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sub2api/backend/internal/handler/openai_chat_completions.go
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Sub2API v1.0 - AI API 网关(二开初始版本,基于上游 Wei-Shaw/sub2api)
2026-08-21 18:30:13 +08:00

423 lines
16 KiB
Go

package handler
import (
"context"
"errors"
"net/http"
"strconv"
"strings"
"time"
"github.com/Wei-Shaw/sub2api/internal/pkg/ip"
"github.com/Wei-Shaw/sub2api/internal/pkg/logger"
"github.com/Wei-Shaw/sub2api/internal/pkg/openai_compat"
middleware2 "github.com/Wei-Shaw/sub2api/internal/server/middleware"
"github.com/Wei-Shaw/sub2api/internal/service"
"github.com/gin-gonic/gin"
"github.com/tidwall/gjson"
"go.uber.org/zap"
)
// ChatCompletions handles OpenAI Chat Completions API requests.
// POST /v1/chat/completions
func (h *OpenAIGatewayHandler) ChatCompletions(c *gin.Context) {
streamStarted := false
defer h.recoverResponsesPanic(c, &streamStarted)
requestStart := time.Now()
apiKey, ok := middleware2.GetAPIKeyFromContext(c)
if !ok {
h.errorResponse(c, http.StatusUnauthorized, "authentication_error", "Invalid API key")
return
}
subject, ok := middleware2.GetAuthSubjectFromContext(c)
if !ok {
h.errorResponse(c, http.StatusInternalServerError, "api_error", "User context not found")
return
}
reqLog := requestLogger(
c,
"handler.openai_gateway.chat_completions",
zap.Int64("user_id", subject.UserID),
zap.Int64("api_key_id", apiKey.ID),
zap.Any("group_id", apiKey.GroupID),
)
if !h.ensureResponsesDependencies(c, reqLog) {
return
}
body, err := readLenientJSONRequestBodyWithPrealloc(c.Request, h.cfg)
if err != nil {
if maxErr, ok := extractMaxBytesError(err); ok {
h.errorResponse(c, http.StatusRequestEntityTooLarge, "invalid_request_error", buildBodyTooLargeMessage(maxErr.Limit))
return
}
h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "Failed to read request body")
return
}
if len(body) == 0 {
h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "Request body is empty")
return
}
if !gjson.ValidBytes(body) {
logRequestBodyParseFailure(reqLog, body, nil)
h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "Failed to parse request body")
return
}
modelResult := gjson.GetBytes(body, "model")
if !modelResult.Exists() || modelResult.Type != gjson.String || modelResult.String() == "" {
h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "model is required")
return
}
reqModel := modelResult.String()
ensureCompositeTargetPlatform(c, apiKey, reqModel)
if !openAICompatibleTextTargetAllowed(c, apiKey, reqModel) {
h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "Model is not supported by this OpenAI-compatible endpoint for composite groups")
return
}
if cappedBody, changed := applyOpenAIReasoningEffortPolicyForRequest(c, apiKey, body); changed {
body = cappedBody
}
reqStream, ok := parseOpenAICompatibleStream(body)
if !ok {
h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", invalidStreamFieldTypeMessage)
return
}
if service.IsGPTImageGenerationModel(reqModel) {
h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "This model is not supported on the Chat Completions endpoint")
return
}
reqLog = reqLog.With(zap.String("model", reqModel), zap.Bool("stream", reqStream))
setOpsRequestContext(c, reqModel, reqStream)
setOpsEndpointContext(c, "", int16(service.RequestTypeFromLegacy(reqStream, false)))
if decision := h.checkSecurityAudit(c, reqLog, apiKey, subject, service.ContentModerationProtocolOpenAIChat, reqModel, body); decision != nil && !decision.AllowNextStage {
h.openAISecurityAuditError(c, decision)
return
}
if h.rejectIfCyberSessionBlocked(c, apiKey, body, reqModel, cyberBlockFormatChat) {
return
}
// 解析渠道级模型映射
channelMapping, _ := h.gatewayService.ResolveChannelMappingAndRestrict(c.Request.Context(), apiKey.GroupID, reqModel)
if h.errorPassthroughService != nil {
service.BindErrorPassthroughService(c, h.errorPassthroughService)
}
subscription, _ := middleware2.GetSubscriptionFromContext(c)
requestPlatform := openAICompatibleRequestPlatform(c.Request.Context(), apiKey)
service.SetOpsLatencyMs(c, service.OpsAuthLatencyMsKey, time.Since(requestStart).Milliseconds())
routingStart := time.Now()
userReleaseFunc, acquired := h.acquireResponsesUserSlot(c, subject.UserID, subject.Concurrency, reqStream, &streamStarted, reqLog)
if !acquired {
return
}
if userReleaseFunc != nil {
defer userReleaseFunc()
}
if err := h.billingCacheService.CheckBillingEligibility(c.Request.Context(), apiKey.User, apiKey, apiKey.Group, subscription, service.QuotaPlatform(c.Request.Context(), apiKey)); err != nil {
reqLog.Info("openai_chat_completions.billing_eligibility_check_failed", zap.Error(err))
status, code, message, retryAfter := billingErrorDetails(err)
if retryAfter > 0 {
c.Header("Retry-After", strconv.Itoa(retryAfter))
}
h.handleStreamingAwareError(c, status, code, message, streamStarted)
return
}
sessionHash := h.gatewayService.GenerateSessionHash(c, body)
promptCacheKey := h.gatewayService.ExtractSessionID(c, body)
maxAccountSwitches := h.maxAccountSwitches
switchCount := 0
profitVetoCount := 0
failedAccountIDs := make(map[int64]struct{})
sameAccountRetryCount := make(map[int64]int)
var lastFailoverErr *service.UpstreamFailoverError
var oauth429FailoverState service.OpenAIOAuth429FailoverState
// 分组利润控制:chat completions 文本入口请求级装门并固定 pricingAt。
ccPricingCtx, pricingAt := h.gatewayService.WithOpenAIRequestPricingContext(c.Request.Context(), apiKey.GroupID)
c.Request = c.Request.WithContext(ccPricingCtx)
for {
if failoverClientGone(c) {
return
}
reqLog.Debug("openai_chat_completions.account_selecting", zap.Int("excluded_account_count", len(failedAccountIDs)))
selection, scheduleDecision, err := h.gatewayService.SelectAccountWithSchedulerForCapability(
c.Request.Context(),
apiKey.GroupID,
"",
sessionHash,
reqModel,
failedAccountIDs,
service.OpenAIUpstreamTransportAny,
service.OpenAIEndpointCapabilityChatCompletions,
false,
false,
true,
requestPlatform,
)
if err != nil {
if failoverClientGone(c) {
reqLog.Info("openai_chat_completions.account_select_aborted_client_disconnected", zap.Error(err))
return
}
reqLog.Warn("openai_chat_completions.account_select_failed",
zap.Error(openAICompatibleSelectionErrorForLog(err, requestPlatform)),
zap.Int("excluded_account_count", len(failedAccountIDs)),
)
if len(failedAccountIDs) == 0 {
cls := classifyOpenAICompatibleNoAccountErrorFromGin(c, h.gatewayService, apiKey, reqModel, reqModel)
if !cls.ModelNotFound {
markOpsRoutingCapacityLimitedIfNoAvailable(c, err)
}
h.handleStreamingAwareError(c, cls.Status, cls.ErrType, cls.Message, streamStarted)
return
} else {
if lastFailoverErr != nil {
h.handleFailoverExhausted(c, lastFailoverErr, streamStarted)
} else {
h.handleStreamingAwareError(c, http.StatusBadGateway, "api_error", "Upstream request failed", streamStarted)
}
return
}
}
if selection == nil || selection.Account == nil {
cls := classifyOpenAICompatibleNoAccountErrorFromGin(c, h.gatewayService, apiKey, reqModel, reqModel)
if !cls.ModelNotFound {
markOpsRoutingCapacityLimited(c)
}
h.handleStreamingAwareError(c, cls.Status, cls.ErrType, cls.Message, streamStarted)
return
}
account := selection.Account
sessionHash = ensureOpenAIPoolModeSessionHash(sessionHash, account)
reqLog.Debug("openai_chat_completions.account_selected", zap.Int64("account_id", account.ID), zap.String("account_name", account.Name))
_ = scheduleDecision
setOpsSelectedAccount(c, account.ID, account.Platform)
accountReleaseFunc, slotResult := h.acquireResponsesAccountSlot(c, apiKey.GroupID, sessionHash, selection, reqStream, &streamStarted, reqLog)
if slotResult == openAISlotAcquireProfitVetoed {
// 利润终检否决:排除该账号重新选号;否决次数达上限则按无可用账号终止。
if !recordOpenAIProfitVeto(failedAccountIDs, account.ID, &profitVetoCount) {
h.handleOpenAIProfitVetoExhausted(c, streamStarted, reqLog, profitVetoCount)
return
}
continue
}
if slotResult != openAISlotAcquireOK {
return
}
service.SetOpsLatencyMs(c, service.OpsRoutingLatencyMsKey, time.Since(routingStart).Milliseconds())
forwardStart := time.Now()
forwardBody := body
if channelMapping.Mapped {
forwardBody = h.gatewayService.ReplaceModelInBody(body, channelMapping.MappedModel)
}
writerSizeBeforeForward := c.Writer.Size()
result, err := func() (*service.OpenAIForwardResult, error) {
defer func() {
if accountReleaseFunc != nil {
accountReleaseFunc()
}
}()
return h.gatewayService.ForwardAsChatCompletions(c.Request.Context(), c, account, forwardBody, promptCacheKey, "")
}()
cyberBlockKeyChat := ""
if service.GetOpsCyberPolicy(c) != nil {
cyberBlockKeyChat = service.CyberSessionBlockKey(apiKey.ID, c, body)
}
h.recordCyberPolicyIfMarked(c, apiKey, account, subscription, reqModel, err != nil, cyberBlockKeyChat, clientRequestedUsageFields(c, channelMapping, reqModel, ""), service.HashUsageRequestPayload(body))
forwardDurationMs := time.Since(forwardStart).Milliseconds()
upstreamLatencyMs, _ := getContextInt64(c, service.OpsUpstreamLatencyMsKey)
responseLatencyMs := forwardDurationMs
if upstreamLatencyMs > 0 && forwardDurationMs > upstreamLatencyMs {
responseLatencyMs = forwardDurationMs - upstreamLatencyMs
}
service.SetOpsLatencyMs(c, service.OpsResponseLatencyMsKey, responseLatencyMs)
if err == nil && result != nil && result.FirstTokenMs != nil {
service.SetOpsLatencyMs(c, service.OpsTimeToFirstTokenMsKey, int64(*result.FirstTokenMs))
}
// #5148 对齐:错误返回携带的部分 result(流中断前上游已计量的 usage)照常
// 入账;failover 错误恒定 result=nil,不会重复计费。
submitChatUsage := func(res *service.OpenAIForwardResult) {
if res == nil {
return
}
userAgent := c.GetHeader("User-Agent")
clientIP := ip.GetClientIP(c)
inboundEndpoint := GetInboundEndpoint(c)
upstreamEndpoint := resolveOpenAIUpstreamEndpoint(c, account, res)
quotaPlatform := service.QuotaPlatform(c.Request.Context(), apiKey)
sessionID := service.ExtractClientSessionID(c)
cyberBlocked := service.GetOpsCyberPolicy(c) != nil
h.submitOpenAIUsageRecordTask(c.Request.Context(), res, func(ctx context.Context) {
if err := h.gatewayService.RecordUsage(ctx, &service.OpenAIRecordUsageInput{
Result: res,
APIKey: apiKey,
User: apiKey.User,
Account: account,
Subscription: subscription,
InboundEndpoint: inboundEndpoint,
UpstreamEndpoint: upstreamEndpoint,
UserAgent: userAgent,
IPAddress: clientIP,
APIKeyService: h.apiKeyService,
QuotaPlatform: quotaPlatform,
SessionID: sessionID,
ChannelUsageFields: clientRequestedUsageFields(c, channelMapping, reqModel, res.UpstreamModel),
PricingAt: pricingAt,
CyberBlocked: cyberBlocked,
}); err != nil {
logger.L().With(
zap.String("component", "handler.openai_gateway.chat_completions"),
zap.Int64("user_id", subject.UserID),
zap.Int64("api_key_id", apiKey.ID),
zap.Any("group_id", apiKey.GroupID),
zap.String("model", reqModel),
zap.Int64("account_id", account.ID),
).Error("openai_chat_completions.record_usage_failed", zap.Error(err))
}
})
}
if err != nil {
if result != nil && result.ImageCount > 0 {
reqLog.Warn("openai_chat_completions.forward_partial_error_with_image_result",
zap.Int64("account_id", account.ID),
zap.Int("image_count", result.ImageCount),
zap.Error(err),
)
} else {
var failoverErr *service.UpstreamFailoverError
if errors.As(err, &failoverErr) {
if failoverClientGone(c) {
reqLog.Info("openai_chat_completions.failover_aborted_client_disconnected",
zap.Int64("account_id", account.ID),
zap.Int("upstream_status", failoverErr.StatusCode),
)
return
}
if c.Writer.Size() != writerSizeBeforeForward {
h.handleFailoverExhausted(c, failoverErr, true)
return
}
if failoverErr.ShouldReportAccountScheduleFailure() {
h.gatewayService.ReportOpenAIAccountScheduleResult(account.ID, account.GetMappedModel(reqModel), false, nil)
}
if !failoverErr.ShouldRetryNextAccount() {
h.handleFailoverExhausted(c, failoverErr, streamStarted)
return
}
// Pool mode: retry on the same account
if failoverErr.RetryableOnSameAccount {
retryLimit := account.GetPoolModeRetryCount()
if sameAccountRetryCount[account.ID] < retryLimit {
sameAccountRetryCount[account.ID]++
retryDelay := sameAccountRetryDelayFor(failoverErr, sameAccountRetryCount[account.ID])
reqLog.Warn("openai_chat_completions.pool_mode_same_account_retry",
zap.Int64("account_id", account.ID),
zap.Int("upstream_status", failoverErr.StatusCode),
zap.Int("retry_limit", retryLimit),
zap.Int("retry_count", sameAccountRetryCount[account.ID]),
zap.Duration("retry_delay", retryDelay),
)
select {
case <-c.Request.Context().Done():
return
case <-time.After(retryDelay):
}
continue
}
}
h.gatewayService.RecordOpenAIAccountSwitch()
failedAccountIDs[account.ID] = struct{}{}
lastFailoverErr = failoverErr
if switchCount >= maxAccountSwitches {
h.handleFailoverExhausted(c, failoverErr, streamStarted)
return
}
switchCount++
if h.gatewayService.ShouldStopOpenAIOAuth429Failover(account, failoverErr.StatusCode, switchCount, &oauth429FailoverState) {
h.handleFailoverExhausted(c, failoverErr, streamStarted)
return
}
reqLog.Warn("openai_chat_completions.upstream_failover_switching",
zap.Int64("account_id", account.ID),
zap.Int("upstream_status", failoverErr.StatusCode),
zap.Int("switch_count", switchCount),
zap.Int("max_switches", maxAccountSwitches),
)
continue
}
h.gatewayService.ReportOpenAIAccountScheduleResult(account.ID, account.GetMappedModel(reqModel), false, nil)
upstreamErrorAlreadyCommunicated := openAIForwardErrorAlreadyCommunicated(c, writerSizeBeforeForward, err)
wroteFallback := false
if !upstreamErrorAlreadyCommunicated {
wroteFallback = h.ensureOpenAIStreamReadErrorResponse(c, err, streamStarted)
if !wroteFallback {
wroteFallback = h.ensureForwardErrorResponse(c, streamStarted)
}
}
reqLog.Warn("openai_chat_completions.forward_failed",
zap.Int64("account_id", account.ID),
zap.Bool("fallback_error_response_written", wroteFallback),
zap.Bool("upstream_error_response_already_written", upstreamErrorAlreadyCommunicated),
zap.Error(err),
)
submitChatUsage(result)
return
}
}
if result != nil {
h.gatewayService.ReportOpenAIAccountScheduleResult(account.ID, account.GetMappedModel(reqModel), true, result.FirstTokenMs)
} else {
h.gatewayService.ReportOpenAIAccountScheduleResult(account.ID, account.GetMappedModel(reqModel), true, nil)
}
submitChatUsage(result)
reqLog.Debug("openai_chat_completions.request_completed",
zap.Int64("account_id", account.ID),
zap.Int("switch_count", switchCount),
)
return
}
}
// resolveOpenAIUpstreamEndpoint returns the actual upstream endpoint for an
// OpenAI-compatible account. A forwarding result is authoritative because a
// single inbound route may choose raw Chat or a Responses bridge at runtime.
// The account-based derivation remains as a fallback for existing callers and
// forwarding paths that do not report their endpoint yet.
func resolveOpenAIUpstreamEndpoint(c *gin.Context, account *service.Account, result *service.OpenAIForwardResult) string {
if result != nil {
if endpoint := strings.TrimSpace(result.UpstreamEndpoint); endpoint != "" {
return endpoint
}
}
if endpoint := service.GetActualOpenAIUpstreamEndpoint(c); endpoint != "" {
return endpoint
}
if account != nil && account.Type == service.AccountTypeAPIKey &&
!openai_compat.ShouldUseResponsesAPI(account.Extra) {
return EndpointChatCompletions
}
return GetUpstreamEndpoint(c, account.Platform)
}