feat: implement tiered billing expression evaluation and related functionality

- Added support for tiered billing expressions in the billing system.
- Introduced new types and functions for handling billing expressions, including caching and execution.
- Updated existing billing logic to accommodate tiered billing scenarios.
- Enhanced request handling to support incoming billing expression requests.
- Added tests for tiered billing functionality to ensure correctness.

relay/helper/billing_expr_request.go

@@ -0,0 +1,54 @@
+package helper
+
+import (
+	"strings"
+
+	"github.com/QuantumNous/new-api/common"
+	"github.com/QuantumNous/new-api/pkg/billingexpr"
+	relaycommon "github.com/QuantumNous/new-api/relay/common"
+	"github.com/gin-gonic/gin"
+)
+
+func ResolveIncomingBillingExprRequestInput(c *gin.Context, info *relaycommon.RelayInfo) (billingexpr.RequestInput, error) {
+	input := billingexpr.RequestInput{}
+	if info != nil {
+		input.Headers = cloneStringMap(info.RequestHeaders)
+	}
+
+	bodyBytes, err := readIncomingBillingExprBody(c)
+	if err != nil {
+		return billingexpr.RequestInput{}, err
+	}
+	input.Body = bodyBytes
+	return input, nil
+}
+
+func readIncomingBillingExprBody(c *gin.Context) ([]byte, error) {
+	if c == nil || c.Request == nil || !isJSONContentType(c.Request.Header.Get("Content-Type")) {
+		return nil, nil
+	}
+	storage, err := common.GetBodyStorage(c)
+	if err != nil {
+		return nil, err
+	}
+	return storage.Bytes()
+}
+
+func isJSONContentType(contentType string) bool {
+	contentType = strings.ToLower(strings.TrimSpace(contentType))
+	return strings.HasPrefix(contentType, "application/json")
+}
+
+func cloneStringMap(src map[string]string) map[string]string {
+	if len(src) == 0 {
+		return map[string]string{}
+	}
+	dst := make(map[string]string, len(src))
+	for key, value := range src {
+		if strings.TrimSpace(key) == "" {
+			continue
+		}
+		dst[key] = value
+	}
+	return dst
+}

relay/helper/billing_expr_request_test.go

@@ -0,0 +1,35 @@
+package helper
+
+import (
+	"bytes"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/QuantumNous/new-api/common"
+	relaycommon "github.com/QuantumNous/new-api/relay/common"
+	"github.com/gin-gonic/gin"
+	"github.com/stretchr/testify/require"
+)
+
+func TestResolveIncomingBillingExprRequestInput(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	recorder := httptest.NewRecorder()
+	ctx, _ := gin.CreateTestContext(recorder)
+	ctx.Request = httptest.NewRequest(http.MethodPost, "/v1/chat/completions", nil)
+	ctx.Request.Header.Set("Content-Type", "application/json")
+
+	body := []byte(`{"service_tier":"fast"}`)
+	ctx.Request.Body = io.NopCloser(bytes.NewReader(body))
+	ctx.Set(common.KeyRequestBody, body)
+
+	info := &relaycommon.RelayInfo{
+		RequestHeaders: map[string]string{"Content-Type": "application/json"},
+	}
+
+	input, err := ResolveIncomingBillingExprRequestInput(ctx, info)
+	require.NoError(t, err)
+	require.Equal(t, body, input.Body)
+	require.Equal(t, "application/json", input.Headers["Content-Type"])
+}

relay/helper/price.go

@@ -5,7 +5,9 @@ import (
 
 	"github.com/QuantumNous/new-api/common"
 	"github.com/QuantumNous/new-api/logger"
+	"github.com/QuantumNous/new-api/pkg/billingexpr"
 	relaycommon "github.com/QuantumNous/new-api/relay/common"
+	"github.com/QuantumNous/new-api/setting/billing_setting"
 	"github.com/QuantumNous/new-api/setting/operation_setting"
 	"github.com/QuantumNous/new-api/setting/ratio_setting"
 	"github.com/QuantumNous/new-api/types"
@@ -50,6 +52,11 @@ func ModelPriceHelper(c *gin.Context, info *relaycommon.RelayInfo, promptTokens
 
 	groupRatioInfo := HandleGroupRatio(c, info)
 
+	// Check if this model uses tiered_expr billing
+	if billing_setting.GetBillingMode(info.OriginModelName) == billing_setting.BillingModeTieredExpr {
+		return modelPriceHelperTiered(c, info, promptTokens, meta, groupRatioInfo)
+	}
+
 	var preConsumedQuota int
 	var modelRatio float64
 	var completionRatio float64
@@ -195,5 +202,73 @@ func ContainPriceOrRatio(modelName string) bool {
 	if ok {
 		return true
 	}
+	if billing_setting.GetBillingMode(modelName) == billing_setting.BillingModeTieredExpr {
+		_, ok = billing_setting.GetBillingExpr(modelName)
+		return ok
+	}
 	return false
 }
+
+func modelPriceHelperTiered(c *gin.Context, info *relaycommon.RelayInfo, promptTokens int, meta *types.TokenCountMeta, groupRatioInfo types.GroupRatioInfo) (types.PriceData, error) {
+	exprStr, ok := billing_setting.GetBillingExpr(info.OriginModelName)
+	if !ok {
+		return types.PriceData{}, fmt.Errorf("model %s is configured as tiered_expr but has no billing expression", info.OriginModelName)
+	}
+
+	estimatedCompletionTokens := 0
+	if meta.MaxTokens != 0 {
+		estimatedCompletionTokens = meta.MaxTokens
+	}
+
+	requestInput, err := ResolveIncomingBillingExprRequestInput(c, info)
+	if err != nil {
+		return types.PriceData{}, err
+	}
+
+	rawQuota, trace, err := billingexpr.RunExprWithRequest(exprStr, billingexpr.TokenParams{
+		P: float64(promptTokens),
+		C: float64(estimatedCompletionTokens),
+	}, requestInput)
+	if err != nil {
+		return types.PriceData{}, fmt.Errorf("model %s tiered expr run failed: %w", info.OriginModelName, err)
+	}
+
+	preConsumedQuota := billingexpr.QuotaRound(rawQuota * groupRatioInfo.GroupRatio)
+
+	freeModel := false
+	if !operation_setting.GetQuotaSetting().EnableFreeModelPreConsume {
+		if groupRatioInfo.GroupRatio == 0 || rawQuota == 0 {
+			preConsumedQuota = 0
+			freeModel = true
+		}
+	}
+
+	exprHash := billingexpr.ExprHashString(exprStr)
+	snapshot := &billingexpr.BillingSnapshot{
+		BillingMode:               billing_setting.BillingModeTieredExpr,
+		ModelName:                 info.OriginModelName,
+		ExprString:                exprStr,
+		ExprHash:                  exprHash,
+		GroupRatio:                groupRatioInfo.GroupRatio,
+		EstimatedPromptTokens:     promptTokens,
+		EstimatedCompletionTokens: estimatedCompletionTokens,
+		EstimatedQuotaBeforeGroup: rawQuota,
+		EstimatedQuotaAfterGroup:  preConsumedQuota,
+		EstimatedTier:             trace.MatchedTier,
+	}
+	info.TieredBillingSnapshot = snapshot
+	info.BillingRequestInput = &requestInput
+
+	priceData := types.PriceData{
+		FreeModel:         freeModel,
+		GroupRatioInfo:    groupRatioInfo,
+		QuotaToPreConsume: preConsumedQuota,
+	}
+
+	if common.DebugEnabled {
+		println(fmt.Sprintf("model_price_helper_tiered result: model=%s preConsume=%d rawQuota=%.2f groupRatio=%.2f tier=%s", info.OriginModelName, preConsumedQuota, rawQuota, groupRatioInfo.GroupRatio, trace.MatchedTier))
+	}
+
+	info.PriceData = priceData
+	return priceData, nil
+}