Files
LocalAI/core/http/middleware/failover_test.go
T
Ettore Di Giacinto f28d07b09d fix(failover): spill capacity and disabled targets without tripping them
An admission rejection or a disabled target moves the request to the
next target through Attempt.Skip, which records no failure. A 4xx
response no longer counts as a success. Requests skip body recording
when no chain is configured, and stop it once the model is known not
to be a chain.

Assisted-by: Claude:claude-opus-5-5
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
2026-09-27 07:42:20 +00:00

311 lines
12 KiB
Go

package middleware
import (
"bytes"
"context"
"errors"
"io"
"mime/multipart"
"net/http"
"net/http/httptest"
"os"
"path/filepath"
"strings"
"sync"
"testing/iotest"
"github.com/labstack/echo/v4"
"github.com/mudler/LocalAI/core/config"
"github.com/mudler/LocalAI/core/schema"
"github.com/mudler/LocalAI/core/services/failover"
"github.com/mudler/LocalAI/core/services/routing/admission"
"github.com/mudler/LocalAI/pkg/model"
"github.com/mudler/LocalAI/pkg/system"
. "github.com/onsi/ginkgo/v2"
. "github.com/onsi/gomega"
)
var _ = Describe("failover chains in the request pipeline", func() {
var (
app *echo.Echo
fm *failover.Manager
re *RequestExtractor
limiter *admission.Limiter
mu sync.Mutex
calls []string
behavior map[string]func(c echo.Context) error
)
served := func(c echo.Context) error {
cfg := c.Get(CONTEXT_LOCALS_KEY_MODEL_CONFIG).(*config.ModelConfig)
return c.JSON(http.StatusOK, map[string]string{"served": cfg.Name})
}
handler := func(c echo.Context) error {
cfg := c.Get(CONTEXT_LOCALS_KEY_MODEL_CONFIG).(*config.ModelConfig)
mu.Lock()
calls = append(calls, cfg.Name)
b := behavior[cfg.Name]
mu.Unlock()
if b == nil {
return served(c)
}
return b(c)
}
post := func(path, body string) *httptest.ResponseRecorder {
req := httptest.NewRequest(http.MethodPost, path, strings.NewReader(body))
req.Header.Set("Content-Type", "application/json")
rec := httptest.NewRecorder()
app.ServeHTTP(rec, req)
return rec
}
chat := func(model string) *httptest.ResponseRecorder {
return post("/v1/chat/completions", `{"model":"`+model+`","messages":[{"role":"user","content":"hi"}]}`)
}
BeforeEach(func() {
calls = nil
behavior = map[string]func(c echo.Context) error{}
dir := GinkgoT().TempDir()
write := func(name, body string) {
Expect(os.WriteFile(filepath.Join(dir, name+".yaml"), []byte(body), 0o600)).To(Succeed())
}
write("a", "name: a\nbackend: fake-a\n")
write("b", "name: b\nbackend: fake-b\n")
write("plain", "name: plain\nbackend: fake-p\n")
write("chain", "name: chain\nfailover:\n targets:\n - model: a\n - model: b\n")
write("capped", "name: capped\nbackend: fake-c\nlimits:\n max_concurrent: 1\n")
write("off", "name: off\nbackend: fake-o\ndisabled: true\n")
write("chain-capped", "name: chain-capped\nfailover:\n targets:\n - model: capped\n - model: b\n")
write("chain-off", "name: chain-off\nfailover:\n targets:\n - model: off\n - model: b\n")
ss := &system.SystemState{Model: system.Model{ModelsPath: dir}}
appConfig := config.NewApplicationConfig()
appConfig.SystemState = ss
mcl := config.NewModelConfigLoader(dir)
Expect(mcl.LoadModelConfigsFromPath(dir)).To(Succeed())
re = NewRequestExtractor(mcl, model.NewModelLoader(ss), appConfig)
fm = failover.New(mcl)
re.SetFailoverManager(fm)
app = echo.New()
// echo's default handler hides internal error messages; the specs
// below check which target's error reached the client.
app.HTTPErrorHandler = func(err error, c echo.Context) {
code := http.StatusInternalServerError
var he *echo.HTTPError
if errors.As(err, &he) {
code = he.Code
}
_ = c.JSON(code, map[string]string{"error": err.Error()})
}
app.POST("/v1/chat/completions", handler,
re.SetModelAndConfig(func() schema.LocalAIRequest { return new(schema.OpenAIRequest) }))
app.POST("/v1/audio/transcriptions", handler,
re.SetModelAndConfig(func() schema.LocalAIRequest { return new(schema.OpenAIRequest) }))
limiter = admission.New()
app.POST("/v1/chat/admitted", handler,
re.SetModelAndConfig(func() schema.LocalAIRequest { return new(schema.OpenAIRequest) }),
AdmissionControl(limiter, nil))
// The real transcription route resolves a default model first, which
// parses the multipart form before SetModelAndConfig runs.
app.POST("/v1/audio/transcriptions-default", handler,
re.BuildFilteredFirstAvailableDefaultModel(config.NoFilterFn),
re.SetModelAndConfig(func() schema.LocalAIRequest { return new(schema.OpenAIRequest) }))
})
It("serves from the next target when the first fails before responding", func() {
behavior["a"] = func(echo.Context) error { return errors.New("dial tcp: connection refused") }
rec := chat("chain")
Expect(rec.Code).To(Equal(http.StatusOK))
Expect(rec.Body.String()).To(ContainSubstring(`"served":"b"`))
Expect(rec.Header().Get(HeaderServedModel)).To(Equal("b"))
Expect(rec.Header().Get(HeaderFailover)).To(Equal("fallback"))
Expect(calls).To(Equal([]string{"a", "b"}))
st, _ := fm.ChainStatus("chain")
Expect(st.Active).To(Equal("b"))
})
It("serves the primary without the failover header", func() {
rec := chat("chain")
Expect(rec.Header().Get(HeaderServedModel)).To(Equal("a"))
Expect(rec.Header().Get(HeaderFailover)).To(BeEmpty())
})
It("drops a buffered 5xx response and retries", func() {
behavior["a"] = func(c echo.Context) error {
return c.JSON(http.StatusServiceUnavailable, map[string]string{"error": "no healthy nodes"})
}
rec := chat("chain")
Expect(rec.Code).To(Equal(http.StatusOK))
Expect(rec.Body.String()).ToNot(ContainSubstring("no healthy nodes"))
})
It("does not retry after streaming started, and trips the target", func() {
behavior["a"] = func(c echo.Context) error {
c.Response().Header().Set("Content-Type", "text/event-stream")
_, _ = c.Response().Write([]byte("data: x\n\n"))
c.Response().Flush()
return errors.New("connection reset by peer")
}
rec := chat("chain")
Expect(rec.Body.String()).To(HavePrefix("data: x"))
Expect(calls).To(Equal([]string{"a"}))
st, _ := fm.ChainStatus("chain")
Expect(st.Targets[0].State).To(Equal(failover.StateDown))
})
It("does not retry or trip on 4xx", func() {
behavior["a"] = func(echo.Context) error { return echo.NewHTTPError(http.StatusBadRequest, "bad") }
rec := chat("chain")
Expect(rec.Code).To(Equal(http.StatusBadRequest))
Expect(calls).To(Equal([]string{"a"}))
st, _ := fm.ChainStatus("chain")
Expect(st.Targets[0].State).To(Equal(failover.StateHealthy))
})
It("does not retry when the client cancelled", func() {
ctx, cancel := context.WithCancel(context.Background())
behavior["a"] = func(echo.Context) error { cancel(); return context.Canceled }
req := httptest.NewRequest(http.MethodPost, "/v1/chat/completions",
strings.NewReader(`{"model":"chain","messages":[{"role":"user","content":"hi"}]}`)).WithContext(ctx)
req.Header.Set("Content-Type", "application/json")
app.ServeHTTP(httptest.NewRecorder(), req)
Expect(calls).To(Equal([]string{"a"}))
st, _ := fm.ChainStatus("chain")
Expect(st.Targets[0].State).To(Equal(failover.StateHealthy))
})
It("gives each attempt a fresh request", func() {
behavior["a"] = func(c echo.Context) error {
in := c.Get(CONTEXT_LOCALS_KEY_LOCALAI_REQUEST).(*schema.OpenAIRequest)
in.Messages = nil
return errors.New("dial tcp: connection refused")
}
behavior["b"] = func(c echo.Context) error {
in := c.Get(CONTEXT_LOCALS_KEY_LOCALAI_REQUEST).(*schema.OpenAIRequest)
Expect(in.Messages).To(HaveLen(1))
return served(c)
}
Expect(chat("chain").Code).To(Equal(http.StatusOK))
})
It("degraded: tries every target in priority order and returns the last error", func() {
behavior["a"] = func(echo.Context) error { return errors.New("dial tcp: a down") }
behavior["b"] = func(echo.Context) error { return errors.New("dial tcp: b down") }
chat("chain") // trips both
calls = nil
rec := chat("chain")
Expect(calls).To(Equal([]string{"a", "b"}))
Expect(rec.Code).To(Equal(http.StatusInternalServerError))
Expect(rec.Body.String()).To(ContainSubstring("b down"))
Expect(rec.Header().Get(HeaderFailover)).To(Equal("degraded"))
})
DescribeTable("replays a multipart body for the next target", func(path string) {
var body bytes.Buffer
mw := multipart.NewWriter(&body)
_ = mw.WriteField("model", "chain")
fw, _ := mw.CreateFormFile("file", "a.wav")
_, _ = fw.Write(bytes.Repeat([]byte{7}, 4096))
Expect(mw.Close()).To(Succeed())
size := func(c echo.Context) int64 {
fh, err := c.FormFile("file")
Expect(err).ToNot(HaveOccurred())
f, _ := fh.Open()
n, _ := io.Copy(io.Discard, f)
return n
}
behavior["a"] = func(c echo.Context) error { size(c); return errors.New("dial tcp: refused") }
behavior["b"] = func(c echo.Context) error {
Expect(size(c)).To(Equal(int64(4096)))
return served(c)
}
req := httptest.NewRequest(http.MethodPost, path, &body)
req.Header.Set("Content-Type", mw.FormDataContentType())
rec := httptest.NewRecorder()
app.ServeHTTP(rec, req)
Expect(rec.Code).To(Equal(http.StatusOK), rec.Body.String())
Expect(calls).To(Equal([]string{"a", "b"}))
},
Entry("read by the handler", "/v1/audio/transcriptions"),
Entry("parsed before SetModelAndConfig", "/v1/audio/transcriptions-default"),
)
It("spills an admission rejection to the next target without tripping it", func() {
release, ok := limiter.Acquire("capped", 1)
Expect(ok).To(BeTrue())
defer release()
rec := post("/v1/chat/admitted", `{"model":"chain-capped","messages":[{"role":"user","content":"hi"}]}`)
Expect(rec.Code).To(Equal(http.StatusOK), rec.Body.String())
Expect(rec.Body.String()).To(ContainSubstring(`"served":"b"`))
Expect(rec.Header().Get("Retry-After")).To(BeEmpty())
st, _ := fm.ChainStatus("chain-capped")
Expect(st.Targets[0].State).To(Equal(failover.StateHealthy))
Expect(st.Active).To(Equal("capped"))
})
It("skips a disabled target without tripping it", func() {
rec := chat("chain-off")
Expect(rec.Code).To(Equal(http.StatusOK), rec.Body.String())
Expect(rec.Body.String()).To(ContainSubstring(`"served":"b"`))
Expect(calls).To(Equal([]string{"b"}))
st, _ := fm.ChainStatus("chain-off")
Expect(st.Targets[0].State).To(Equal(failover.StateHealthy))
})
It("counts a 4xx response as neither success nor failure", func() {
behavior["a"] = func(echo.Context) error { return errors.New("dial tcp: a down") }
behavior["b"] = func(echo.Context) error { return errors.New("dial tcp: b down") }
chat("chain") // trips both
behavior["a"] = func(c echo.Context) error {
return c.JSON(http.StatusBadRequest, map[string]string{"error": "bad"})
}
rec := chat("chain")
Expect(rec.Code).To(Equal(http.StatusBadRequest))
st, _ := fm.ChainStatus("chain")
// a is a cold local target: a success would have recovered it.
Expect(st.Targets[0].State).To(Equal(failover.StateDown))
})
It("stops recording the body once the model is known not to be a chain", func() {
behavior["plain"] = func(c echo.Context) error {
rb, ok := c.Request().Body.(*replayBody)
Expect(ok).To(BeTrue())
Expect(rb.replayable()).To(BeFalse())
Expect(rb.buf.Cap()).To(BeZero())
return served(c)
}
Expect(chat("plain").Code).To(Equal(http.StatusOK))
})
It("does not record the body without a failover manager", func() {
re.SetFailoverManager(nil)
behavior["plain"] = func(c echo.Context) error {
_, ok := c.Request().Body.(*replayBody)
Expect(ok).To(BeFalse())
return served(c)
}
Expect(chat("plain").Code).To(Equal(http.StatusOK))
})
It("releases the recorded bytes on overflow", func() {
// One byte per read, so some bytes are recorded before the limit is hit.
rb := &replayBody{src: io.NopCloser(iotest.OneByteReader(bytes.NewReader(make([]byte, 64)))), limit: 16}
_, _ = io.ReadAll(rb)
Expect(rb.replayable()).To(BeFalse())
Expect(rb.buf.Cap()).To(BeZero())
})
It("leaves plain models untouched", func() {
behavior["plain"] = func(c echo.Context) error {
return c.JSON(http.StatusInternalServerError, map[string]string{"error": "boom"})
}
rec := chat("plain")
Expect(rec.Code).To(Equal(http.StatusInternalServerError))
Expect(rec.Body.String()).To(ContainSubstring("boom"))
Expect(rec.Header().Get(HeaderServedModel)).To(BeEmpty())
})
})