6716bf018c
Cleans up a whole bunch of things I wanted to get out of the door right away: * depot internal references to //third_party/nixery have been replaced with //tools/nixery * cleaned up files from Github * fixed SPDX & Copyright headers * code formatting and inclusion in //tools/depotfmt checks Change-Id: Iea79f0fdf3aa04f71741d4f4032f88605ae415bb Reviewed-on: https://cl.tvl.fyi/c/depot/+/5486 Tested-by: BuildkiteCI Reviewed-by: tazjin <tazjin@tvl.su> Autosubmit: tazjin <tazjin@tvl.su>
135 lines
3.4 KiB
Go
135 lines
3.4 KiB
Go
// Copyright 2022 The TVL Contributors
|
|
// SPDX-License-Identifier: Apache-2.0
|
|
|
|
// Package image implements logic for creating the image metadata
|
|
// (such as the image manifest and configuration).
|
|
package manifest
|
|
|
|
import (
|
|
"crypto/sha256"
|
|
"encoding/json"
|
|
"fmt"
|
|
"sort"
|
|
)
|
|
|
|
const (
|
|
// manifest constants
|
|
schemaVersion = 2
|
|
|
|
// media types
|
|
ManifestType = "application/vnd.docker.distribution.manifest.v2+json"
|
|
LayerType = "application/vnd.docker.image.rootfs.diff.tar.gzip"
|
|
configType = "application/vnd.docker.container.image.v1+json"
|
|
|
|
// image config constants
|
|
os = "linux"
|
|
fsType = "layers"
|
|
)
|
|
|
|
type Entry struct {
|
|
MediaType string `json:"mediaType,omitempty"`
|
|
Size int64 `json:"size"`
|
|
Digest string `json:"digest"`
|
|
|
|
// These fields are internal to Nixery and not part of the
|
|
// serialised entry.
|
|
MergeRating uint64 `json:"-"`
|
|
TarHash string `json:",omitempty"`
|
|
}
|
|
|
|
type manifest struct {
|
|
SchemaVersion int `json:"schemaVersion"`
|
|
MediaType string `json:"mediaType"`
|
|
Config Entry `json:"config"`
|
|
Layers []Entry `json:"layers"`
|
|
}
|
|
|
|
type imageConfig struct {
|
|
Architecture string `json:"architecture"`
|
|
OS string `json:"os"`
|
|
|
|
RootFS struct {
|
|
FSType string `json:"type"`
|
|
DiffIDs []string `json:"diff_ids"`
|
|
} `json:"rootfs"`
|
|
|
|
Config struct {
|
|
Cmd []string `json:"cmd,omitempty"`
|
|
Env []string `json:"env,omitempty"`
|
|
} `json:"config"`
|
|
}
|
|
|
|
// ConfigLayer represents the configuration layer to be included in
|
|
// the manifest, containing its JSON-serialised content and SHA256
|
|
// hash.
|
|
type ConfigLayer struct {
|
|
Config []byte
|
|
SHA256 string
|
|
}
|
|
|
|
// imageConfig creates an image configuration with the values set to
|
|
// the constant defaults.
|
|
//
|
|
// Outside of this module the image configuration is treated as an
|
|
// opaque blob and it is thus returned as an already serialised byte
|
|
// array and its SHA256-hash.
|
|
func configLayer(arch string, hashes []string, cmd string) ConfigLayer {
|
|
c := imageConfig{}
|
|
c.Architecture = arch
|
|
c.OS = os
|
|
c.RootFS.FSType = fsType
|
|
c.RootFS.DiffIDs = hashes
|
|
if cmd != "" {
|
|
c.Config.Cmd = []string{cmd}
|
|
}
|
|
c.Config.Env = []string{"SSL_CERT_FILE=/etc/ssl/certs/ca-bundle.crt"}
|
|
|
|
j, _ := json.Marshal(c)
|
|
|
|
return ConfigLayer{
|
|
Config: j,
|
|
SHA256: fmt.Sprintf("%x", sha256.Sum256(j)),
|
|
}
|
|
}
|
|
|
|
// Manifest creates an image manifest from the specified layer entries
|
|
// and returns its JSON-serialised form as well as the configuration
|
|
// layer.
|
|
//
|
|
// Callers do not need to set the media type for the layer entries.
|
|
func Manifest(arch string, layers []Entry, cmd string) (json.RawMessage, ConfigLayer) {
|
|
// Sort layers by their merge rating, from highest to lowest.
|
|
// This makes it likely for a contiguous chain of shared image
|
|
// layers to appear at the beginning of a layer.
|
|
//
|
|
// Due to moby/moby#38446 Docker considers the order of layers
|
|
// when deciding which layers to download again.
|
|
sort.Slice(layers, func(i, j int) bool {
|
|
return layers[i].MergeRating > layers[j].MergeRating
|
|
})
|
|
|
|
hashes := make([]string, len(layers))
|
|
for i, l := range layers {
|
|
hashes[i] = l.TarHash
|
|
l.MediaType = LayerType
|
|
l.TarHash = ""
|
|
layers[i] = l
|
|
}
|
|
|
|
c := configLayer(arch, hashes, cmd)
|
|
|
|
m := manifest{
|
|
SchemaVersion: schemaVersion,
|
|
MediaType: ManifestType,
|
|
Config: Entry{
|
|
MediaType: configType,
|
|
Size: int64(len(c.Config)),
|
|
Digest: "sha256:" + c.SHA256,
|
|
},
|
|
Layers: layers,
|
|
}
|
|
|
|
j, _ := json.Marshal(m)
|
|
|
|
return json.RawMessage(j), c
|
|
}
|