20187: Use validate func instead of making cache discoverydoc-aware.

Arvados-DCO-1.1-Signed-off-by: Tom Clegg <tom@curii.com>

diff --git a/lib/controller/handler.go b/lib/controller/handler.go
index c213c897c35dcaa734b5869ca6567047bf07a369..9054dd633023309cc117c21bdb38d4740e5b0c7e 100644 (file)
--- a/lib/controller/handler.go
+++ b/lib/controller/handler.go
@@ -171,7 +171,7 @@ func (h *Handler) setup() {
                Name: "arvados-controller",
        }
        h.cache = map[string]*cacheEnt{
-               "/discovery/v1/apis/arvados/v1/rest": &cacheEnt{validateDD: true},
+               "/discovery/v1/apis/arvados/v1/rest": &cacheEnt{validate: validateDiscoveryDoc},
        }
 
        go h.trashSweepWorker()
@@ -222,7 +222,7 @@ func (h *Handler) limitLogCreateRequests(w http.ResponseWriter, req *http.Reques
 // cacheEnt implements a basic stale-while-revalidate cache, suitable
 // for the Arvados discovery document.
 type cacheEnt struct {
-       validateDD   bool
+       validate     func(body []byte) error
        mtx          sync.Mutex
        header       http.Header
        body         []byte
@@ -278,12 +278,9 @@ func (ent *cacheEnt) refresh(path string, do func(*http.Request) (*http.Response
                        header[k] = v
                }
        }
-       if ent.validateDD {
-               var dd arvados.DiscoveryDocument
-               if err := json.Unmarshal(body, &dd); err != nil {
-                       return nil, nil, fmt.Errorf("error decoding JSON response: %w", err)
-               } else if dd.BasePath == "" {
-                       return nil, nil, errors.New("error in discovery document: no value for basePath")
+       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) {
@@ -358,3 +355,15 @@ 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
+}