feat: add user_id field to ClientConfig for user identification (#3240)

## Summary

- Add a `user_id` field to `ClientConfig` that allows users to identify
themselves to LanceDB Cloud/Enterprise
- The user_id is sent as the `x-lancedb-user-id` HTTP header in all
requests
- Supports three configuration methods:
  - Direct assignment via `ClientConfig.user_id`
  - Environment variable `LANCEDB_USER_ID`
  - Indirect env var lookup via `LANCEDB_USER_ID_ENV_KEY`

Closes #3230

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Cargo.lock

@@ -4630,7 +4630,7 @@ dependencies = [
 
 [[package]]
 name = "lancedb"
-version = "0.28.0-beta.0"
+version = "0.28.0-beta.1"
 dependencies = [
  "ahash",
  "anyhow",
@@ -4712,7 +4712,7 @@ dependencies = [
 
 [[package]]
 name = "lancedb-nodejs"
-version = "0.28.0-beta.0"
+version = "0.28.0-beta.1"
 dependencies = [
  "arrow-array",
  "arrow-buffer",
@@ -4734,7 +4734,7 @@ dependencies = [
 
 [[package]]
 name = "lancedb-python"
-version = "0.31.0-beta.0"
+version = "0.31.0-beta.1"
 dependencies = [
  "arrow",
  "async-trait",

docs/src/js/interfaces/ClientConfig.md

@@ -53,3 +53,18 @@ optional tlsConfig: TlsConfig;
 ```ts
 optional userAgent: string;
 ```
+
+***
+
+### userId?
+
+```ts
+optional userId: string;
+```
+
+User identifier for tracking purposes.
+
+This is sent as the `x-lancedb-user-id` header in requests to LanceDB Cloud/Enterprise.
+It can be set directly, or via the `LANCEDB_USER_ID` environment variable.
+Alternatively, set `LANCEDB_USER_ID_ENV_KEY` to specify another environment
+variable that contains the user ID value.

nodejs/package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "@lancedb/lancedb",
-  "version": "0.28.0-beta.0",
+  "version": "0.28.0-beta.1",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@lancedb/lancedb",
-      "version": "0.28.0-beta.0",
+      "version": "0.28.0-beta.1",
       "cpu": [
         "x64",
         "arm64"

nodejs/src/remote.rs

@@ -92,6 +92,13 @@ pub struct ClientConfig {
     pub extra_headers: Option<HashMap<String, String>>,
     pub id_delimiter: Option<String>,
     pub tls_config: Option<TlsConfig>,
+    /// User identifier for tracking purposes.
+    ///
+    /// This is sent as the `x-lancedb-user-id` header in requests to LanceDB Cloud/Enterprise.
+    /// It can be set directly, or via the `LANCEDB_USER_ID` environment variable.
+    /// Alternatively, set `LANCEDB_USER_ID_ENV_KEY` to specify another environment
+    /// variable that contains the user ID value.
+    pub user_id: Option<String>,
 }
 
 impl From<TimeoutConfig> for lancedb::remote::TimeoutConfig {
@@ -145,6 +152,7 @@ impl From<ClientConfig> for lancedb::remote::ClientConfig {
             id_delimiter: config.id_delimiter,
             tls_config: config.tls_config.map(Into::into),
             header_provider: None, // the header provider is set separately later
+            user_id: config.user_id,
         }
     }
 }

python/python/lancedb/remote/__init__.py

@@ -145,6 +145,33 @@ class TlsConfig:
 
 @dataclass
 class ClientConfig:
+    """Configuration for the LanceDB Cloud HTTP client.
+
+    Attributes
+    ----------
+    user_agent: str
+        User agent string sent with requests.
+    retry_config: RetryConfig
+        Configuration for retrying failed requests.
+    timeout_config: Optional[TimeoutConfig]
+        Configuration for request timeouts.
+    extra_headers: Optional[dict]
+        Additional headers to include in requests.
+    id_delimiter: Optional[str]
+        The delimiter to use when constructing object identifiers.
+    tls_config: Optional[TlsConfig]
+        TLS/mTLS configuration for secure connections.
+    header_provider: Optional[HeaderProvider]
+        Provider for dynamic headers to be added to each request.
+    user_id: Optional[str]
+        User identifier for tracking purposes. This is sent as the
+        `x-lancedb-user-id` header in requests to LanceDB Cloud/Enterprise.
+
+        This can also be set via the `LANCEDB_USER_ID` environment variable.
+        Alternatively, set `LANCEDB_USER_ID_ENV_KEY` to specify another
+        environment variable that contains the user ID value.
+    """
+
     user_agent: str = f"LanceDB-Python-Client/{__version__}"
     retry_config: RetryConfig = field(default_factory=RetryConfig)
     timeout_config: Optional[TimeoutConfig] = field(default_factory=TimeoutConfig)
@@ -152,6 +179,7 @@ class ClientConfig:
     id_delimiter: Optional[str] = None
     tls_config: Optional[TlsConfig] = None
     header_provider: Optional["HeaderProvider"] = None
+    user_id: Optional[str] = None
 
     def __post_init__(self):
         if isinstance(self.retry_config, dict):

python/src/connection.rs

@@ -547,6 +547,7 @@ pub struct PyClientConfig {
     id_delimiter: Option<String>,
     tls_config: Option<PyClientTlsConfig>,
     header_provider: Option<Py<PyAny>>,
+    user_id: Option<String>,
 }
 
 #[derive(FromPyObject)]
@@ -631,6 +632,7 @@ impl From<PyClientConfig> for lancedb::remote::ClientConfig {
             id_delimiter: value.id_delimiter,
             tls_config: value.tls_config.map(Into::into),
             header_provider,
+            user_id: value.user_id,
         }
     }
 }

rust/lancedb/src/remote/client.rs

@@ -52,6 +52,13 @@ pub struct ClientConfig {
     pub tls_config: Option<TlsConfig>,
     /// Provider for custom headers to be added to each request
     pub header_provider: Option<Arc<dyn HeaderProvider>>,
+    /// User identifier for tracking purposes.
+    ///
+    /// This is sent as the `x-lancedb-user-id` header in requests to LanceDB Cloud/Enterprise.
+    /// It can be set directly, or via the `LANCEDB_USER_ID` environment variable.
+    /// Alternatively, set `LANCEDB_USER_ID_ENV_KEY` to specify another environment
+    /// variable that contains the user ID value.
+    pub user_id: Option<String>,
 }
 
 impl std::fmt::Debug for ClientConfig {
@@ -67,6 +74,7 @@ impl std::fmt::Debug for ClientConfig {
                 "header_provider",
                 &self.header_provider.as_ref().map(|_| "Some(...)"),
             )
+            .field("user_id", &self.user_id)
             .finish()
     }
 }
@@ -81,10 +89,41 @@ impl Default for ClientConfig {
             id_delimiter: None,
             tls_config: None,
             header_provider: None,
+            user_id: None,
         }
     }
 }
 
+impl ClientConfig {
+    /// Resolve the user ID from the config or environment variables.
+    ///
+    /// Resolution order:
+    /// 1. If `user_id` is set in the config, use that value
+    /// 2. If `LANCEDB_USER_ID` environment variable is set, use that value
+    /// 3. If `LANCEDB_USER_ID_ENV_KEY` is set, read the env var it points to
+    /// 4. Otherwise, return None
+    pub fn resolve_user_id(&self) -> Option<String> {
+        if self.user_id.is_some() {
+            return self.user_id.clone();
+        }
+
+        if let Ok(user_id) = std::env::var("LANCEDB_USER_ID")
+            && !user_id.is_empty()
+        {
+            return Some(user_id);
+        }
+
+        if let Ok(env_key) = std::env::var("LANCEDB_USER_ID_ENV_KEY")
+            && let Ok(user_id) = std::env::var(&env_key)
+            && !user_id.is_empty()
+        {
+            return Some(user_id);
+        }
+
+        None
+    }
+}
+
 /// How to handle timeouts for HTTP requests.
 #[derive(Clone, Default, Debug)]
 pub struct TimeoutConfig {
@@ -464,6 +503,15 @@ impl<S: HttpSend> RestfulLanceDbClient<S> {
             );
         }
 
+        if let Some(user_id) = config.resolve_user_id() {
+            headers.insert(
+                HeaderName::from_static("x-lancedb-user-id"),
+                HeaderValue::from_str(&user_id).map_err(|_| Error::InvalidInput {
+                    message: format!("non-ascii user_id '{}' provided", user_id),
+                })?,
+            );
+        }
+
         Ok(headers)
     }
 
@@ -1072,4 +1120,91 @@ mod tests {
             _ => panic!("Expected Runtime error"),
         }
     }
+
+    #[test]
+    fn test_resolve_user_id_direct_value() {
+        let config = ClientConfig {
+            user_id: Some("direct-user-id".to_string()),
+            ..Default::default()
+        };
+        assert_eq!(config.resolve_user_id(), Some("direct-user-id".to_string()));
+    }
+
+    #[test]
+    fn test_resolve_user_id_none() {
+        let config = ClientConfig::default();
+        // Clear env vars that might be set from other tests
+        // SAFETY: This is only called in tests
+        unsafe {
+            std::env::remove_var("LANCEDB_USER_ID");
+            std::env::remove_var("LANCEDB_USER_ID_ENV_KEY");
+        }
+        assert_eq!(config.resolve_user_id(), None);
+    }
+
+    #[test]
+    fn test_resolve_user_id_from_env() {
+        // SAFETY: This is only called in tests
+        unsafe {
+            std::env::set_var("LANCEDB_USER_ID", "env-user-id");
+        }
+        let config = ClientConfig::default();
+        assert_eq!(config.resolve_user_id(), Some("env-user-id".to_string()));
+        // SAFETY: This is only called in tests
+        unsafe {
+            std::env::remove_var("LANCEDB_USER_ID");
+        }
+    }
+
+    #[test]
+    fn test_resolve_user_id_from_env_key() {
+        // SAFETY: This is only called in tests
+        unsafe {
+            std::env::remove_var("LANCEDB_USER_ID");
+            std::env::set_var("LANCEDB_USER_ID_ENV_KEY", "MY_CUSTOM_USER_ID");
+            std::env::set_var("MY_CUSTOM_USER_ID", "custom-env-user-id");
+        }
+        let config = ClientConfig::default();
+        assert_eq!(
+            config.resolve_user_id(),
+            Some("custom-env-user-id".to_string())
+        );
+        // SAFETY: This is only called in tests
+        unsafe {
+            std::env::remove_var("LANCEDB_USER_ID_ENV_KEY");
+            std::env::remove_var("MY_CUSTOM_USER_ID");
+        }
+    }
+
+    #[test]
+    fn test_resolve_user_id_direct_takes_precedence() {
+        // SAFETY: This is only called in tests
+        unsafe {
+            std::env::set_var("LANCEDB_USER_ID", "env-user-id");
+        }
+        let config = ClientConfig {
+            user_id: Some("direct-user-id".to_string()),
+            ..Default::default()
+        };
+        assert_eq!(config.resolve_user_id(), Some("direct-user-id".to_string()));
+        // SAFETY: This is only called in tests
+        unsafe {
+            std::env::remove_var("LANCEDB_USER_ID");
+        }
+    }
+
+    #[test]
+    fn test_resolve_user_id_empty_env_ignored() {
+        // SAFETY: This is only called in tests
+        unsafe {
+            std::env::set_var("LANCEDB_USER_ID", "");
+            std::env::remove_var("LANCEDB_USER_ID_ENV_KEY");
+        }
+        let config = ClientConfig::default();
+        assert_eq!(config.resolve_user_id(), None);
+        // SAFETY: This is only called in tests
+        unsafe {
+            std::env::remove_var("LANCEDB_USER_ID");
+        }
+    }
 }