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feat(builder): Implement build cache for manifests & layers

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Implements a cache that keeps track of:

a) Manifests that have already been built (for up to 6 hours)
b) Layers that have already been seen (and uploaded to GCS)

This significantly speeds up response times for images that are full
or partial matches with previous images served by an instance.
This commit is contained in:
Vincent Ambo 2019-08-14 20:02:52 +01:00 • committed by Vincent Ambo
parent 58380e3313
commit cf227c153f
3 changed files with 159 additions and 49 deletions
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108
tools/nixery/server/builder/builder.go
View file

@ -69,10 +69,10 @@ func ImageFromName(name string, tag string) Image {
//
// The later field is simply treated as opaque JSON and passed through.
type BuildResult struct {
Error string `json:"error"`
Pkgs []string `json:"pkgs"`
Error string `json:"error"`
Pkgs []string `json:"pkgs"`
Manifest json.RawMessage `json:"manifest"`
Manifest json.RawMessage `json:"manifest"`
LayerLocations map[string]struct {
Path string `json:"path"`
Md5 []byte `json:"md5"`
@ -99,50 +99,57 @@ func convenienceNames(packages []string) []string {
// Call out to Nix and request that an image be built. Nix will, upon success,
// return a manifest for the container image.
func BuildImage(ctx *context.Context, cfg *config.Config, image *Image, bucket *storage.BucketHandle) (*BuildResult, error) {
packages, err := json.Marshal(image.Packages)
if err != nil {
return nil, err
func BuildImage(ctx *context.Context, cfg *config.Config, cache *BuildCache, image *Image, bucket *storage.BucketHandle) (*BuildResult, error) {
resultFile, cached := cache.manifestFromCache(image)
if !cached {
packages, err := json.Marshal(image.Packages)
if err != nil {
return nil, err
}
args := []string{
"--argstr", "name", image.Name,
"--argstr", "packages", string(packages),
}
if cfg.Pkgs != nil {
args = append(args, "--argstr", "pkgSource", cfg.Pkgs.Render(image.Tag))
}
cmd := exec.Command("nixery-build-image", args...)
outpipe, err := cmd.StdoutPipe()
if err != nil {
return nil, err
}
errpipe, err := cmd.StderrPipe()
if err != nil {
return nil, err
}
if err = cmd.Start(); err != nil {
log.Println("Error starting nix-build:", err)
return nil, err
}
log.Printf("Started Nix image build for '%s'", image.Name)
stdout, _ := ioutil.ReadAll(outpipe)
stderr, _ := ioutil.ReadAll(errpipe)
if err = cmd.Wait(); err != nil {
// TODO(tazjin): Propagate errors upwards in a usable format.
log.Printf("nix-build execution error: %s\nstdout: %s\nstderr: %s\n", err, stdout, stderr)
return nil, err
}
log.Println("Finished Nix image build")
resultFile = strings.TrimSpace(string(stdout))
cache.cacheManifest(image, resultFile)
}
args := []string{
"--argstr", "name", image.Name,
"--argstr", "packages", string(packages),
}
if cfg.Pkgs != nil {
args = append(args, "--argstr", "pkgSource", cfg.Pkgs.Render(image.Tag))
}
cmd := exec.Command("nixery-build-image", args...)
outpipe, err := cmd.StdoutPipe()
if err != nil {
return nil, err
}
errpipe, err := cmd.StderrPipe()
if err != nil {
return nil, err
}
if err = cmd.Start(); err != nil {
log.Println("Error starting nix-build:", err)
return nil, err
}
log.Printf("Started Nix image build for '%s'", image.Name)
stdout, _ := ioutil.ReadAll(outpipe)
stderr, _ := ioutil.ReadAll(errpipe)
if err = cmd.Wait(); err != nil {
// TODO(tazjin): Propagate errors upwards in a usable format.
log.Printf("nix-build execution error: %s\nstdout: %s\nstderr: %s\n", err, stdout, stderr)
return nil, err
}
log.Println("Finished Nix image build")
buildOutput, err := ioutil.ReadFile(strings.TrimSpace(string(stdout)))
buildOutput, err := ioutil.ReadFile(resultFile)
if err != nil {
return nil, err
}
@ -151,15 +158,20 @@ func BuildImage(ctx *context.Context, cfg *config.Config, image *Image, bucket *
// contained layers to the bucket. Only the manifest itself is
// re-serialised to JSON and returned.
var result BuildResult
err = json.Unmarshal(buildOutput, &result)
if err != nil {
return nil, err
}
for layer, meta := range result.LayerLocations {
err = uploadLayer(ctx, bucket, layer, meta.Path, meta.Md5)
if err != nil {
return nil, err
if !cache.hasSeenLayer(layer) {
err = uploadLayer(ctx, bucket, layer, meta.Path, meta.Md5)
if err != nil {
return nil, err
}
cache.sawLayer(layer)
}
}