Sub2API v1.0 - AI API 网关（二开初始版本，基于上游 Wei-Shaw/sub2api）

backend/internal/service/gateway_forward_partial_usage_test.go

@@ -0,0 +1,340 @@
+package service
+
+import (
+	"context"
+	"errors"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/gin-gonic/gin"
+	"github.com/stretchr/testify/require"
+)
+
+type gatewayForwardErrorPolicyRepoStub struct {
+	AccountRepository
+	tempCalls           int
+	modelRateLimitCalls []gatewayForwardModelRateLimitCall
+}
+
+type gatewayForwardModelRateLimitCall struct {
+	accountID int64
+	scope     string
+}
+
+func (r *gatewayForwardErrorPolicyRepoStub) SetTempUnschedulable(context.Context, int64, time.Time, string) error {
+	r.tempCalls++
+	return nil
+}
+
+func (r *gatewayForwardErrorPolicyRepoStub) SetModelRateLimit(_ context.Context, id int64, scope string, _ time.Time, _ ...string) error {
+	r.modelRateLimitCalls = append(r.modelRateLimitCalls, gatewayForwardModelRateLimitCall{
+		accountID: id,
+		scope:     scope,
+	})
+	return nil
+}
+
+// 本文件覆盖 issue #5148：流式转发中途出错（缺失 terminal 事件、读错误等）时，
+// 已观测到的上游 usage 不得随错误一起被丢弃，Forward 必须把部分结果与错误一同
+// 返回，供 handler 照常提交 usage 记录。
+
+func newForwardPartialUsageServiceForTest(upstream *anthropicHTTPUpstreamRecorder) *GatewayService {
+	cfg := &config.Config{
+		Gateway: config.GatewayConfig{
+			MaxLineSize: defaultMaxLineSize,
+		},
+	}
+	return &GatewayService{
+		cfg:                  cfg,
+		responseHeaderFilter: compileResponseHeaderFilter(cfg),
+		httpUpstream:         upstream,
+		rateLimitService:     &RateLimitService{},
+		deferredService:      &DeferredService{},
+	}
+}
+
+func newAnthropicOAuthAccountForPartialUsageTest() *Account {
+	return &Account{
+		ID:          501,
+		Name:        "anthropic-oauth-partial-usage",
+		Platform:    PlatformAnthropic,
+		Type:        AccountTypeOAuth,
+		Concurrency: 1,
+		Credentials: map[string]any{
+			"access_token": "oauth-token",
+		},
+		Status:      StatusActive,
+		Schedulable: true,
+	}
+}
+
+func TestGatewayService_Forward_StreamMissingTerminalPreservesPartialUsage(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/messages", nil)
+
+	body := []byte(`{"model":"claude-3-5-sonnet-latest","stream":true,"messages":[{"role":"user","content":[{"type":"text","text":"hello"}]}]}`)
+	parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), PlatformAnthropic)
+	require.NoError(t, err)
+
+	// newapi 等聚合上游的典型失败形态：message_start/message_delta 携带 usage，
+	// 但流在 message_stop 前直接结束。
+	upstreamSSE := strings.Join([]string{
+		`event: message_start`,
+		`data: {"type":"message_start","message":{"id":"msg_1","type":"message","role":"assistant","model":"claude-3-5-sonnet-latest","content":[],"usage":{"input_tokens":11,"cache_read_input_tokens":7}}}`,
+		"",
+		`event: content_block_delta`,
+		`data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":"hi"}}`,
+		"",
+		`event: message_delta`,
+		`data: {"type":"message_delta","delta":{"stop_reason":null},"usage":{"output_tokens":5}}`,
+		"",
+		"",
+	}, "\n")
+	upstream := &anthropicHTTPUpstreamRecorder{resp: &http.Response{
+		StatusCode: http.StatusOK,
+		Header: http.Header{
+			"Content-Type": []string{"text/event-stream"},
+			"X-Request-Id": []string{"rid-partial"},
+		},
+		Body: io.NopCloser(strings.NewReader(upstreamSSE)),
+	}}
+	svc := newForwardPartialUsageServiceForTest(upstream)
+	account := newAnthropicOAuthAccountForPartialUsageTest()
+
+	result, err := svc.Forward(context.Background(), c, account, parsed)
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "missing terminal event")
+	require.NotNil(t, result, "流中断但已观测到 usage 时必须返回部分结果用于计费")
+	require.True(t, result.Stream)
+	require.Equal(t, 11, result.Usage.InputTokens)
+	require.Equal(t, 7, result.Usage.CacheReadInputTokens)
+	require.Equal(t, 5, result.Usage.OutputTokens)
+	require.Equal(t, "rid-partial", result.RequestID)
+	require.NotNil(t, result.FirstTokenMs)
+}
+
+func TestGatewayService_Forward_StreamReadErrorAfterOutputPreservesPartialUsage(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/messages", nil)
+
+	body := []byte(`{"model":"claude-3-5-sonnet-latest","stream":true,"messages":[{"role":"user","content":[{"type":"text","text":"hello"}]}]}`)
+	parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), PlatformAnthropic)
+	require.NoError(t, err)
+
+	// message_start 已写出（含 usage），随后上游连接异常中断。
+	upstream := &anthropicHTTPUpstreamRecorder{resp: &http.Response{
+		StatusCode: http.StatusOK,
+		Header:     http.Header{"Content-Type": []string{"text/event-stream"}},
+		Body: &streamReadCloser{
+			payload: []byte("data: {\"type\":\"message_start\",\"message\":{\"usage\":{\"input_tokens\":9,\"cache_creation_input_tokens\":4}}}\n\n"),
+			err:     io.ErrUnexpectedEOF,
+		},
+	}}
+	svc := newForwardPartialUsageServiceForTest(upstream)
+	account := newAnthropicOAuthAccountForPartialUsageTest()
+
+	result, err := svc.Forward(context.Background(), c, account, parsed)
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "stream read error")
+	require.NotNil(t, result, "已写出内容后的读错误必须保留部分 usage")
+	require.Equal(t, 9, result.Usage.InputTokens)
+	require.Equal(t, 4, result.Usage.CacheCreationInputTokens)
+}
+
+func TestGatewayService_Forward_StreamErrorWithoutUsageReturnsNilResult(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/messages", nil)
+
+	body := []byte(`{"model":"claude-3-5-sonnet-latest","stream":true,"messages":[{"role":"user","content":[{"type":"text","text":"hello"}]}]}`)
+	parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), PlatformAnthropic)
+	require.NoError(t, err)
+
+	// 只有 ping、没有任何 usage 的流中断：不应产生零 usage 的幽灵账单记录。
+	upstream := &anthropicHTTPUpstreamRecorder{resp: &http.Response{
+		StatusCode: http.StatusOK,
+		Header:     http.Header{"Content-Type": []string{"text/event-stream"}},
+		Body:       io.NopCloser(strings.NewReader("event: ping\ndata: {\"type\": \"ping\"}\n\n")),
+	}}
+	svc := newForwardPartialUsageServiceForTest(upstream)
+	account := newAnthropicOAuthAccountForPartialUsageTest()
+
+	result, err := svc.Forward(context.Background(), c, account, parsed)
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "missing terminal event")
+	require.Nil(t, result, "无已观测 usage 时不应返回部分结果")
+}
+
+func TestGatewayService_Forward_FailoverErrorKeepsNilResult(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/messages", nil)
+
+	body := []byte(`{"model":"claude-3-5-sonnet-latest","stream":true,"messages":[{"role":"user","content":[{"type":"text","text":"hello"}]}]}`)
+	parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), PlatformAnthropic)
+	require.NoError(t, err)
+
+	// 未向客户端写出任何字节前的读错误会包成 UpstreamFailoverError 走换号重试。
+	// 该路径必须保持 result=nil：failover 成功后按成功请求计费，双份结果会重复计费。
+	upstream := &anthropicHTTPUpstreamRecorder{resp: &http.Response{
+		StatusCode: http.StatusOK,
+		Header:     http.Header{"Content-Type": []string{"text/event-stream"}},
+		Body: &streamReadCloser{
+			err: errors.New("connection reset by peer"),
+		},
+	}}
+	svc := newForwardPartialUsageServiceForTest(upstream)
+	account := newAnthropicOAuthAccountForPartialUsageTest()
+
+	result, err := svc.Forward(context.Background(), c, account, parsed)
+	require.Error(t, err)
+	var failoverErr *UpstreamFailoverError
+	require.True(t, errors.As(err, &failoverErr))
+	require.Nil(t, result, "failover 错误必须保持 result=nil，防止重试成功后双重计费")
+}
+
+func TestGatewayService_Forward_PreOutputSSEOverloadedErrorUsesSemantic529(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/messages", nil)
+
+	body := []byte(`{"model":"claude-3-5-sonnet-latest","stream":true,"messages":[{"role":"user","content":"hello"}]}`)
+	parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), PlatformAnthropic)
+	require.NoError(t, err)
+
+	const errorJSON = `{"type":"error","error":{"details":null,"type":"overloaded_error","message":"Overloaded"},"request_id":"req_01"}`
+	upstream := &anthropicHTTPUpstreamRecorder{resp: &http.Response{
+		StatusCode: http.StatusOK,
+		Header:     http.Header{"Content-Type": []string{"text/event-stream"}},
+		Body:       io.NopCloser(strings.NewReader("event: error\ndata: " + errorJSON + "\n\n")),
+	}}
+	repo := &gatewayForwardErrorPolicyRepoStub{}
+	cfg := &config.Config{Gateway: config.GatewayConfig{MaxLineSize: defaultMaxLineSize}}
+	svc := &GatewayService{
+		cfg:                  cfg,
+		responseHeaderFilter: compileResponseHeaderFilter(cfg),
+		httpUpstream:         upstream,
+		rateLimitService:     NewRateLimitService(repo, nil, cfg, nil, nil),
+		deferredService:      &DeferredService{},
+	}
+	account := newAnthropicOAuthAccountForPartialUsageTest()
+	account.Credentials["temp_unschedulable_enabled"] = true
+	account.Credentials["temp_unschedulable_rules"] = []any{map[string]any{
+		"error_code":       float64(529),
+		"keywords":         []any{"Overloaded"},
+		"duration_minutes": float64(10),
+	}}
+
+	result, err := svc.Forward(context.Background(), c, account, parsed)
+	require.Error(t, err)
+	require.Nil(t, result)
+
+	var failoverErr *UpstreamFailoverError
+	require.ErrorAs(t, err, &failoverErr)
+	require.Equal(t, 529, failoverErr.StatusCode)
+	require.JSONEq(t, errorJSON, string(failoverErr.ResponseBody))
+	require.Len(t, repo.modelRateLimitCalls, 1, "synthetic 529 must participate in temp-unschedulable rules")
+	require.Equal(t, account.ID, repo.modelRateLimitCalls[0].accountID)
+	require.Equal(t, parsed.Model, repo.modelRateLimitCalls[0].scope)
+	require.Empty(t, rec.Body.String(), "pre-output overload must remain eligible for account failover")
+}
+
+func TestGatewayService_Forward_PostOutputSSEOverloadedErrorKeepsExistingStatus(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/messages", nil)
+
+	body := []byte(`{"model":"claude-3-5-sonnet-latest","stream":true,"messages":[{"role":"user","content":"hello"}]}`)
+	parsed, err := ParseGatewayRequest(NewRequestBodyRef(body), PlatformAnthropic)
+	require.NoError(t, err)
+
+	const errorJSON = `{"type":"error","error":{"type":"overloaded_error","message":"Overloaded"}}`
+	fixture := "event: message_start\ndata: {\"type\":\"message_start\",\"message\":{\"usage\":{\"input_tokens\":1}}}\n\n" +
+		"event: error\ndata: " + errorJSON + "\n\n"
+	upstream := &anthropicHTTPUpstreamRecorder{resp: &http.Response{
+		StatusCode: http.StatusOK,
+		Header:     http.Header{"Content-Type": []string{"text/event-stream"}},
+		Body:       io.NopCloser(strings.NewReader(fixture)),
+	}}
+	repo := &gatewayForwardErrorPolicyRepoStub{}
+	cfg := &config.Config{Gateway: config.GatewayConfig{MaxLineSize: defaultMaxLineSize}}
+	svc := &GatewayService{
+		cfg:                  cfg,
+		responseHeaderFilter: compileResponseHeaderFilter(cfg),
+		httpUpstream:         upstream,
+		rateLimitService:     NewRateLimitService(repo, nil, cfg, nil, nil),
+		deferredService:      &DeferredService{},
+	}
+
+	result, err := svc.Forward(context.Background(), c, newAnthropicOAuthAccountForPartialUsageTest(), parsed)
+	require.Error(t, err)
+	require.Nil(t, result)
+
+	var failoverErr *UpstreamFailoverError
+	require.ErrorAs(t, err, &failoverErr)
+	require.Equal(t, http.StatusForbidden, failoverErr.StatusCode)
+	require.JSONEq(t, errorJSON, string(failoverErr.ResponseBody))
+	require.Zero(t, repo.tempCalls)
+	require.Contains(t, rec.Body.String(), "message_start")
+}
+
+func TestGatewayService_AnthropicAPIKeyPassthrough_ForwardStreamMissingTerminalPreservesPartialUsage(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/messages", nil)
+
+	body := []byte(`{"model":"claude-3-7-sonnet-20250219","stream":true,"messages":[{"role":"user","content":[{"type":"text","text":"hello"}]}]}`)
+	parsed := &ParsedRequest{
+		Body:   NewRequestBodyRef(body),
+		Model:  "claude-3-7-sonnet-20250219",
+		Stream: true,
+	}
+
+	upstreamSSE := strings.Join([]string{
+		`data: {"type":"message_start","message":{"usage":{"input_tokens":9,"cache_read_input_tokens":2}}}`,
+		"",
+		`data: {"type":"message_delta","usage":{"output_tokens":3}}`,
+		"",
+	}, "\n")
+	upstream := &anthropicHTTPUpstreamRecorder{resp: &http.Response{
+		StatusCode: http.StatusOK,
+		Header: http.Header{
+			"Content-Type": []string{"text/event-stream"},
+			"X-Request-Id": []string{"rid-pass-partial"},
+		},
+		Body: io.NopCloser(strings.NewReader(upstreamSSE)),
+	}}
+	svc := newForwardPartialUsageServiceForTest(upstream)
+	account := newAnthropicAPIKeyAccountForTest()
+
+	result, err := svc.Forward(context.Background(), c, account, parsed)
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "missing terminal event")
+	require.NotNil(t, result, "透传流中断但已观测到 usage 时必须返回部分结果用于计费")
+	require.True(t, result.Stream)
+	require.Equal(t, 9, result.Usage.InputTokens)
+	require.Equal(t, 2, result.Usage.CacheReadInputTokens)
+	require.Equal(t, 3, result.Usage.OutputTokens)
+	require.Equal(t, "claude-3-7-sonnet-20250219", result.Model)
+}