demo: an easy to use catalog loader

crates/catalog/rest/src/catalog.rs

@@ -19,13 +19,14 @@
 
 use std::collections::HashMap;
 use std::str::FromStr;
+use std::sync::Arc;
 
 use async_trait::async_trait;
 use iceberg::io::FileIO;
 use iceberg::table::Table;
 use iceberg::{
-    Catalog, Error, ErrorKind, Namespace, NamespaceIdent, Result, TableCommit, TableCreation,
-    TableIdent,
+    Catalog, CatalogLoader, Error, ErrorKind, Namespace, NamespaceIdent, Result, TableCommit,
+    TableCreation, TableIdent,
 };
 use itertools::Itertools;
 use reqwest::header::{
@@ -320,6 +321,22 @@ impl RestCatalog {
     }
 }
 
+#[async_trait]
+impl CatalogLoader for RestCatalog {
+    async fn load(mut properties: HashMap<String, String>) -> Result<Arc<dyn Catalog>> {
+        let uri = properties
+            .remove("uri")
+            .ok_or_else(|| Error::new(ErrorKind::DataInvalid, "Missing required property `uri`"))?;
+
+        let config = RestCatalogConfig::builder()
+            .uri(uri)
+            .props(properties)
+            .build();
+
+        Ok(Arc::new(RestCatalog::new(config)))
+    }
+}
+
 /// All requests and expected responses are derived from the REST catalog API spec:
 /// https://github.com/apache/iceberg/blob/main/open-api/rest-catalog-open-api.yaml
 #[async_trait]

crates/iceberg/src/catalog/mod.rs

@@ -21,6 +21,7 @@ use std::collections::HashMap;
 use std::fmt::{Debug, Display};
 use std::mem::take;
 use std::ops::Deref;
+use std::sync::Arc;
 
 use _serde::deserialize_snapshot;
 use async_trait::async_trait;
@@ -36,7 +37,19 @@ use crate::spec::{
 use crate::table::Table;
 use crate::{Error, ErrorKind, Result};
 
+/// The CatalogLoader trait is used to load a catalog from a given name and properties.
+#[async_trait]
+pub trait CatalogLoader: Debug + Send + Sync {
+    /// Load a catalog from the given name and properties.
+    async fn load(properties: HashMap<String, String>) -> Result<Arc<dyn Catalog>>;
+}
+
 /// The catalog API for Iceberg Rust.
+///
+/// Users will have two ways to construct a catalog:
+///
+/// - Use `CatalogLoeader` to load a catalog from a name and properties.
+/// - Use `CatalogBuilder` provided by the catalog implementer to build a catalog in a strong typed way.
 #[async_trait]
 pub trait Catalog: Debug + Sync + Send {
     /// List namespaces inside the catalog.
@@ -2091,7 +2104,7 @@ mod tests {
                 {
                     "action": "remove-schemas",
                     "schema-ids": [1, 2]
-                }        
+                }
             "#,
             TableUpdate::RemoveSchemas {
                 schema_ids: vec![1, 2],

crates/iceberg/src/lib.rs

@@ -61,10 +61,9 @@ mod error;
 pub use error::{Error, ErrorKind, Result};
 
 mod catalog;
-
 pub use catalog::{
-    Catalog, Namespace, NamespaceIdent, TableCommit, TableCreation, TableIdent, TableRequirement,
-    TableUpdate, ViewCreation,
+    Catalog, CatalogLoader, Namespace, NamespaceIdent, TableCommit, TableCreation, TableIdent,
+    TableRequirement, TableUpdate, ViewCreation,
 };
 
 pub mod table;