X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/b5a8acaf05b8fe8ef00855b3280f3b019539eda3..78910a657391081eb46b2b7a84d985b7daea6389:/lib/controller/handler.go diff --git a/lib/controller/handler.go b/lib/controller/handler.go index 5d6bd9570c..045e4a8c9c 100644 --- a/lib/controller/handler.go +++ b/lib/controller/handler.go @@ -6,12 +6,17 @@ package controller import ( "context" + "encoding/json" + "errors" "fmt" + "io/ioutil" + "mime" "net/http" "net/http/httptest" "net/url" "strings" "sync" + "time" "git.arvados.org/arvados.git/lib/controller/api" "git.arvados.org/arvados.git/lib/controller/federation" @@ -20,6 +25,7 @@ import ( "git.arvados.org/arvados.git/lib/controller/router" "git.arvados.org/arvados.git/lib/ctrlctx" "git.arvados.org/arvados.git/sdk/go/arvados" + "git.arvados.org/arvados.git/sdk/go/ctxlog" "git.arvados.org/arvados.git/sdk/go/health" "git.arvados.org/arvados.git/sdk/go/httpserver" @@ -39,6 +45,8 @@ type Handler struct { insecureClient *http.Client dbConnector ctrlctx.DBConnector limitLogCreate chan struct{} + + cache map[string]*cacheEnt } func (h *Handler) ServeHTTP(w http.ResponseWriter, req *http.Request) { @@ -95,8 +103,12 @@ func (h *Handler) setup() { healthFuncs := make(map[string]health.Func) h.dbConnector = ctrlctx.DBConnector{PostgreSQL: h.Cluster.PostgreSQL} + go func() { + <-h.BackgroundContext.Done() + h.dbConnector.Close() + }() oidcAuthorizer := localdb.OIDCAccessTokenAuthorizer(h.Cluster, h.dbConnector.GetDB) - h.federation = federation.New(h.Cluster, &healthFuncs) + h.federation = federation.New(h.BackgroundContext, h.Cluster, &healthFuncs, h.dbConnector.GetDB) rtr := router.New(h.federation, router.Config{ MaxRequestSize: h.Cluster.API.MaxRequestSize, WrapCalls: api.ComposeWrappers( @@ -158,6 +170,9 @@ func (h *Handler) setup() { h.proxy = &proxy{ Name: "arvados-controller", } + h.cache = map[string]*cacheEnt{ + "/discovery/v1/apis/arvados/v1/rest": &cacheEnt{validate: validateDiscoveryDoc}, + } go h.trashSweepWorker() go h.containerLogSweepWorker() @@ -204,7 +219,127 @@ func (h *Handler) limitLogCreateRequests(w http.ResponseWriter, req *http.Reques next.ServeHTTP(w, req) } +// cacheEnt implements a basic stale-while-revalidate cache, suitable +// for the Arvados discovery document. +type cacheEnt struct { + validate func(body []byte) error + mtx sync.Mutex + header http.Header + body []byte + expireAfter time.Time + refreshAfter time.Time + refreshLock sync.Mutex +} + +const ( + cacheTTL = 5 * time.Minute + cacheExpire = 24 * time.Hour +) + +func (ent *cacheEnt) refresh(path string, do func(*http.Request) (*http.Response, error)) (http.Header, []byte, error) { + ent.refreshLock.Lock() + defer ent.refreshLock.Unlock() + if header, body, needRefresh := ent.response(); !needRefresh { + // another goroutine refreshed successfully while we + // were waiting for refreshLock + return header, body, nil + } else if body != nil { + // Cache is present, but expired. We'll try to refresh + // below. Meanwhile, other refresh() calls will queue + // up for refreshLock -- and we don't want them to + // turn into N upstream requests, even if upstream is + // failing. (If we succeed we'll update the expiry + // time again below with the real cacheTTL -- this + // just takes care of the error case.) + ent.mtx.Lock() + ent.refreshAfter = time.Now().Add(time.Second) + ent.mtx.Unlock() + } + + ctx, cancel := context.WithDeadline(context.Background(), time.Now().Add(time.Minute)) + defer cancel() + // 0.0.0.0:0 is just a placeholder here -- do(), which is + // localClusterRequest(), will replace the scheme and host + // parts with the real proxy destination. + req, err := http.NewRequestWithContext(ctx, http.MethodGet, "http://0.0.0.0:0/"+path, nil) + if err != nil { + return nil, nil, err + } + resp, err := do(req) + if err != nil { + return nil, nil, err + } + if resp.StatusCode != http.StatusOK { + return nil, nil, fmt.Errorf("HTTP status %d", resp.StatusCode) + } + body, err := ioutil.ReadAll(resp.Body) + if err != nil { + return nil, nil, fmt.Errorf("Read error: %w", err) + } + header := http.Header{} + for k, v := range resp.Header { + if !dropHeaders[k] && k != "X-Request-Id" { + header[k] = v + } + } + if ent.validate != nil { + if err := ent.validate(body); err != nil { + return nil, nil, err + } + } else if mediatype, _, err := mime.ParseMediaType(header.Get("Content-Type")); err == nil && mediatype == "application/json" { + if !json.Valid(body) { + return nil, nil, errors.New("invalid JSON encoding in response") + } + } + ent.mtx.Lock() + defer ent.mtx.Unlock() + ent.header = header + ent.body = body + ent.refreshAfter = time.Now().Add(cacheTTL) + ent.expireAfter = time.Now().Add(cacheExpire) + return ent.header, ent.body, nil +} + +func (ent *cacheEnt) response() (http.Header, []byte, bool) { + ent.mtx.Lock() + defer ent.mtx.Unlock() + if ent.expireAfter.Before(time.Now()) { + ent.header, ent.body, ent.refreshAfter = nil, nil, time.Time{} + } + return ent.header, ent.body, ent.refreshAfter.Before(time.Now()) +} + +func (ent *cacheEnt) ServeHTTP(ctx context.Context, w http.ResponseWriter, path string, do func(*http.Request) (*http.Response, error)) { + header, body, needRefresh := ent.response() + if body == nil { + // need to fetch before we can return anything + var err error + header, body, err = ent.refresh(path, do) + if err != nil { + http.Error(w, err.Error(), http.StatusBadGateway) + return + } + } else if needRefresh { + // re-fetch in background + go func() { + _, _, err := ent.refresh(path, do) + if err != nil { + ctxlog.FromContext(ctx).WithError(err).WithField("path", path).Warn("error refreshing cache") + } + }() + } + for k, v := range header { + w.Header()[k] = v + } + w.WriteHeader(http.StatusOK) + w.Write(body) +} + func (h *Handler) proxyRailsAPI(w http.ResponseWriter, req *http.Request, next http.Handler) { + if ent, ok := h.cache[req.URL.Path]; ok && req.Method == http.MethodGet { + ent.ServeHTTP(req.Context(), w, req.URL.Path, h.localClusterRequest) + return + } resp, err := h.localClusterRequest(req) n, err := h.proxy.ForwardResponse(w, resp, err) if err != nil { @@ -228,3 +363,15 @@ func findRailsAPI(cluster *arvados.Cluster) (*url.URL, bool, error) { } return best, cluster.TLS.Insecure, nil } + +func validateDiscoveryDoc(body []byte) error { + var dd arvados.DiscoveryDocument + err := json.Unmarshal(body, &dd) + if err != nil { + return fmt.Errorf("error decoding JSON response: %w", err) + } + if dd.BasePath == "" { + return errors.New("error in discovery document: no value for basePath") + } + return nil +}