feat: implement AI gateway phase one runtime

apps/api/internal/runner/limits.go

@@ -0,0 +1,89 @@
+package runner
+
+import (
+	"context"
+	"strings"
+
+	"github.com/easyai/easyai-ai-gateway/apps/api/internal/auth"
+	"github.com/easyai/easyai-ai-gateway/apps/api/internal/store"
+)
+
+func (s *Service) rateLimitReservations(ctx context.Context, user *auth.User, candidate store.RuntimeModelCandidate, body map[string]any) []store.RateLimitReservation {
+	out := make([]store.RateLimitReservation, 0)
+	out = append(out, reservationsFromPolicy("platform_model", candidate.PlatformModelID, effectiveRateLimitPolicy(candidate), body)...)
+	if group, err := s.store.ResolveUserGroupPolicy(ctx, user); err == nil && group.ID != "" {
+		out = append(out, reservationsFromPolicy("user_group", group.ID, group.RateLimitPolicy, body)...)
+	}
+	return out
+}
+
+func effectiveRateLimitPolicy(candidate store.RuntimeModelCandidate) map[string]any {
+	if hasRules(candidate.ModelRateLimitPolicy) {
+		return candidate.ModelRateLimitPolicy
+	}
+	if hasRules(candidate.PlatformRateLimitPolicy) {
+		return candidate.PlatformRateLimitPolicy
+	}
+	return nil
+}
+
+func reservationsFromPolicy(scopeType string, scopeKey string, policy map[string]any, body map[string]any) []store.RateLimitReservation {
+	if scopeKey == "" || !hasRules(policy) {
+		return nil
+	}
+	rules, _ := policy["rules"].([]any)
+	out := make([]store.RateLimitReservation, 0, len(rules))
+	estimatedTokens := estimateRequestTokens(body)
+	for _, rawRule := range rules {
+		rule, _ := rawRule.(map[string]any)
+		metric := strings.TrimSpace(stringFromMap(rule, "metric"))
+		limit := floatFromAny(rule["limit"])
+		amount := 1.0
+		if strings.HasPrefix(metric, "tpm") {
+			amount = float64(estimatedTokens)
+		}
+		out = append(out, store.RateLimitReservation{
+			ScopeType:       scopeType,
+			ScopeKey:        scopeKey,
+			Metric:          metric,
+			Limit:           limit,
+			Amount:          amount,
+			WindowSeconds:   int(floatFromAny(rule["windowSeconds"])),
+			LeaseTTLSeconds: int(floatFromAny(rule["leaseTtlSeconds"])),
+		})
+	}
+	return out
+}
+
+func hasRules(policy map[string]any) bool {
+	rules, _ := policy["rules"].([]any)
+	return len(rules) > 0
+}
+
+func estimateRequestTokens(body map[string]any) int {
+	text := ""
+	if prompt := stringFromMap(body, "prompt"); prompt != "" {
+		text += prompt
+	}
+	if input := stringFromMap(body, "input"); input != "" {
+		text += input
+	}
+	if messages, ok := body["messages"].([]any); ok {
+		for _, raw := range messages {
+			message, _ := raw.(map[string]any)
+			switch content := message["content"].(type) {
+			case string:
+				text += content
+			case []any:
+				for _, rawPart := range content {
+					part, _ := rawPart.(map[string]any)
+					text += stringFromMap(part, "text")
+				}
+			}
+		}
+	}
+	if text == "" {
+		return 1
+	}
+	return len([]rune(text))/4 + 1
+}