ZIm/crates/lmstudio/src/lmstudio.rs
Richard Feldman 5405c2c2d3
Standardize on u64 for token counts (#32869)
Previously we were using a mix of `u32` and `usize`, e.g. `max_tokens:
usize, max_output_tokens: Option<u32>` in the same `struct`.

Although [tiktoken](https://github.com/openai/tiktoken) uses `usize`,
token counts should be consistent across targets (e.g. the same model
doesn't suddenly get a smaller context window if you're compiling for
wasm32), and these token counts could end up getting serialized using a
binary protocol, so `usize` is not the right choice for token counts.

I chose to standardize on `u64` over `u32` because we don't store many
of them (so the extra size should be insignificant) and future models
may exceed `u32::MAX` tokens.

Release Notes:

- N/A
2025-06-17 10:43:07 -04:00

493 lines
14 KiB
Rust

use anyhow::{Context as _, Result};
use futures::{AsyncBufReadExt, AsyncReadExt, StreamExt, io::BufReader, stream::BoxStream};
use http_client::{AsyncBody, HttpClient, Method, Request as HttpRequest, http};
use serde::{Deserialize, Serialize};
use serde_json::Value;
use std::{convert::TryFrom, time::Duration};
pub const LMSTUDIO_API_URL: &str = "http://localhost:1234/api/v0";
#[derive(Clone, Copy, Serialize, Deserialize, Debug, Eq, PartialEq)]
#[serde(rename_all = "lowercase")]
pub enum Role {
User,
Assistant,
System,
Tool,
}
impl TryFrom<String> for Role {
type Error = anyhow::Error;
fn try_from(value: String) -> Result<Self> {
match value.as_str() {
"user" => Ok(Self::User),
"assistant" => Ok(Self::Assistant),
"system" => Ok(Self::System),
"tool" => Ok(Self::Tool),
_ => anyhow::bail!("invalid role '{value}'"),
}
}
}
impl From<Role> for String {
fn from(val: Role) -> Self {
match val {
Role::User => "user".to_owned(),
Role::Assistant => "assistant".to_owned(),
Role::System => "system".to_owned(),
Role::Tool => "tool".to_owned(),
}
}
}
#[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
#[derive(Clone, Debug, Default, Serialize, Deserialize, PartialEq)]
pub struct Model {
pub name: String,
pub display_name: Option<String>,
pub max_tokens: u64,
pub supports_tool_calls: bool,
pub supports_images: bool,
}
impl Model {
pub fn new(
name: &str,
display_name: Option<&str>,
max_tokens: Option<u64>,
supports_tool_calls: bool,
supports_images: bool,
) -> Self {
Self {
name: name.to_owned(),
display_name: display_name.map(|s| s.to_owned()),
max_tokens: max_tokens.unwrap_or(2048),
supports_tool_calls,
supports_images,
}
}
pub fn id(&self) -> &str {
&self.name
}
pub fn display_name(&self) -> &str {
self.display_name.as_ref().unwrap_or(&self.name)
}
pub fn max_token_count(&self) -> u64 {
self.max_tokens
}
pub fn supports_tool_calls(&self) -> bool {
self.supports_tool_calls
}
}
#[derive(Debug, Serialize, Deserialize)]
#[serde(untagged)]
pub enum ToolChoice {
Auto,
Required,
None,
Other(ToolDefinition),
}
#[derive(Clone, Deserialize, Serialize, Debug)]
#[serde(tag = "type", rename_all = "snake_case")]
pub enum ToolDefinition {
#[allow(dead_code)]
Function { function: FunctionDefinition },
}
#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct FunctionDefinition {
pub name: String,
pub description: Option<String>,
pub parameters: Option<Value>,
}
#[derive(Serialize, Deserialize, Debug)]
#[serde(tag = "role", rename_all = "lowercase")]
pub enum ChatMessage {
Assistant {
#[serde(default)]
content: Option<MessageContent>,
#[serde(default, skip_serializing_if = "Vec::is_empty")]
tool_calls: Vec<ToolCall>,
},
User {
content: MessageContent,
},
System {
content: MessageContent,
},
Tool {
content: MessageContent,
tool_call_id: String,
},
}
#[derive(Serialize, Deserialize, Debug, Eq, PartialEq)]
#[serde(untagged)]
pub enum MessageContent {
Plain(String),
Multipart(Vec<MessagePart>),
}
impl MessageContent {
pub fn empty() -> Self {
MessageContent::Multipart(vec![])
}
pub fn push_part(&mut self, part: MessagePart) {
match self {
MessageContent::Plain(text) => {
*self =
MessageContent::Multipart(vec![MessagePart::Text { text: text.clone() }, part]);
}
MessageContent::Multipart(parts) if parts.is_empty() => match part {
MessagePart::Text { text } => *self = MessageContent::Plain(text),
MessagePart::Image { .. } => *self = MessageContent::Multipart(vec![part]),
},
MessageContent::Multipart(parts) => parts.push(part),
}
}
}
impl From<Vec<MessagePart>> for MessageContent {
fn from(mut parts: Vec<MessagePart>) -> Self {
if let [MessagePart::Text { text }] = parts.as_mut_slice() {
MessageContent::Plain(std::mem::take(text))
} else {
MessageContent::Multipart(parts)
}
}
}
#[derive(Serialize, Deserialize, Debug, Eq, PartialEq)]
#[serde(tag = "type", rename_all = "snake_case")]
pub enum MessagePart {
Text {
text: String,
},
#[serde(rename = "image_url")]
Image {
image_url: ImageUrl,
},
}
#[derive(Serialize, Deserialize, Clone, Debug, Eq, PartialEq)]
pub struct ImageUrl {
pub url: String,
#[serde(skip_serializing_if = "Option::is_none")]
pub detail: Option<String>,
}
#[derive(Serialize, Deserialize, Debug, Eq, PartialEq)]
pub struct ToolCall {
pub id: String,
#[serde(flatten)]
pub content: ToolCallContent,
}
#[derive(Serialize, Deserialize, Debug, Eq, PartialEq)]
#[serde(tag = "type", rename_all = "lowercase")]
pub enum ToolCallContent {
Function { function: FunctionContent },
}
#[derive(Serialize, Deserialize, Debug, Eq, PartialEq)]
pub struct FunctionContent {
pub name: String,
pub arguments: String,
}
#[derive(Serialize, Debug)]
pub struct ChatCompletionRequest {
pub model: String,
pub messages: Vec<ChatMessage>,
pub stream: bool,
#[serde(skip_serializing_if = "Option::is_none")]
pub max_tokens: Option<i32>,
#[serde(skip_serializing_if = "Option::is_none")]
pub stop: Option<Vec<String>>,
#[serde(skip_serializing_if = "Option::is_none")]
pub temperature: Option<f32>,
#[serde(skip_serializing_if = "Vec::is_empty")]
pub tools: Vec<ToolDefinition>,
#[serde(skip_serializing_if = "Option::is_none")]
pub tool_choice: Option<ToolChoice>,
}
#[derive(Serialize, Deserialize, Debug)]
pub struct ChatResponse {
pub id: String,
pub object: String,
pub created: u64,
pub model: String,
pub choices: Vec<ChoiceDelta>,
}
#[derive(Serialize, Deserialize, Debug)]
pub struct ChoiceDelta {
pub index: u32,
pub delta: ResponseMessageDelta,
pub finish_reason: Option<String>,
}
#[derive(Serialize, Deserialize, Debug, Eq, PartialEq)]
pub struct ToolCallChunk {
pub index: usize,
pub id: Option<String>,
// There is also an optional `type` field that would determine if a
// function is there. Sometimes this streams in with the `function` before
// it streams in the `type`
pub function: Option<FunctionChunk>,
}
#[derive(Serialize, Deserialize, Debug, Eq, PartialEq)]
pub struct FunctionChunk {
pub name: Option<String>,
pub arguments: Option<String>,
}
#[derive(Serialize, Deserialize, Debug)]
pub struct Usage {
pub prompt_tokens: u64,
pub completion_tokens: u64,
pub total_tokens: u64,
}
#[derive(Debug, Default, Clone, Deserialize, PartialEq)]
#[serde(transparent)]
pub struct Capabilities(Vec<String>);
impl Capabilities {
pub fn supports_tool_calls(&self) -> bool {
self.0.iter().any(|cap| cap == "tool_use")
}
pub fn supports_images(&self) -> bool {
self.0.iter().any(|cap| cap == "vision")
}
}
#[derive(Serialize, Deserialize, Debug)]
#[serde(untagged)]
pub enum ResponseStreamResult {
Ok(ResponseStreamEvent),
Err { error: String },
}
#[derive(Serialize, Deserialize, Debug)]
pub struct ResponseStreamEvent {
pub created: u32,
pub model: String,
pub object: String,
pub choices: Vec<ChoiceDelta>,
pub usage: Option<Usage>,
}
#[derive(Deserialize)]
pub struct ListModelsResponse {
pub data: Vec<ModelEntry>,
}
#[derive(Clone, Debug, Deserialize, PartialEq)]
pub struct ModelEntry {
pub id: String,
pub object: String,
pub r#type: ModelType,
pub publisher: String,
pub arch: Option<String>,
pub compatibility_type: CompatibilityType,
pub quantization: Option<String>,
pub state: ModelState,
pub max_context_length: Option<u64>,
pub loaded_context_length: Option<u64>,
#[serde(default)]
pub capabilities: Capabilities,
}
#[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
#[serde(rename_all = "lowercase")]
pub enum ModelType {
Llm,
Embeddings,
Vlm,
}
#[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
#[serde(rename_all = "kebab-case")]
pub enum ModelState {
Loaded,
Loading,
NotLoaded,
}
#[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
#[serde(rename_all = "lowercase")]
pub enum CompatibilityType {
Gguf,
Mlx,
}
#[derive(Serialize, Deserialize, Debug, Eq, PartialEq)]
pub struct ResponseMessageDelta {
pub role: Option<Role>,
pub content: Option<String>,
#[serde(default, skip_serializing_if = "Option::is_none")]
pub reasoning_content: Option<String>,
#[serde(default, skip_serializing_if = "Option::is_none")]
pub tool_calls: Option<Vec<ToolCallChunk>>,
}
pub async fn complete(
client: &dyn HttpClient,
api_url: &str,
request: ChatCompletionRequest,
) -> Result<ChatResponse> {
let uri = format!("{api_url}/chat/completions");
let request_builder = HttpRequest::builder()
.method(Method::POST)
.uri(uri)
.header("Content-Type", "application/json");
let serialized_request = serde_json::to_string(&request)?;
let request = request_builder.body(AsyncBody::from(serialized_request))?;
let mut response = client.send(request).await?;
if response.status().is_success() {
let mut body = Vec::new();
response.body_mut().read_to_end(&mut body).await?;
let response_message: ChatResponse = serde_json::from_slice(&body)?;
Ok(response_message)
} else {
let mut body = Vec::new();
response.body_mut().read_to_end(&mut body).await?;
let body_str = std::str::from_utf8(&body)?;
anyhow::bail!(
"Failed to connect to API: {} {}",
response.status(),
body_str
);
}
}
pub async fn stream_chat_completion(
client: &dyn HttpClient,
api_url: &str,
request: ChatCompletionRequest,
) -> Result<BoxStream<'static, Result<ResponseStreamEvent>>> {
let uri = format!("{api_url}/chat/completions");
let request_builder = http::Request::builder()
.method(Method::POST)
.uri(uri)
.header("Content-Type", "application/json");
let request = request_builder.body(AsyncBody::from(serde_json::to_string(&request)?))?;
let mut response = client.send(request).await?;
if response.status().is_success() {
let reader = BufReader::new(response.into_body());
Ok(reader
.lines()
.filter_map(|line| async move {
match line {
Ok(line) => {
let line = line.strip_prefix("data: ")?;
if line == "[DONE]" {
None
} else {
let result = serde_json::from_str(&line)
.context("Unable to parse chat completions response");
if let Err(ref e) = result {
eprintln!("Error parsing line: {e}\nLine content: '{line}'");
}
Some(result)
}
}
Err(e) => {
eprintln!("Error reading line: {e}");
Some(Err(e.into()))
}
}
})
.boxed())
} else {
let mut body = String::new();
response.body_mut().read_to_string(&mut body).await?;
anyhow::bail!(
"Failed to connect to LM Studio API: {} {}",
response.status(),
body,
);
}
}
pub async fn get_models(
client: &dyn HttpClient,
api_url: &str,
_: Option<Duration>,
) -> Result<Vec<ModelEntry>> {
let uri = format!("{api_url}/models");
let request_builder = HttpRequest::builder()
.method(Method::GET)
.uri(uri)
.header("Accept", "application/json");
let request = request_builder.body(AsyncBody::default())?;
let mut response = client.send(request).await?;
let mut body = String::new();
response.body_mut().read_to_string(&mut body).await?;
anyhow::ensure!(
response.status().is_success(),
"Failed to connect to LM Studio API: {} {}",
response.status(),
body,
);
let response: ListModelsResponse =
serde_json::from_str(&body).context("Unable to parse LM Studio models response")?;
Ok(response.data)
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_image_message_part_serialization() {
let image_part = MessagePart::Image {
image_url: ImageUrl {
url: "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNkYPhfDwAChwGA60e6kgAAAABJRU5ErkJggg==".to_string(),
detail: None,
},
};
let json = serde_json::to_string(&image_part).unwrap();
println!("Serialized image part: {}", json);
// Verify the structure matches what LM Studio expects
let expected_structure = r#"{"type":"image_url","image_url":{"url":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNkYPhfDwAChwGA60e6kgAAAABJRU5ErkJggg=="}}"#;
assert_eq!(json, expected_structure);
}
#[test]
fn test_text_message_part_serialization() {
let text_part = MessagePart::Text {
text: "Hello, world!".to_string(),
};
let json = serde_json::to_string(&text_part).unwrap();
println!("Serialized text part: {}", json);
let expected_structure = r#"{"type":"text","text":"Hello, world!"}"#;
assert_eq!(json, expected_structure);
}
}