fix(server): Thread request context to all relevant places

Previously background contexts where created where necessary (e.g. in
GCS interactions). Should I begin to use request timeouts or other
context-dependent things in the future, it's useful to have the actual
HTTP request context around.

This threads the request context through the application to all places
that need it.
This commit is contained in:
Vincent Ambo 2019-10-28 18:32:02 +01:00 committed by Vincent Ambo
parent 30e618b65b
commit d8fba23365
6 changed files with 20 additions and 23 deletions

View file

@ -375,7 +375,7 @@ func (b *byteCounter) Write(p []byte) (n int, err error) {
// image manifest.
func uploadHashLayer(ctx context.Context, s *State, key string, lw layerWriter) (*manifest.Entry, error) {
path := "staging/" + key
sha256sum, size, err := s.Storage.Persist(path, func(sw io.Writer) (string, int64, error) {
sha256sum, size, err := s.Storage.Persist(ctx, path, func(sw io.Writer) (string, int64, error) {
// Sets up a "multiwriter" that simultaneously runs both hash
// algorithms and uploads to the storage backend.
shasum := sha256.New()
@ -399,7 +399,7 @@ func uploadHashLayer(ctx context.Context, s *State, key string, lw layerWriter)
// Hashes are now known and the object is in the bucket, what
// remains is to move it to the correct location and cache it.
err = s.Storage.Move("staging/"+key, "layers/"+sha256sum)
err = s.Storage.Move(ctx, "staging/"+key, "layers/"+sha256sum)
if err != nil {
log.WithError(err).WithField("layer", key).
Error("failed to move layer from staging")

View file

@ -120,7 +120,7 @@ func manifestFromCache(ctx context.Context, s *State, key string) (json.RawMessa
return m, true
}
r, err := s.Storage.Fetch("manifests/" + key)
r, err := s.Storage.Fetch(ctx, "manifests/"+key)
if err != nil {
log.WithError(err).WithFields(log.Fields{
"manifest": key,
@ -152,7 +152,7 @@ func cacheManifest(ctx context.Context, s *State, key string, m json.RawMessage)
go s.Cache.localCacheManifest(key, m)
path := "manifests/" + key
_, size, err := s.Storage.Persist(path, func(w io.Writer) (string, int64, error) {
_, size, err := s.Storage.Persist(ctx, path, func(w io.Writer) (string, int64, error) {
size, err := io.Copy(w, bytes.NewReader([]byte(m)))
return "", size, err
})
@ -180,7 +180,7 @@ func layerFromCache(ctx context.Context, s *State, key string) (*manifest.Entry,
return entry, true
}
r, err := s.Storage.Fetch("builds/" + key)
r, err := s.Storage.Fetch(ctx, "builds/"+key)
if err != nil {
log.WithError(err).WithFields(log.Fields{
"layer": key,
@ -220,7 +220,7 @@ func cacheLayer(ctx context.Context, s *State, key string, entry manifest.Entry)
j, _ := json.Marshal(&entry)
path := "builds/" + key
_, _, err := s.Storage.Persist(path, func(w io.Writer) (string, int64, error) {
_, _, err := s.Storage.Persist(ctx, path, func(w io.Writer) (string, int64, error) {
size, err := io.Copy(w, bytes.NewReader(j))
return "", size, err
})

View file

@ -26,7 +26,6 @@
package main
import (
"context"
"encoding/json"
"fmt"
"io/ioutil"
@ -110,7 +109,6 @@ func writeError(w http.ResponseWriter, status int, code, message string) {
}
type registryHandler struct {
ctx context.Context
state *builder.State
}
@ -132,7 +130,7 @@ func (h *registryHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
}).Info("requesting image manifest")
image := builder.ImageFromName(imageName, imageTag)
buildResult, err := builder.BuildImage(h.ctx, h.state, &image)
buildResult, err := builder.BuildImage(r.Context(), h.state, &image)
if err != nil {
writeError(w, 500, "UNKNOWN", "image build failure")
@ -211,7 +209,6 @@ func main() {
log.WithField("backend", s.Name()).Info("initialised storage backend")
ctx := context.Background()
cache, err := builder.NewCache()
if err != nil {
log.WithError(err).Fatal("failed to instantiate build cache")
@ -240,7 +237,6 @@ func main() {
// All /v2/ requests belong to the registry handler.
http.Handle("/v2/", &registryHandler{
ctx: ctx,
state: &state,
})

View file

@ -2,6 +2,7 @@
package storage
import (
"context"
"fmt"
"io"
"net/http"
@ -34,7 +35,7 @@ func (b *FSBackend) Name() string {
return fmt.Sprintf("Filesystem (%s)", b.path)
}
func (b *FSBackend) Persist(key string, f func(io.Writer) (string, int64, error)) (string, int64, error) {
func (b *FSBackend) Persist(ctx context.Context, key string, f Persister) (string, int64, error) {
full := path.Join(b.path, key)
dir := path.Dir(full)
err := os.MkdirAll(dir, 0755)
@ -53,12 +54,12 @@ func (b *FSBackend) Persist(key string, f func(io.Writer) (string, int64, error)
return f(file)
}
func (b *FSBackend) Fetch(key string) (io.ReadCloser, error) {
func (b *FSBackend) Fetch(ctx context.Context, key string) (io.ReadCloser, error) {
full := path.Join(b.path, key)
return os.Open(full)
}
func (b *FSBackend) Move(old, new string) error {
func (b *FSBackend) Move(ctx context.Context, old, new string) error {
newpath := path.Join(b.path, new)
err := os.MkdirAll(path.Dir(newpath), 0755)
if err != nil {

View file

@ -66,8 +66,7 @@ func (b *GCSBackend) Name() string {
return "Google Cloud Storage (" + b.bucket + ")"
}
func (b *GCSBackend) Persist(path string, f func(io.Writer) (string, int64, error)) (string, int64, error) {
ctx := context.Background()
func (b *GCSBackend) Persist(ctx context.Context, path string, f Persister) (string, int64, error) {
obj := b.handle.Object(path)
w := obj.NewWriter(ctx)
@ -80,8 +79,7 @@ func (b *GCSBackend) Persist(path string, f func(io.Writer) (string, int64, erro
return hash, size, w.Close()
}
func (b *GCSBackend) Fetch(path string) (io.ReadCloser, error) {
ctx := context.Background()
func (b *GCSBackend) Fetch(ctx context.Context, path string) (io.ReadCloser, error) {
obj := b.handle.Object(path)
// Probe whether the file exists before trying to fetch it
@ -98,8 +96,7 @@ func (b *GCSBackend) Fetch(path string) (io.ReadCloser, error) {
//
// The Go API for Cloud Storage does not support renaming objects, but
// the HTTP API does. The code below makes the relevant call manually.
func (b *GCSBackend) Move(old, new string) error {
ctx := context.Background()
func (b *GCSBackend) Move(ctx context.Context, old, new string) error {
creds, err := google.FindDefaultCredentials(ctx, gcsScope)
if err != nil {
return err

View file

@ -4,10 +4,13 @@
package storage
import (
"context"
"io"
"net/http"
)
type Persister = func(io.Writer) (string, int64, error)
type Backend interface {
// Name returns the name of the storage backend, for use in
// log messages and such.
@ -19,14 +22,14 @@ type Backend interface {
// It needs to return the SHA256 hash of the data written as
// well as the total number of bytes, as those are required
// for the image manifest.
Persist(string, func(io.Writer) (string, int64, error)) (string, int64, error)
Persist(context.Context, string, Persister) (string, int64, error)
// Fetch retrieves data from the storage backend.
Fetch(path string) (io.ReadCloser, error)
Fetch(ctx context.Context, path string) (io.ReadCloser, error)
// Move renames a path inside the storage backend. This is
// used for staging uploads while calculating their hashes.
Move(old, new string) error
Move(ctx context.Context, old, new string) error
// Serve provides a handler function to serve HTTP requests
// for layers in the storage backend.