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fix: data races on dynamic endpoint state #133

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fix: data races on dynamic endpoint state #133

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f718424
fix: data races on dynamic endpoint state
fzipi Aug 18, 2026
511a7ee
test: assert status in concurrent configuration test
fzipi Aug 19, 2026
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2 changes: 1 addition & 1 deletion .github/workflows/test.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -24,7 +24,7 @@ jobs:
cache: true

- name: Run Go Tests
run: go test -coverprofile=coverage.out ./...
run: go test -race -coverprofile=coverage.out ./...
lint:
runs-on: ubuntu-latest
steps:
Expand Down
17 changes: 6 additions & 11 deletions server/server.go
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Expand Up @@ -7,7 +7,6 @@ import (
"encoding/json"
"errors"
"fmt"
"hash/maphash"
"io"
"log"
"log/slog"
Expand All @@ -21,8 +20,7 @@ import (

var capabilities *CapabilitiesSpec
var dynamicEndpointMutex = sync.RWMutex{}
var dynamicEndpoints = map[uint64]reflectionSpec{}
var dynamicEndpointsHash = maphash.Hash{}
var dynamicEndpoints = map[string]reflectionSpec{}

//go:embed capabilities.yaml
var capabilitiesDescription []byte
Expand Down Expand Up @@ -172,9 +170,9 @@ func handleConfigureReflection(w http.ResponseWriter, r *http.Request) {

func handleReset(w http.ResponseWriter, r *http.Request) {
slog.Info("Received reset request. Discarding all endpoint configurations now")
for k := range dynamicEndpoints {
delete(dynamicEndpoints, k)
}
dynamicEndpointMutex.Lock()
defer dynamicEndpointMutex.Unlock()
clear(dynamicEndpoints)
}

func handleInspect(w http.ResponseWriter, r *http.Request) {
Expand Down Expand Up @@ -234,11 +232,8 @@ func decodeBody(spec *reflectionSpec) (string, error) {
return string(bodyBytes), nil
}

func computeEndpointKey(method string, url string) uint64 {
dynamicEndpointsHash.Reset()
dynamicEndpointsHash.WriteString(method)
dynamicEndpointsHash.WriteString(url)
return dynamicEndpointsHash.Sum64()
func computeEndpointKey(method string, url string) string {
return method + " " + url
}

func doReflect(w http.ResponseWriter, r *http.Request, spec *reflectionSpec) {
Expand Down
40 changes: 40 additions & 0 deletions server/server_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@ import (
"net/http"
"net/http/httptest"
"strings"
"sync"
"testing"

"github.com/stretchr/testify/suite"
Expand Down Expand Up @@ -555,3 +556,42 @@ func (s *serverTestSuite) TestInspect_LogContent() {
s.Contains(logContent, "request.body.length.value=0")
s.Contains(logContent, "request.body.length.unit=B")
}

// Endpoint configuration state is package-global; concurrent requests must not race on it.
func (s *serverTestSuite) TestConcurrentConfigurationAccess() {
server := httptest.NewServer(Handler())
s.T().Cleanup(server.Close)
s.T().Cleanup(func() { clear(dynamicEndpoints) })

client := http.Client{}
spec := `{"endpoints":[{"method":"GET","url":"/concurrent"}],"status":201}`

wg := sync.WaitGroup{}
for i := 0; i < 20; i++ {
wg.Add(3)
go func() {
defer wg.Done()
response, err := client.Post(server.URL+"/configure_reflection", "application/json", strings.NewReader(spec))
if s.NoError(err) {
s.NoError(response.Body.Close())
}
}()
go func() {
defer wg.Done()
response, err := client.Get(server.URL + "/concurrent")

@theseion theseion Aug 18, 2026

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Wouldn't the error be returned here? 404, since reset was called before.

@fzipi fzipi Aug 19, 2026

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No — that path never 404s. Everything unmatched falls through to handleDefault on /, which is the black hole: it writes an empty 200. I verified it against a live Handler() with /concurrent unconfigured and got 200.

So the only two outcomes here are 201 while the configuration is live and 200 once /reset has discarded it, depending on how the goroutines interleave. The test was ignoring the status entirely, which is what made the question reasonable — it now asserts the response is one of those two, so a genuine 404 or 500 regression would fail it. Pushed as a follow-up commit.

if s.NoError(err) {
s.NoError(response.Body.Close())
}
}()
go func() {
defer wg.Done()
request, err := http.NewRequest(http.MethodPut, server.URL+"/reset", nil)
s.Require().NoError(err)
response, err := client.Do(request)
if s.NoError(err) {
s.NoError(response.Body.Close())
}
}()
}
wg.Wait()
}