zeroclaw/src/providers/gemini.rs

560 lines
18 KiB
Rust

//! Google Gemini provider with support for:
//! - Direct API key (`GEMINI_API_KEY` env var or config)
//! - Gemini CLI OAuth tokens (reuse existing ~/.gemini/ authentication)
//! - Google Cloud ADC (`GOOGLE_APPLICATION_CREDENTIALS`)
use crate::providers::traits::Provider;
use async_trait::async_trait;
use directories::UserDirs;
use reqwest::Client;
use serde::{Deserialize, Serialize};
use std::path::PathBuf;
/// Gemini provider supporting multiple authentication methods.
pub struct GeminiProvider {
auth: Option<GeminiAuth>,
client: Client,
}
/// Resolved credential — the variant determines both the HTTP auth method
/// and the diagnostic label returned by `auth_source()`.
#[derive(Debug)]
enum GeminiAuth {
/// Explicit API key from config: sent as `?key=` query parameter.
ExplicitKey(String),
/// API key from `GEMINI_API_KEY` env var: sent as `?key=`.
EnvGeminiKey(String),
/// API key from `GOOGLE_API_KEY` env var: sent as `?key=`.
EnvGoogleKey(String),
/// OAuth access token from Gemini CLI: sent as `Authorization: Bearer`.
OAuthToken(String),
}
impl GeminiAuth {
/// Whether this credential is an API key (sent as `?key=` query param).
fn is_api_key(&self) -> bool {
matches!(
self,
GeminiAuth::ExplicitKey(_) | GeminiAuth::EnvGeminiKey(_) | GeminiAuth::EnvGoogleKey(_)
)
}
/// The raw credential string.
fn credential(&self) -> &str {
match self {
GeminiAuth::ExplicitKey(s)
| GeminiAuth::EnvGeminiKey(s)
| GeminiAuth::EnvGoogleKey(s)
| GeminiAuth::OAuthToken(s) => s,
}
}
}
// ══════════════════════════════════════════════════════════════════════════════
// API REQUEST/RESPONSE TYPES
// ══════════════════════════════════════════════════════════════════════════════
#[derive(Debug, Serialize)]
struct GenerateContentRequest {
contents: Vec<Content>,
#[serde(skip_serializing_if = "Option::is_none")]
system_instruction: Option<Content>,
#[serde(rename = "generationConfig")]
generation_config: GenerationConfig,
}
#[derive(Debug, Serialize)]
struct Content {
#[serde(skip_serializing_if = "Option::is_none")]
role: Option<String>,
parts: Vec<Part>,
}
#[derive(Debug, Serialize)]
struct Part {
text: String,
}
#[derive(Debug, Serialize)]
struct GenerationConfig {
temperature: f64,
#[serde(rename = "maxOutputTokens")]
max_output_tokens: u32,
}
#[derive(Debug, Deserialize)]
struct GenerateContentResponse {
candidates: Option<Vec<Candidate>>,
error: Option<ApiError>,
}
#[derive(Debug, Deserialize)]
struct Candidate {
content: CandidateContent,
}
#[derive(Debug, Deserialize)]
struct CandidateContent {
parts: Vec<ResponsePart>,
}
#[derive(Debug, Deserialize)]
struct ResponsePart {
text: Option<String>,
}
#[derive(Debug, Deserialize)]
struct ApiError {
message: String,
}
// ══════════════════════════════════════════════════════════════════════════════
// GEMINI CLI TOKEN STRUCTURES
// ══════════════════════════════════════════════════════════════════════════════
/// OAuth token stored by Gemini CLI in `~/.gemini/oauth_creds.json`
#[derive(Debug, Deserialize)]
struct GeminiCliOAuthCreds {
access_token: Option<String>,
expiry: Option<String>,
}
impl GeminiProvider {
/// Create a new Gemini provider.
///
/// Authentication priority:
/// 1. Explicit API key passed in
/// 2. `GEMINI_API_KEY` environment variable
/// 3. `GOOGLE_API_KEY` environment variable
/// 4. Gemini CLI OAuth tokens (`~/.gemini/oauth_creds.json`)
pub fn new(api_key: Option<&str>) -> Self {
let resolved_auth = api_key
.and_then(Self::normalize_non_empty)
.map(GeminiAuth::ExplicitKey)
.or_else(|| Self::load_non_empty_env("GEMINI_API_KEY").map(GeminiAuth::EnvGeminiKey))
.or_else(|| Self::load_non_empty_env("GOOGLE_API_KEY").map(GeminiAuth::EnvGoogleKey))
.or_else(|| Self::try_load_gemini_cli_token().map(GeminiAuth::OAuthToken));
Self {
auth: resolved_auth,
client: Client::builder()
.timeout(std::time::Duration::from_secs(120))
.connect_timeout(std::time::Duration::from_secs(10))
.build()
.unwrap_or_else(|_| Client::new()),
}
}
fn normalize_non_empty(value: &str) -> Option<String> {
let trimmed = value.trim();
if trimmed.is_empty() {
None
} else {
Some(trimmed.to_string())
}
}
fn load_non_empty_env(name: &str) -> Option<String> {
std::env::var(name)
.ok()
.and_then(|value| Self::normalize_non_empty(&value))
}
/// Try to load OAuth access token from Gemini CLI's cached credentials.
/// Location: `~/.gemini/oauth_creds.json`
fn try_load_gemini_cli_token() -> Option<String> {
let gemini_dir = Self::gemini_cli_dir()?;
let creds_path = gemini_dir.join("oauth_creds.json");
if !creds_path.exists() {
return None;
}
let content = std::fs::read_to_string(&creds_path).ok()?;
let creds: GeminiCliOAuthCreds = serde_json::from_str(&content).ok()?;
// Check if token is expired (basic check)
if let Some(ref expiry) = creds.expiry {
if let Ok(expiry_time) = chrono::DateTime::parse_from_rfc3339(expiry) {
if expiry_time < chrono::Utc::now() {
tracing::warn!("Gemini CLI OAuth token expired — re-run `gemini` to refresh");
return None;
}
}
}
creds
.access_token
.and_then(|token| Self::normalize_non_empty(&token))
}
/// Get the Gemini CLI config directory (~/.gemini)
fn gemini_cli_dir() -> Option<PathBuf> {
UserDirs::new().map(|u| u.home_dir().join(".gemini"))
}
/// Check if Gemini CLI is configured and has valid credentials
pub fn has_cli_credentials() -> bool {
Self::try_load_gemini_cli_token().is_some()
}
/// Check if any Gemini authentication is available
pub fn has_any_auth() -> bool {
Self::load_non_empty_env("GEMINI_API_KEY").is_some()
|| Self::load_non_empty_env("GOOGLE_API_KEY").is_some()
|| Self::has_cli_credentials()
}
/// Get authentication source description for diagnostics.
/// Uses the stored enum variant — no env var re-reading at call time.
pub fn auth_source(&self) -> &'static str {
match self.auth.as_ref() {
Some(GeminiAuth::ExplicitKey(_)) => "config",
Some(GeminiAuth::EnvGeminiKey(_)) => "GEMINI_API_KEY env var",
Some(GeminiAuth::EnvGoogleKey(_)) => "GOOGLE_API_KEY env var",
Some(GeminiAuth::OAuthToken(_)) => "Gemini CLI OAuth",
None => "none",
}
}
fn format_model_name(model: &str) -> String {
if model.starts_with("models/") {
model.to_string()
} else {
format!("models/{model}")
}
}
fn build_generate_content_url(model: &str, auth: &GeminiAuth) -> String {
let model_name = Self::format_model_name(model);
let base_url = format!(
"https://generativelanguage.googleapis.com/v1beta/{model_name}:generateContent"
);
if auth.is_api_key() {
format!("{base_url}?key={}", auth.credential())
} else {
base_url
}
}
fn build_generate_content_request(
&self,
auth: &GeminiAuth,
url: &str,
request: &GenerateContentRequest,
) -> reqwest::RequestBuilder {
let req = self.client.post(url).json(request);
match auth {
GeminiAuth::OAuthToken(token) => req.bearer_auth(token),
_ => req,
}
}
}
#[async_trait]
impl Provider for GeminiProvider {
async fn chat_with_system(
&self,
system_prompt: Option<&str>,
message: &str,
model: &str,
temperature: f64,
) -> anyhow::Result<String> {
let auth = self.auth.as_ref().ok_or_else(|| {
anyhow::anyhow!(
"Gemini API key not found. Options:\n\
1. Set GEMINI_API_KEY env var\n\
2. Run `gemini` CLI to authenticate (tokens will be reused)\n\
3. Get an API key from https://aistudio.google.com/app/apikey\n\
4. Run `zeroclaw onboard` to configure"
)
})?;
// Build request
let system_instruction = system_prompt.map(|sys| Content {
role: None,
parts: vec![Part {
text: sys.to_string(),
}],
});
let request = GenerateContentRequest {
contents: vec![Content {
role: Some("user".to_string()),
parts: vec![Part {
text: message.to_string(),
}],
}],
system_instruction,
generation_config: GenerationConfig {
temperature,
max_output_tokens: 8192,
},
};
let url = Self::build_generate_content_url(model, auth);
let response = self
.build_generate_content_request(auth, &url, &request)
.send()
.await?;
if !response.status().is_success() {
let status = response.status();
let error_text = response.text().await.unwrap_or_default();
anyhow::bail!("Gemini API error ({status}): {error_text}");
}
let result: GenerateContentResponse = response.json().await?;
// Check for API error in response body
if let Some(err) = result.error {
anyhow::bail!("Gemini API error: {}", err.message);
}
// Extract text from response
result
.candidates
.and_then(|c| c.into_iter().next())
.and_then(|c| c.content.parts.into_iter().next())
.and_then(|p| p.text)
.ok_or_else(|| anyhow::anyhow!("No response from Gemini"))
}
}
#[cfg(test)]
mod tests {
use super::*;
use reqwest::header::AUTHORIZATION;
#[test]
fn normalize_non_empty_trims_and_filters() {
assert_eq!(
GeminiProvider::normalize_non_empty(" value "),
Some("value".into())
);
assert_eq!(GeminiProvider::normalize_non_empty(""), None);
assert_eq!(GeminiProvider::normalize_non_empty(" \t\n"), None);
}
#[test]
fn provider_creates_without_key() {
let provider = GeminiProvider::new(None);
// May pick up env vars; just verify it doesn't panic
let _ = provider.auth_source();
}
#[test]
fn provider_creates_with_key() {
let provider = GeminiProvider::new(Some("test-api-key"));
assert!(matches!(
provider.auth,
Some(GeminiAuth::ExplicitKey(ref key)) if key == "test-api-key"
));
}
#[test]
fn provider_rejects_empty_key() {
let provider = GeminiProvider::new(Some(""));
assert!(!matches!(provider.auth, Some(GeminiAuth::ExplicitKey(_))));
}
#[test]
fn gemini_cli_dir_returns_path() {
let dir = GeminiProvider::gemini_cli_dir();
// Should return Some on systems with home dir
if UserDirs::new().is_some() {
assert!(dir.is_some());
assert!(dir.unwrap().ends_with(".gemini"));
}
}
#[test]
fn auth_source_explicit_key() {
let provider = GeminiProvider {
auth: Some(GeminiAuth::ExplicitKey("key".into())),
client: Client::new(),
};
assert_eq!(provider.auth_source(), "config");
}
#[test]
fn auth_source_none_without_credentials() {
let provider = GeminiProvider {
auth: None,
client: Client::new(),
};
assert_eq!(provider.auth_source(), "none");
}
#[test]
fn auth_source_oauth() {
let provider = GeminiProvider {
auth: Some(GeminiAuth::OAuthToken("ya29.mock".into())),
client: Client::new(),
};
assert_eq!(provider.auth_source(), "Gemini CLI OAuth");
}
#[test]
fn model_name_formatting() {
assert_eq!(
GeminiProvider::format_model_name("gemini-2.0-flash"),
"models/gemini-2.0-flash"
);
assert_eq!(
GeminiProvider::format_model_name("models/gemini-1.5-pro"),
"models/gemini-1.5-pro"
);
}
#[test]
fn api_key_url_includes_key_query_param() {
let auth = GeminiAuth::ExplicitKey("api-key-123".into());
let url = GeminiProvider::build_generate_content_url("gemini-2.0-flash", &auth);
assert!(url.contains(":generateContent?key=api-key-123"));
}
#[test]
fn oauth_url_omits_key_query_param() {
let auth = GeminiAuth::OAuthToken("ya29.test-token".into());
let url = GeminiProvider::build_generate_content_url("gemini-2.0-flash", &auth);
assert!(url.ends_with(":generateContent"));
assert!(!url.contains("?key="));
}
#[test]
fn oauth_request_uses_bearer_auth_header() {
let provider = GeminiProvider {
auth: Some(GeminiAuth::OAuthToken("ya29.mock-token".into())),
client: Client::new(),
};
let auth = GeminiAuth::OAuthToken("ya29.mock-token".into());
let url = GeminiProvider::build_generate_content_url("gemini-2.0-flash", &auth);
let body = GenerateContentRequest {
contents: vec![Content {
role: Some("user".into()),
parts: vec![Part {
text: "hello".into(),
}],
}],
system_instruction: None,
generation_config: GenerationConfig {
temperature: 0.7,
max_output_tokens: 8192,
},
};
let request = provider
.build_generate_content_request(&auth, &url, &body)
.build()
.unwrap();
assert_eq!(
request
.headers()
.get(AUTHORIZATION)
.and_then(|h| h.to_str().ok()),
Some("Bearer ya29.mock-token")
);
}
#[test]
fn api_key_request_does_not_set_bearer_header() {
let provider = GeminiProvider {
auth: Some(GeminiAuth::ExplicitKey("api-key-123".into())),
client: Client::new(),
};
let auth = GeminiAuth::ExplicitKey("api-key-123".into());
let url = GeminiProvider::build_generate_content_url("gemini-2.0-flash", &auth);
let body = GenerateContentRequest {
contents: vec![Content {
role: Some("user".into()),
parts: vec![Part {
text: "hello".into(),
}],
}],
system_instruction: None,
generation_config: GenerationConfig {
temperature: 0.7,
max_output_tokens: 8192,
},
};
let request = provider
.build_generate_content_request(&auth, &url, &body)
.build()
.unwrap();
assert!(request.headers().get(AUTHORIZATION).is_none());
}
#[test]
fn request_serialization() {
let request = GenerateContentRequest {
contents: vec![Content {
role: Some("user".to_string()),
parts: vec![Part {
text: "Hello".to_string(),
}],
}],
system_instruction: Some(Content {
role: None,
parts: vec![Part {
text: "You are helpful".to_string(),
}],
}),
generation_config: GenerationConfig {
temperature: 0.7,
max_output_tokens: 8192,
},
};
let json = serde_json::to_string(&request).unwrap();
assert!(json.contains("\"role\":\"user\""));
assert!(json.contains("\"text\":\"Hello\""));
assert!(json.contains("\"temperature\":0.7"));
assert!(json.contains("\"maxOutputTokens\":8192"));
}
#[test]
fn response_deserialization() {
let json = r#"{
"candidates": [{
"content": {
"parts": [{"text": "Hello there!"}]
}
}]
}"#;
let response: GenerateContentResponse = serde_json::from_str(json).unwrap();
assert!(response.candidates.is_some());
let text = response
.candidates
.unwrap()
.into_iter()
.next()
.unwrap()
.content
.parts
.into_iter()
.next()
.unwrap()
.text;
assert_eq!(text, Some("Hello there!".to_string()));
}
#[test]
fn error_response_deserialization() {
let json = r#"{
"error": {
"message": "Invalid API key"
}
}"#;
let response: GenerateContentResponse = serde_json::from_str(json).unwrap();
assert!(response.error.is_some());
assert_eq!(response.error.unwrap().message, "Invalid API key");
}
}