router.rs 29 KB
Newer Older
1
2
// gRPC Router Implementation

3
4
5
6
7
8
9
10
11
12
13
use std::sync::Arc;

use async_trait::async_trait;
use axum::{
    body::Body,
    extract::Request,
    http::{HeaderMap, StatusCode},
    response::{IntoResponse, Response},
};
use tracing::{debug, error, info, warn};

14
use crate::config::types::RetryConfig;
15
use crate::core::{ConnectionMode, Worker, WorkerRegistry, WorkerType};
16
use crate::grpc_client::{proto, SglangSchedulerClient};
17
use crate::metrics::RouterMetrics;
18
use crate::policies::PolicyRegistry;
19
use crate::protocols::spec::ChatMessage;
20
use crate::protocols::spec::{ChatCompletionRequest, StringOrArray};
21
22
23
24
use crate::protocols::spec::{
    CompletionRequest, EmbeddingRequest, GenerateRequest, RerankRequest, ResponsesGetParams,
    ResponsesRequest, Tool, ToolChoice,
};
25
use crate::reasoning_parser::ParserFactory;
26
use crate::routers::RouterTrait;
27
28
use crate::server::AppContext;
use crate::tokenizer::chat_template::{ChatTemplateContentFormat, ChatTemplateParams};
29
use crate::tokenizer::traits::Tokenizer;
30
use crate::tokenizer::HuggingFaceTokenizer;
31
use crate::tool_parser::ParserRegistry;
32
use serde_json::Value;
33
use uuid::Uuid;
34

35
36
37
38
39
40
41
// Data structures for processing
#[derive(Debug)]
pub struct ProcessedMessages {
    pub text: String,
    pub multimodal_inputs: Option<proto::MultimodalInputs>,
    pub stop_sequences: Option<StringOrArray>,
}
42

43
/// gRPC router implementation for SGLang
44
#[allow(dead_code)]
45
pub struct GrpcRouter {
46
47
    worker_registry: Arc<WorkerRegistry>,
    policy_registry: Arc<PolicyRegistry>,
48
49
50
51
52
53
54
    tokenizer: Arc<dyn Tokenizer>,
    reasoning_parser_factory: ParserFactory,
    tool_parser_registry: &'static ParserRegistry,
    dp_aware: bool,
    api_key: Option<String>,
    retry_config: RetryConfig,
}
55
56

impl GrpcRouter {
57
    /// Create a new gRPC router
58
    pub async fn new(ctx: &Arc<AppContext>) -> Result<Self, String> {
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
        // Extract necessary components from context
        let tokenizer = ctx
            .tokenizer
            .as_ref()
            .ok_or_else(|| "gRPC router requires tokenizer".to_string())?
            .clone();
        let reasoning_parser_factory = ctx
            .reasoning_parser_factory
            .as_ref()
            .ok_or_else(|| "gRPC router requires reasoning parser factory".to_string())?
            .clone();
        let tool_parser_registry = ctx
            .tool_parser_registry
            .ok_or_else(|| "gRPC router requires tool parser registry".to_string())?;

74
75
        let worker_registry = ctx.worker_registry.clone();
        let policy_registry = ctx.policy_registry.clone();
Chang Su's avatar
Chang Su committed
76

77
        let workers = worker_registry.get_workers_filtered(
78
            None,
79
            Some(WorkerType::Regular),
80
            Some(ConnectionMode::Grpc { port: None }),
81
            false,
82
83
        );

84
85
        RouterMetrics::set_active_workers(workers.len());
        info!("gRPC router found {} workers in registry", workers.len());
86
87

        Ok(GrpcRouter {
88
89
            worker_registry,
            policy_registry,
90
91
92
            tokenizer,
            reasoning_parser_factory,
            tool_parser_registry,
93
94
95
            dp_aware: ctx.router_config.dp_aware,
            api_key: ctx.router_config.api_key.clone(),
            retry_config: ctx.router_config.effective_retry_config(),
96
97
        })
    }
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121

    /// Main route_chat implementation
    async fn route_chat_impl(
        &self,
        _headers: Option<&HeaderMap>,
        body: &ChatCompletionRequest,
        model_id: Option<&str>,
    ) -> Response {
        debug!(
            "Processing chat completion request for model: {:?}",
            model_id
        );

        // Step 1: Select worker (fail fast if no workers available)
        let worker = match self.select_worker_for_request(model_id, None) {
            Some(w) => w,
            None => {
                warn!("No available workers for model: {:?}", model_id);
                return (StatusCode::SERVICE_UNAVAILABLE, "No available workers").into_response();
            }
        };

        debug!("Selected worker: {}", worker.url());

122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
        // Step 2: Get gRPC client from worker
        let client = match worker.get_grpc_client().await {
            Ok(Some(client_arc)) => {
                // Clone the client from inside the Arc<Mutex<>>
                let client = client_arc.lock().await.clone();
                client
            }
            Ok(None) => {
                error!("Selected worker is not a gRPC worker");
                return (
                    StatusCode::INTERNAL_SERVER_ERROR,
                    "Selected worker is not configured for gRPC",
                )
                    .into_response();
            }
137
            Err(e) => {
138
                error!("Failed to get gRPC client from worker: {}", e);
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
                return (
                    StatusCode::INTERNAL_SERVER_ERROR,
                    format!("Failed to get gRPC client: {}", e),
                )
                    .into_response();
            }
        };

        // Step 3: Process messages and apply chat template
        let processed_messages = match self.process_chat_messages(body) {
            Ok(msgs) => msgs,
            Err(e) => {
                error!("Failed to process chat messages: {}", e);
                return (StatusCode::BAD_REQUEST, e.to_string()).into_response();
            }
        };

        // Step 4: Tokenize the processed text
        let encoding = match self.tokenizer.encode(&processed_messages.text) {
            Ok(encoding) => encoding,
            Err(e) => {
                error!("Tokenization failed: {}", e);
                return (
                    StatusCode::INTERNAL_SERVER_ERROR,
                    format!("Tokenization failed: {}", e),
                )
                    .into_response();
            }
        };

        let token_ids = encoding.token_ids().to_vec();
        debug!("Tokenized {} tokens from input", token_ids.len());

        // Step 5: Build tool constraints if needed
173
        let tool_call_constraint = if let Some(tools) = &body.tools {
174
175
176
177
178
            self.generate_tool_constraints(tools, &body.tool_choice, &body.model)
        } else {
            None
        };

179
180
        // Step 6: Build the base gRPC request
        let request_id = format!("chatcmpl-{}", Uuid::new_v4());
181
        let request = match client.build_generate_request(
182
183
184
185
186
187
188
189
            request_id,
            body,
            processed_messages.text.clone(),
            token_ids.into_iter().map(|id| id as i32).collect(),
            processed_messages.multimodal_inputs,
            tool_call_constraint, // Pass the full tuple (type, value)
        ) {
            Ok(request) => request,
190
            Err(e) => {
191
                error!("Failed to build gRPC request: {}", e);
192
193
                return (
                    StatusCode::BAD_REQUEST,
194
                    format!("Invalid request parameters: {}", e),
195
196
197
198
199
                )
                    .into_response();
            }
        };

200
        // Step 7: Handle streaming vs non-streaming
201
        if body.stream {
202
            self.handle_streaming_chat(client, request, body).await
203
        } else {
204
            self.handle_non_streaming_chat(client, request, body).await
205
206
207
        }
    }

208
209
210
211
212
    /// Select a worker for the request
    fn select_worker_for_request(
        &self,
        model_id: Option<&str>,
        text: Option<&str>,
213
    ) -> Option<Arc<dyn Worker>> {
214
215
216
217
        // Get workers for the specified model, filtered by connection mode
        let workers = self.worker_registry.get_workers_filtered(
            model_id,
            Some(WorkerType::Regular),
218
            Some(ConnectionMode::Grpc { port: None }),
219
220
221
222
            false, // get all workers, we'll filter by is_available() next
        );

        // Filter by availability (health + circuit breaker)
223
        let available: Vec<Arc<dyn Worker>> = workers
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
            .iter()
            .filter(|w| w.is_available())
            .cloned()
            .collect();

        if available.is_empty() {
            return None;
        }

        // Get the appropriate policy for this model
        let policy = match model_id {
            Some(model) => self.policy_registry.get_policy_or_default(model),
            None => self.policy_registry.get_default_policy(),
        };

        // Select worker using the policy
        let idx = policy.select_worker(&available, text)?;
        Some(available[idx].clone())
    }
243
244
245
246
247
248
249

    /// Process chat messages and apply template
    fn process_chat_messages(
        &self,
        request: &ChatCompletionRequest,
    ) -> Result<ProcessedMessages, String> {
        // Use the tokenizer's chat template - we require HuggingFace tokenizer for gRPC
250
251
252
253
        let formatted_text = if let Some(hf_tokenizer) = self
            .tokenizer
            .as_any()
            .downcast_ref::<HuggingFaceTokenizer>()
254
        {
255
256
            // Get content format and transform messages accordingly
            let content_format = hf_tokenizer.chat_template_content_format();
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
            let mut transformed_messages =
                Self::process_content_format(&request.messages, content_format)?;

            // Process tool call arguments in assistant messages
            Self::process_tool_call_arguments(&mut transformed_messages)?;

            // Convert tools to JSON values for template processing
            let tools_json: Option<Vec<serde_json::Value>> = request
                .tools
                .as_ref()
                .map(|tools| {
                    tools
                        .iter()
                        .map(serde_json::to_value)
                        .collect::<Result<Vec<_>, _>>()
                })
                .transpose()
                .map_err(|e| format!("Failed to serialize tools: {}", e))?;

            // Build template kwargs, merging reasoning_effort if present
            let mut combined_template_kwargs = std::collections::HashMap::new();

            // Add reasoning_effort if present (like Python does)
            if let Some(reasoning_effort) = &request.reasoning_effort {
                combined_template_kwargs.insert(
                    "reasoning_effort".to_string(),
                    serde_json::Value::String(reasoning_effort.clone()),
                );
            }

            // Add any additional template kwargs from request
            if let Some(template_kwargs) = &request.chat_template_kwargs {
                for (key, value) in template_kwargs {
                    combined_template_kwargs.insert(key.clone(), value.clone());
                }
            }

            let final_template_kwargs = if combined_template_kwargs.is_empty() {
                None
            } else {
                Some(&combined_template_kwargs)
            };

            let params = ChatTemplateParams {
                add_generation_prompt: true,
                continue_final_message: request.continue_final_message,
                tools: tools_json.as_deref(),
                template_kwargs: final_template_kwargs,
                ..Default::default()
            };

            // Handle assistant prefix for continue_final_message
            let assistant_prefix = if request.continue_final_message
                && !transformed_messages.is_empty()
                && transformed_messages
                    .last()
                    .and_then(|msg| msg.get("role"))
                    .and_then(|v| v.as_str())
                    == Some("assistant")
            {
                // Pop the last message to handle it separately
                let last_msg = transformed_messages.pop().unwrap();
                last_msg
                    .get("content")
                    .and_then(|v| v.as_str())
                    .map(|s| s.to_string())
            } else {
                None
            };

            // Apply chat template with the (now possibly shorter) list of messages
            let rendered = hf_tokenizer
                .apply_chat_template(&transformed_messages, params)
                .map_err(|e| format!("Failed to apply chat template: {}", e))?;
331

332
333
334
335
336
337
            // Append assistant prefix if we have one
            if let Some(prefix) = assistant_prefix {
                format!("{}{}", rendered, prefix)
            } else {
                rendered
            }
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
        } else {
            return Err(
                "gRPC router requires HuggingFace tokenizer with chat template support".to_string(),
            );
        };

        // Placeholder for multimodal inputs
        let multimodal_inputs = None;

        Ok(ProcessedMessages {
            text: formatted_text,
            multimodal_inputs,
            stop_sequences: request.stop.clone(),
        })
    }

354
355
    /// Process messages based on content format for ANY message type
    fn process_content_format(
356
357
358
        messages: &[ChatMessage],
        content_format: ChatTemplateContentFormat,
    ) -> Result<Vec<Value>, String> {
359
360
361
362
363
364
365
366
367
368
        messages
            .iter()
            .map(|message| {
                let mut message_json = serde_json::to_value(message)
                    .map_err(|e| format!("Failed to serialize message: {}", e))?;

                if let Some(obj) = message_json.as_object_mut() {
                    if let Some(content_value) = obj.get_mut("content") {
                        Self::transform_content_field(content_value, content_format);
                    }
369
                }
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401

                Ok(message_json)
            })
            .collect()
    }

    /// Transform a single content field based on content format
    fn transform_content_field(
        content_value: &mut Value,
        content_format: ChatTemplateContentFormat,
    ) {
        let Some(content_array) = content_value.as_array() else {
            return; // Not multimodal, keep as-is
        };

        match content_format {
            ChatTemplateContentFormat::String => {
                // Extract and join text parts only
                let text_parts: Vec<String> = content_array
                    .iter()
                    .filter_map(|part| {
                        part.as_object()?
                            .get("type")?
                            .as_str()
                            .filter(|&t| t == "text")
                            .and_then(|_| part.as_object()?.get("text")?.as_str())
                            .map(String::from)
                    })
                    .collect();

                if !text_parts.is_empty() {
                    *content_value = Value::String(text_parts.join(" "));
402
                }
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
            }
            ChatTemplateContentFormat::OpenAI => {
                // Replace media URLs with simple type placeholders
                let processed_parts: Vec<Value> = content_array
                    .iter()
                    .map(|part| {
                        part.as_object()
                            .and_then(|obj| obj.get("type")?.as_str())
                            .and_then(|type_str| match type_str {
                                "image_url" => Some(serde_json::json!({"type": "image"})),
                                "video_url" => Some(serde_json::json!({"type": "video"})),
                                "audio_url" => Some(serde_json::json!({"type": "audio"})),
                                _ => None,
                            })
                            .unwrap_or_else(|| part.clone())
                    })
                    .collect();
420

421
422
423
                *content_value = Value::Array(processed_parts);
            }
        }
424
425
    }

426
427
    /// Process tool call arguments in messages
    /// Per Transformers docs, tool call arguments in assistant messages should be dicts
428
    fn process_tool_call_arguments(messages: &mut [Value]) -> Result<(), String> {
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
        for msg in messages {
            // Early return if not assistant message
            let role = msg.get("role").and_then(|v| v.as_str());
            if role != Some("assistant") {
                continue;
            }

            // Early return if no tool_calls
            let Some(tool_calls) = msg.get_mut("tool_calls").and_then(|tc| tc.as_array_mut())
            else {
                continue;
            };

            // Process each tool call's arguments
            for call in tool_calls {
                let Some(function) = call.get_mut("function") else {
                    continue;
                };
                let Some(args) = function.get_mut("arguments") else {
                    continue;
                };
                let Some(args_str) = args.as_str() else {
                    continue;
                };

                // Parse JSON string to object (like Python json.loads)
                match serde_json::from_str::<serde_json::Value>(args_str) {
                    Ok(parsed) => *args = parsed,
                    Err(e) => {
                        return Err(format!(
                            "Failed to parse tool call arguments as JSON: '{}'. Error: {}",
                            args_str, e
                        ))
                    }
                }
            }
        }
        Ok(())
    }

469
470
471
    /// Generate tool constraints for structured generation
    fn generate_tool_constraints(
        &self,
472
473
        _tools: &[Tool],
        _tool_choice: &Option<ToolChoice>,
474
        model: &str,
475
    ) -> Option<(String, String)> {
476
        let _parser = self.tool_parser_registry.get_parser(model)?;
477
478
        // TODO: Implement actual constraint generation logic
        // For now, return None as this is placeholder implementation
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
        None
    }

    /// Placeholder for streaming handler (to be implemented in Phase 2)
    async fn handle_streaming_chat(
        &self,
        _client: SglangSchedulerClient,
        _request: proto::GenerateRequest,
        _original_request: &ChatCompletionRequest,
    ) -> Response {
        (StatusCode::NOT_IMPLEMENTED, "Streaming not yet implemented").into_response()
    }

    /// Placeholder for non-streaming handler (to be implemented in Phase 3)
    async fn handle_non_streaming_chat(
        &self,
        _client: SglangSchedulerClient,
        _request: proto::GenerateRequest,
        _original_request: &ChatCompletionRequest,
    ) -> Response {
        (
            StatusCode::NOT_IMPLEMENTED,
            "Non-streaming not yet implemented",
        )
            .into_response()
    }
505
506
507
508
}

impl std::fmt::Debug for GrpcRouter {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
509
        let stats = self.worker_registry.stats();
510
        f.debug_struct("GrpcRouter")
511
            .field("workers_count", &stats.total_workers)
512
513
            .field("dp_aware", &self.dp_aware)
            .finish()
514
515
516
517
518
519
520
521
522
523
    }
}

#[async_trait]
impl RouterTrait for GrpcRouter {
    fn as_any(&self) -> &dyn std::any::Any {
        self
    }

    async fn health_generate(&self, _req: Request<Body>) -> Response {
524
525
526
527
528
529
        // TODO: Implement actual generation test for gRPC
        (
            StatusCode::NOT_IMPLEMENTED,
            "Health generate not yet implemented for gRPC",
        )
            .into_response()
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
    }

    async fn get_server_info(&self, _req: Request<Body>) -> Response {
        (StatusCode::NOT_IMPLEMENTED).into_response()
    }

    async fn get_models(&self, _req: Request<Body>) -> Response {
        (StatusCode::NOT_IMPLEMENTED).into_response()
    }

    async fn get_model_info(&self, _req: Request<Body>) -> Response {
        (StatusCode::NOT_IMPLEMENTED).into_response()
    }

    async fn route_generate(
        &self,
        _headers: Option<&HeaderMap>,
547
        _body: &GenerateRequest,
548
        _model_id: Option<&str>,
549
550
551
552
553
554
    ) -> Response {
        (StatusCode::NOT_IMPLEMENTED).into_response()
    }

    async fn route_chat(
        &self,
555
        headers: Option<&HeaderMap>,
556
        body: &ChatCompletionRequest,
557
        model_id: Option<&str>,
558
    ) -> Response {
559
        self.route_chat_impl(headers, body, model_id).await
560
561
562
563
564
    }

    async fn route_completion(
        &self,
        _headers: Option<&HeaderMap>,
565
        _body: &CompletionRequest,
566
        _model_id: Option<&str>,
567
568
569
570
    ) -> Response {
        (StatusCode::NOT_IMPLEMENTED).into_response()
    }

571
572
573
    async fn route_responses(
        &self,
        _headers: Option<&HeaderMap>,
574
        _body: &ResponsesRequest,
575
        _model_id: Option<&str>,
576
577
578
579
    ) -> Response {
        (StatusCode::NOT_IMPLEMENTED).into_response()
    }

580
581
582
583
    async fn get_response(
        &self,
        _headers: Option<&HeaderMap>,
        _response_id: &str,
584
        _params: &ResponsesGetParams,
585
    ) -> Response {
586
587
588
589
590
591
592
        (StatusCode::NOT_IMPLEMENTED).into_response()
    }

    async fn cancel_response(&self, _headers: Option<&HeaderMap>, _response_id: &str) -> Response {
        (StatusCode::NOT_IMPLEMENTED).into_response()
    }

593
594
595
    async fn route_embeddings(
        &self,
        _headers: Option<&HeaderMap>,
596
        _body: &EmbeddingRequest,
597
598
        _model_id: Option<&str>,
    ) -> Response {
599
600
601
        (StatusCode::NOT_IMPLEMENTED).into_response()
    }

602
603
604
    async fn route_rerank(
        &self,
        _headers: Option<&HeaderMap>,
605
        _body: &RerankRequest,
606
        _model_id: Option<&str>,
607
    ) -> Response {
608
609
610
611
612
613
614
        (StatusCode::NOT_IMPLEMENTED).into_response()
    }

    fn router_type(&self) -> &'static str {
        "grpc"
    }
}
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643

#[cfg(test)]
mod tests {
    use super::*;
    use crate::protocols::spec::{ChatMessage, ContentPart, ImageUrl, UserMessageContent};
    use crate::tokenizer::chat_template::ChatTemplateContentFormat;
    use serde_json::json;

    #[test]
    fn test_transform_messages_string_format() {
        let messages = vec![ChatMessage::User {
            role: "user".to_string(),
            content: UserMessageContent::Parts(vec![
                ContentPart::Text {
                    text: "Hello".to_string(),
                },
                ContentPart::ImageUrl {
                    image_url: ImageUrl {
                        url: "https://example.com/image.jpg".to_string(),
                        detail: None,
                    },
                },
                ContentPart::Text {
                    text: "World".to_string(),
                },
            ]),
            name: None,
        }];

644
645
646
        let result =
            GrpcRouter::process_content_format(&messages, ChatTemplateContentFormat::String)
                .unwrap();
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676

        assert_eq!(result.len(), 1);
        let transformed_message = &result[0];

        // Should flatten multimodal content to text only
        assert_eq!(
            transformed_message["content"].as_str().unwrap(),
            "Hello World"
        );
        assert_eq!(transformed_message["role"].as_str().unwrap(), "user");
    }

    #[test]
    fn test_transform_messages_openai_format() {
        let messages = vec![ChatMessage::User {
            role: "user".to_string(),
            content: UserMessageContent::Parts(vec![
                ContentPart::Text {
                    text: "Describe this image:".to_string(),
                },
                ContentPart::ImageUrl {
                    image_url: ImageUrl {
                        url: "https://example.com/image.jpg".to_string(),
                        detail: Some("high".to_string()),
                    },
                },
            ]),
            name: None,
        }];

677
678
679
        let result =
            GrpcRouter::process_content_format(&messages, ChatTemplateContentFormat::OpenAI)
                .unwrap();
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703

        assert_eq!(result.len(), 1);
        let transformed_message = &result[0];

        // Should replace media URLs with simple type placeholders
        let content_array = transformed_message["content"].as_array().unwrap();
        assert_eq!(content_array.len(), 2);

        // Text part should remain unchanged
        assert_eq!(content_array[0]["type"], "text");
        assert_eq!(content_array[0]["text"], "Describe this image:");

        // Image part should be replaced with simple type placeholder
        assert_eq!(content_array[1], json!({"type": "image"}));
    }

    #[test]
    fn test_transform_messages_simple_string_content() {
        let messages = vec![ChatMessage::User {
            role: "user".to_string(),
            content: UserMessageContent::Text("Simple text message".to_string()),
            name: None,
        }];

704
705
706
        let result =
            GrpcRouter::process_content_format(&messages, ChatTemplateContentFormat::String)
                .unwrap();
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728

        assert_eq!(result.len(), 1);
        let transformed_message = &result[0];

        // Simple string content should remain unchanged
        assert_eq!(
            transformed_message["content"].as_str().unwrap(),
            "Simple text message"
        );
    }

    #[test]
    fn test_transform_messages_assistant_message() {
        let messages = vec![ChatMessage::Assistant {
            role: "assistant".to_string(),
            content: Some("Assistant response".to_string()),
            name: None,
            tool_calls: None,
            function_call: None,
            reasoning_content: None,
        }];

729
730
731
        let result =
            GrpcRouter::process_content_format(&messages, ChatTemplateContentFormat::String)
                .unwrap();
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767

        assert_eq!(result.len(), 1);
        let transformed_message = &result[0];

        assert_eq!(transformed_message["role"].as_str().unwrap(), "assistant");
        assert_eq!(
            transformed_message["content"].as_str().unwrap(),
            "Assistant response"
        );
    }

    #[test]
    fn test_transform_messages_multiple_messages() {
        let messages = vec![
            ChatMessage::System {
                role: "system".to_string(),
                content: "System prompt".to_string(),
                name: None,
            },
            ChatMessage::User {
                role: "user".to_string(),
                content: UserMessageContent::Parts(vec![
                    ContentPart::Text {
                        text: "User message".to_string(),
                    },
                    ContentPart::ImageUrl {
                        image_url: ImageUrl {
                            url: "https://example.com/image.jpg".to_string(),
                            detail: None,
                        },
                    },
                ]),
                name: None,
            },
        ];

768
769
770
        let result =
            GrpcRouter::process_content_format(&messages, ChatTemplateContentFormat::String)
                .unwrap();
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795

        assert_eq!(result.len(), 2);

        // System message should remain unchanged
        assert_eq!(result[0]["role"].as_str().unwrap(), "system");
        assert_eq!(result[0]["content"].as_str().unwrap(), "System prompt");

        // User message should be flattened to text only
        assert_eq!(result[1]["role"].as_str().unwrap(), "user");
        assert_eq!(result[1]["content"].as_str().unwrap(), "User message");
    }

    #[test]
    fn test_transform_messages_empty_text_parts() {
        let messages = vec![ChatMessage::User {
            role: "user".to_string(),
            content: UserMessageContent::Parts(vec![ContentPart::ImageUrl {
                image_url: ImageUrl {
                    url: "https://example.com/image.jpg".to_string(),
                    detail: None,
                },
            }]),
            name: None,
        }];

796
797
798
        let result =
            GrpcRouter::process_content_format(&messages, ChatTemplateContentFormat::String)
                .unwrap();
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831

        assert_eq!(result.len(), 1);
        let transformed_message = &result[0];

        // Should keep original multimodal content when no text parts exist
        assert!(transformed_message["content"].is_array());
    }

    #[test]
    fn test_transform_messages_mixed_content_types() {
        let messages = vec![
            ChatMessage::User {
                role: "user".to_string(),
                content: UserMessageContent::Text("Plain text".to_string()),
                name: None,
            },
            ChatMessage::User {
                role: "user".to_string(),
                content: UserMessageContent::Parts(vec![
                    ContentPart::Text {
                        text: "With image".to_string(),
                    },
                    ContentPart::ImageUrl {
                        image_url: ImageUrl {
                            url: "https://example.com/image.jpg".to_string(),
                            detail: Some("low".to_string()),
                        },
                    },
                ]),
                name: None,
            },
        ];

832
833
834
        let result_string =
            GrpcRouter::process_content_format(&messages, ChatTemplateContentFormat::String)
                .unwrap();
835
836
837
838
839

        assert_eq!(result_string.len(), 2);
        assert_eq!(result_string[0]["content"].as_str().unwrap(), "Plain text");
        assert_eq!(result_string[1]["content"].as_str().unwrap(), "With image");

840
841
842
        let result_openai =
            GrpcRouter::process_content_format(&messages, ChatTemplateContentFormat::OpenAI)
                .unwrap();
843
844
845
846
847
848
849
850
851
852

        assert_eq!(result_openai.len(), 2);
        assert_eq!(result_openai[0]["content"].as_str().unwrap(), "Plain text");

        let content_array = result_openai[1]["content"].as_array().unwrap();
        assert_eq!(content_array.len(), 2);
        assert_eq!(content_array[0]["type"], "text");
        assert_eq!(content_array[1], json!({"type": "image"}));
    }
}