OpenAI function calling compatible support (#1888)

# What does this PR do?

<!-- Remove if not applicable -->

Fixes # (issue)
https://github.com/huggingface/text-generation-inference/issues/1887

## Before submitting
- [no ] This PR fixes a typo or improves the docs (you can dismiss the
other checks if that's the case).
- [yes] Did you read the [contributor
guideline](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md#start-contributing-pull-requests),
      Pull Request section?
- [ yes] Was this discussed/approved via a Github issue or the
[forum](https://discuss.huggingface.co/)? Please add a link
      to it if that's the case.
- [yes ] Did you make sure to update the documentation with your
changes? Here are the
[documentation
guidelines](https://github.com/huggingface/transformers/tree/main/docs),
and
[here are tips on formatting
docstrings](https://github.com/huggingface/transformers/tree/main/docs#writing-source-documentation).
- [ yes] Did you write any new necessary tests?


## Who can review?

Anyone in the community is free to review the PR once the tests have
passed. Feel free to tag
members/contributors who may be interested in your PR.

@Narsil

 -->

---------

Co-authored-by: Bao Phan <baopg@inter-k.com>

router/src/infer.rs

@@ -979,24 +979,28 @@ mod tests {
                     content: Some("Hi!".to_string()),
                     name: None,
                     tool_calls: None,
+                    tool_call_id: None,
                 },
                 Message {
                     role: "assistant".to_string(),
                     content: Some("Hello how can I help?".to_string()),
                     name: None,
                     tool_calls: None,
+                    tool_call_id: None,
                 },
                 Message {
                     role: "user".to_string(),
                     content: Some("What is Deep Learning?".to_string()),
                     name: None,
                     tool_calls: None,
+                    tool_call_id: None,
                 },
                 Message {
                     role: "assistant".to_string(),
                     content: Some("magic!".to_string()),
                     name: None,
                     tool_calls: None,
+                    tool_call_id: None,
                 },
             ],
             bos_token: Some("[BOS]"),
@@ -1049,30 +1053,35 @@ mod tests {
                     content: Some("Hi!".to_string()),
                     name: None,
                     tool_calls: None,
+                    tool_call_id: None,
                 },
                 Message {
                     role: "user".to_string(),
                     content: Some("Hi again!".to_string()),
                     name: None,
                     tool_calls: None,
+                    tool_call_id: None,
                 },
                 Message {
                     role: "assistant".to_string(),
                     content: Some("Hello how can I help?".to_string()),
                     name: None,
                     tool_calls: None,
+                    tool_call_id: None,
                 },
                 Message {
                     role: "user".to_string(),
                     content: Some("What is Deep Learning?".to_string()),
                     name: None,
                     tool_calls: None,
+                    tool_call_id: None,
                 },
                 Message {
                     role: "assistant".to_string(),
                     content: Some("magic!".to_string()),
                     name: None,
                     tool_calls: None,
+                    tool_call_id: None,
                 },
             ],
             bos_token: Some("[BOS]"),
@@ -1130,24 +1139,28 @@ mod tests {
                     content: Some("Hi!".to_string()),
                     name: None,
                     tool_calls: None,
+                    tool_call_id: None,
                 },
                 Message {
                     role: "assistant".to_string(),
                     content: Some("Hello how can I help?".to_string()),
                     name: None,
                     tool_calls: None,
+                    tool_call_id: None,
                 },
                 Message {
                     role: "user".to_string(),
                     content: Some("What is Deep Learning?".to_string()),
                     name: None,
                     tool_calls: None,
+                    tool_call_id: None,
                 },
                 Message {
                     role: "assistant".to_string(),
                     content: Some("magic!".to_string()),
                     name: None,
                     tool_calls: None,
+                    tool_call_id: None,
                 },
             ],
             bos_token: Some("[BOS]"),
@@ -1189,24 +1202,28 @@ mod tests {
                     content: Some("Hi!".to_string()),
                     name: None,
                     tool_calls: None,
+                    tool_call_id: None,
                 },
                 Message {
                     role: "assistant".to_string(),
                     content: Some("Hello how can I help?".to_string()),
                     name: None,
                     tool_calls: None,
+                    tool_call_id: None,
                 },
                 Message {
                     role: "user".to_string(),
                     content: Some("What is Deep Learning?".to_string()),
                     name: None,
                     tool_calls: None,
+                    tool_call_id: None,
                 },
                 Message {
                     role: "assistant".to_string(),
                     content: Some("magic!".to_string()),
                     name: None,
                     tool_calls: None,
+                    tool_call_id: None,
                 },
             ],
             bos_token: Some("[BOS]"),
@@ -1234,18 +1251,21 @@ mod tests {
                 content: Some("Hello, how are you?".to_string()),
                 name: None,
                 tool_calls: None,
+                tool_call_id: None,
             },
             Message {
                 role: "assistant".to_string(),
                 content: Some("I'm doing great. How can I help you today?".to_string()),
                 name: None,
                 tool_calls: None,
+                tool_call_id: None,
             },
             Message {
                 role: "user".to_string(),
                 content: Some("I'd like to show off how chat templating works!".to_string()),
                 name: None,
                 tool_calls: None,
+                tool_call_id: None,
             },
         ];
 
@@ -1257,6 +1277,7 @@ mod tests {
             ),
             name: None,
             tool_calls: None,
+            tool_call_id: None,
         }]
         .iter()
         .chain(&example_chat)
@@ -1401,12 +1422,14 @@ mod tests {
                             content: Some("You are a friendly chatbot who always responds in the style of a pirate".to_string()),
                             name: None,
                             tool_calls: None,
+                            tool_call_id: None,
                         },
                         Message {
                             role: "user".to_string(),
                             content: Some("How many helicopters can a human eat in one sitting?".to_string()),
                             name: None,
                             tool_calls: None,
+                            tool_call_id: None,
                         },
                     ],
                     add_generation_prompt: true,

router/src/lib.rs

@@ -546,6 +546,7 @@ impl ChatCompletion {
                     content: output,
                     name: None,
                     tool_calls,
+                    tool_call_id: None,
                 },
                 logprobs: return_logprobs
                     .then(|| ChatCompletionLogprobs::from((details.tokens, details.top_tokens))),
@@ -881,7 +882,7 @@ pub(crate) struct ChatTemplateInputs<'a> {
 
 #[derive(Clone, Deserialize, Serialize, ToSchema, Default, Debug)]
 pub(crate) struct ToolCall {
-    pub id: u32,
+    pub id: String,
     pub r#type: String,
     pub function: FunctionDefinition,
 }
@@ -954,13 +955,16 @@ pub(crate) struct Message {
     pub role: String,
     #[serde(skip_serializing_if = "Option::is_none")]
     #[schema(example = "My name is David and I")]
-    #[serde(deserialize_with = "message_content_serde::deserialize")]
+    #[serde(default, deserialize_with = "message_content_serde::deserialize")]
     pub content: Option<String>,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     #[schema(example = "\"David\"")]
     pub name: Option<String>,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     pub tool_calls: Option<Vec<ToolCall>>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    #[schema(example = "\"get_weather\"")]
+    pub tool_call_id: Option<String>,
 }
 
 #[derive(Clone, Debug, Deserialize, ToSchema)]

router/src/server.rs

@@ -988,7 +988,6 @@ async fn chat_completions(
 ) -> Result<Response, (StatusCode, Json<ErrorResponse>)> {
     let span = tracing::Span::current();
     metrics::increment_counter!("tgi_request_count");
-
     let ChatRequest {
         logprobs,
         max_tokens,
@@ -1160,7 +1159,7 @@ async fn chat_completions(
                     )
                 })?;
             let tool_calls = vec![ToolCall {
-                id: 0,
+                id: "0".to_string(),
                 r#type: "function".to_string(),
                 function: FunctionDefinition {
                     description: None,