -H "Content-Type: application/octet-stream" \
  --data-binary "@$pathToLayer"

# put layer
  curl -v -X PUT "$url/v2/$repoName/blobs/uploads/$uuid?digest=sha256:${layersNames[$i]}" \
  -H 'Content-Type: application/octet-stream' \
  -H "Content-Length: ${layersSizes[$i]}" \
  --data-binary "@$pathToLayer"
done

# patch and put config after all layers
curl -v -X PATCH "$url/v2/$repoName/blobs/uploads/$uuid" \
  -H "Content-Length: $configSize" \
  -H "Content-Type: application/octet-stream" \
  --data-binary "@$configFile"

  curl -v -X PUT "$url/v2/$repoName/blobs/uploads/$uuid?digest=sha256:$configName" \
  -H 'Content-Type: application/octet-stream' \
  -H "Content-Length: $configSize" \
  --data-binary "@$configFile"

# put manifest
curl -v -X PUT "$url/v2/$repoName/manifests/$tag" \
  -H 'Content-Type: application/vnd.docker.distribution.manifest.v2+json' \
  --data-binary "@$manifestFile"

exit 0

kita dapat menggunakan skrip yang sudah jadi:

./uploadImage.sh "~/path/to/saved/image" "http://localhost:8081/link/to/docker/registry" myRepoName 1.0

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