Split simulator.go into several files (#199)

* Split simulator.go into several files

Signed-off-by: Ira <[email protected]>

* Tests reorganization

Signed-off-by: Ira <[email protected]>

* Lint

Signed-off-by: Ira <[email protected]>

* Lint

Signed-off-by: Ira <[email protected]>

* Test helper functiona and function renaming

Signed-off-by: Ira <[email protected]>

* Lint

Signed-off-by: Ira <[email protected]>

---------

Signed-off-by: Ira <[email protected]>

Author: irar2

pkg/llm-d-inference-sim/failures_test.go

@@ -26,7 +26,6 @@ import (
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
 	"github.com/openai/openai-go"
-	"github.com/openai/openai-go/option"
 
 	"github.com/llm-d/llm-d-inference-sim/pkg/common"
 	openaiserverapi "github.com/llm-d/llm-d-inference-sim/pkg/openai-server-api"
@@ -135,18 +134,8 @@ var _ = Describe("Failures", func() {
 			})
 
 			It("should always return an error response for chat completions", func() {
-				openaiClient := openai.NewClient(
-					option.WithBaseURL(baseURL),
-					option.WithHTTPClient(client),
-				)
-
-				_, err := openaiClient.Chat.Completions.New(ctx, openai.ChatCompletionNewParams{
-					Model: model,
-					Messages: []openai.ChatCompletionMessageParamUnion{
-						openai.UserMessage(userMessage),
-					},
-				})
-
+				openaiClient, params := getOpenAIClentAndChatParams(client, model, userMessage, false)
+				_, err := openaiClient.Chat.Completions.New(ctx, params)
 				Expect(err).To(HaveOccurred())
 
 				var openaiError *openai.Error
@@ -158,18 +147,8 @@ var _ = Describe("Failures", func() {
 			})
 
 			It("should always return an error response for text completions", func() {
-				openaiClient := openai.NewClient(
-					option.WithBaseURL(baseURL),
-					option.WithHTTPClient(client),
-				)
-
-				_, err := openaiClient.Completions.New(ctx, openai.CompletionNewParams{
-					Model: openai.CompletionNewParamsModel(model),
-					Prompt: openai.CompletionNewParamsPromptUnion{
-						OfString: openai.String(userMessage),
-					},
-				})
-
+				openaiClient, params := getOpenAIClentAndChatParams(client, model, userMessage, false)
+				_, err := openaiClient.Chat.Completions.New(ctx, params)
 				Expect(err).To(HaveOccurred())
 
 				var openaiError *openai.Error
@@ -194,18 +173,8 @@ var _ = Describe("Failures", func() {
 			})
 
 			It("should return only rate limit errors", func() {
-				openaiClient := openai.NewClient(
-					option.WithBaseURL(baseURL),
-					option.WithHTTPClient(client),
-				)
-
-				_, err := openaiClient.Chat.Completions.New(ctx, openai.ChatCompletionNewParams{
-					Model: model,
-					Messages: []openai.ChatCompletionMessageParamUnion{
-						openai.UserMessage(userMessage),
-					},
-				})
-
+				openaiClient, params := getOpenAIClentAndChatParams(client, model, userMessage, false)
+				_, err := openaiClient.Chat.Completions.New(ctx, params)
 				Expect(err).To(HaveOccurred())
 
 				var openaiError *openai.Error
@@ -230,20 +199,11 @@ var _ = Describe("Failures", func() {
 			})
 
 			It("should return only specified error types", func() {
-				openaiClient := openai.NewClient(
-					option.WithBaseURL(baseURL),
-					option.WithHTTPClient(client),
-				)
+				openaiClient, params := getOpenAIClentAndChatParams(client, model, userMessage, false)
 
 				// Make multiple requests to verify we get the expected error types
 				for i := 0; i < 10; i++ {
-					_, err := openaiClient.Chat.Completions.New(ctx, openai.ChatCompletionNewParams{
-						Model: model,
-						Messages: []openai.ChatCompletionMessageParamUnion{
-							openai.UserMessage(userMessage),
-						},
-					})
-
+					_, err := openaiClient.Chat.Completions.New(ctx, params)
 					Expect(err).To(HaveOccurred())
 
 					var openaiError *openai.Error
@@ -270,18 +230,8 @@ var _ = Describe("Failures", func() {
 			})
 
 			It("should never return errors and behave like random mode", func() {
-				openaiClient := openai.NewClient(
-					option.WithBaseURL(baseURL),
-					option.WithHTTPClient(client),
-				)
-
-				resp, err := openaiClient.Chat.Completions.New(ctx, openai.ChatCompletionNewParams{
-					Model: model,
-					Messages: []openai.ChatCompletionMessageParamUnion{
-						openai.UserMessage(userMessage),
-					},
-				})
-
+				openaiClient, params := getOpenAIClentAndChatParams(client, model, userMessage, false)
+				resp, err := openaiClient.Chat.Completions.New(ctx, params)
 				Expect(err).ToNot(HaveOccurred())
 				Expect(resp.Choices).To(HaveLen(1))
 				Expect(resp.Choices[0].Message.Content).ToNot(BeEmpty())
@@ -300,18 +250,8 @@ var _ = Describe("Failures", func() {
 					}, nil)
 					Expect(err).ToNot(HaveOccurred())
 
-					openaiClient := openai.NewClient(
-						option.WithBaseURL(baseURL),
-						option.WithHTTPClient(client),
-					)
-
-					_, err = openaiClient.Chat.Completions.New(ctx, openai.ChatCompletionNewParams{
-						Model: model,
-						Messages: []openai.ChatCompletionMessageParamUnion{
-							openai.UserMessage(userMessage),
-						},
-					})
-
+					openaiClient, params := getOpenAIClentAndChatParams(client, model, userMessage, false)
+					_, err = openaiClient.Chat.Completions.New(ctx, params)
 					Expect(err).To(HaveOccurred())
 
 					var openaiError *openai.Error

pkg/llm-d-inference-sim/helpers.go

@@ -0,0 +1,94 @@
+/*
+Copyright 2025 The llm-d-inference-sim Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package vllmsim implements the vLLM simulator.
+package llmdinferencesim
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+// isValidModel checks if the given model is the base model or one of "loaded" LoRAs
+func (s *VllmSimulator) isValidModel(model string) bool {
+	for _, name := range s.config.ServedModelNames {
+		if model == name {
+			return true
+		}
+	}
+	for _, lora := range s.getLoras() {
+		if model == lora {
+			return true
+		}
+	}
+
+	return false
+}
+
+// isLora returns true if the given model name is one of loaded LoRAs
+func (s *VllmSimulator) isLora(model string) bool {
+	for _, lora := range s.getLoras() {
+		if model == lora {
+			return true
+		}
+	}
+
+	return false
+}
+
+// getDisplayedModelName returns the model name that must appear in API
+// responses.  LoRA adapters keep their explicit name, while all base-model
+// requests are surfaced as the first alias from --served-model-name.
+func (s *VllmSimulator) getDisplayedModelName(reqModel string) string {
+	if s.isLora(reqModel) {
+		return reqModel
+	}
+	return s.config.ServedModelNames[0]
+}
+
+func (s *VllmSimulator) showConfig(dp bool) error {
+	cfgJSON, err := json.Marshal(s.config)
+	if err != nil {
+		return fmt.Errorf("failed to marshal configuration to JSON: %w", err)
+	}
+
+	var m map[string]interface{}
+	err = json.Unmarshal(cfgJSON, &m)
+	if err != nil {
+		return fmt.Errorf("failed to unmarshal JSON to map: %w", err)
+	}
+	if dp {
+		// remove the port
+		delete(m, "port")
+	}
+	// clean LoraModulesString field
+	m["lora-modules"] = m["LoraModules"]
+	delete(m, "LoraModules")
+	delete(m, "LoraModulesString")
+
+	// clean fake-metrics field
+	if field, ok := m["fake-metrics"].(map[string]interface{}); ok {
+		delete(field, "LorasString")
+	}
+
+	// show in JSON
+	cfgJSON, err = json.MarshalIndent(m, "", "  ")
+	if err != nil {
+		return fmt.Errorf("failed to marshal configuration to JSON: %w", err)
+	}
+	s.logger.Info("Configuration:", "", string(cfgJSON))
+	return nil
+}

pkg/llm-d-inference-sim/latencies.go

@@ -0,0 +1,65 @@
+/*
+Copyright 2025 The llm-d-inference-sim Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package vllmsim implements the vLLM simulator.
+package llmdinferencesim
+
+import "github.com/llm-d/llm-d-inference-sim/pkg/common"
+
+func (s *VllmSimulator) getCurrLoadFactor() float64 {
+	if s.config.MaxNumSeqs <= 1 {
+		return 1.0
+	}
+	return 1 + (s.config.TimeFactorUnderLoad-1)*float64(s.nRunningReqs-1)/float64(s.config.MaxNumSeqs-1)
+}
+
+func (s *VllmSimulator) getTimeToFirstToken() int {
+	return int(float64(s.config.TimeToFirstToken) * s.getCurrLoadFactor())
+}
+
+func (s *VllmSimulator) getPrefillOverhead() int {
+	return int(float64(s.config.PrefillOverhead) * s.getCurrLoadFactor())
+}
+
+func (s *VllmSimulator) getPrefillTimePerToken() int {
+	return int(float64(s.config.PrefillTimePerToken) * s.getCurrLoadFactor())
+}
+
+// returns time to first token based on the current request's doRemotePrefill
+func (s *VllmSimulator) getWaitTimeToFirstToken(nPromptTokens int, nCachedPromptTokens int, doRemotePrefill bool) int {
+	if doRemotePrefill {
+		if s.config.KVCacheTransferLatency == 0 && s.config.KVCacheTransferLatencyStdDev == 0 {
+			// is disaggregated PD and ttft is calculated using number of prompt tokens
+			kvCacheTransT := s.config.KVCacheTransferTimePerToken * nPromptTokens
+			return common.RandomNorm(kvCacheTransT, s.config.KVCacheTransferTimeStdDev)
+		}
+		// is disaggregated PD and *not* using number of prompt tokens
+		return common.RandomNorm(s.config.KVCacheTransferLatency, s.config.KVCacheTransferLatencyStdDev)
+	}
+	if s.config.TimeToFirstToken == 0 && s.config.TimeToFirstTokenStdDev == 0 {
+		// is aggregated PD and ttft is calculated using number of prompt tokens that are not in kv cache
+		prefillTime := s.getPrefillOverhead() + (nPromptTokens-nCachedPromptTokens)*s.getPrefillTimePerToken()
+		return common.RandomNorm(prefillTime, s.config.PrefillTimeStdDev)
+	}
+	// is aggregated PD and *not* using number of prompt tokens
+	return common.RandomNorm(s.getTimeToFirstToken(), s.config.TimeToFirstTokenStdDev)
+}
+
+// returns inter token latency
+func (s *VllmSimulator) getInterTokenLatency() int {
+	latency := int(float64(s.config.InterTokenLatency) * s.getCurrLoadFactor())
+	return common.RandomNorm(latency, s.config.InterTokenLatencyStdDev)
+}