feat(catalog): Implement register_table for glue catalog (#1568)

## Which issue does this PR close?
- Closes #1515.

## What changes are included in this PR?

* implemented the register_table method in the Glue catalog.

* added an integration test to cover table registration via metadata
location.

## Are these changes tested?
Yes
* cargo build
* cargo test (including new test case for register_table)

I'm new to Rust and to Iceberg, any feedback or suggestions for
improvement are very welcome! 😊

Author: Yiyang-C

crates/catalog/glue/src/catalog.rs

@@ -20,6 +20,7 @@ use std::fmt::Debug;
 
 use anyhow::anyhow;
 use async_trait::async_trait;
+use aws_sdk_glue::operation::create_table::CreateTableError;
 use aws_sdk_glue::operation::update_table::UpdateTableError;
 use aws_sdk_glue::types::TableInput;
 use iceberg::io::{
@@ -700,15 +701,67 @@ impl Catalog for GlueCatalog {
         }
     }
 
+    /// registers an existing table into the Glue Catalog.
+    ///
+    /// Converts the provided table identifier and metadata location into a
+    /// Glue-compatible table representation, and attempts to create the
+    /// corresponding table in the Glue Catalog.
+    ///
+    /// # Returns
+    /// Returns `Ok(Table)` if the table is successfully registered and loaded.
+    /// If the registration fails due to validation issues, existing table conflicts,
+    /// metadata problems, or errors during the registration or loading process,
+    /// an `Err(...)` is returned.
     async fn register_table(
         &self,
-        _table_ident: &TableIdent,
-        _metadata_location: String,
+        table_ident: &TableIdent,
+        metadata_location: String,
     ) -> Result<Table> {
-        Err(Error::new(
-            ErrorKind::FeatureUnsupported,
-            "Registering a table is not supported yet",
-        ))
+        let db_name = validate_namespace(table_ident.namespace())?;
+        let table_name = table_ident.name();
+        let metadata = TableMetadata::read_from(&self.file_io, &metadata_location).await?;
+
+        let table_input = convert_to_glue_table(
+            table_name,
+            metadata_location.clone(),
+            &metadata,
+            metadata.properties(),
+            None,
+        )?;
+
+        let builder = self
+            .client
+            .0
+            .create_table()
+            .database_name(&db_name)
+            .table_input(table_input);
+        let builder = with_catalog_id!(builder, self.config);
+
+        builder.send().await.map_err(|e| {
+            let error = e.into_service_error();
+            match error {
+                CreateTableError::EntityNotFoundException(_) => Error::new(
+                    ErrorKind::NamespaceNotFound,
+                    format!("Database {db_name} does not exist"),
+                ),
+                CreateTableError::AlreadyExistsException(_) => Error::new(
+                    ErrorKind::TableAlreadyExists,
+                    format!("Table {table_ident} already exists"),
+                ),
+                _ => Error::new(
+                    ErrorKind::Unexpected,
+                    format!("Failed to register table {table_ident} due to AWS SDK error"),
+                ),
+            }
+            .with_source(anyhow!("aws sdk error: {:?}", error))
+        })?;
+
+        Ok(Table::builder()
+            .identifier(table_ident.clone())
+            .metadata_location(metadata_location)
+            .metadata(metadata)
+            .file_io(self.file_io())
+            .build()?)
     }
 
     async fn update_table(&self, commit: TableCommit) -> Result<Table> {

crates/catalog/glue/tests/glue_catalog_test.rs

@@ -469,3 +469,35 @@ async fn test_update_table() -> Result<()> {
 
     Ok(())
 }
+
+#[tokio::test]
+async fn test_register_table() -> Result<()> {
+    let catalog = get_catalog().await;
+    let namespace = NamespaceIdent::new("test_register_table".into());
+    set_test_namespace(&catalog, &namespace).await?;
+
+    let creation = set_table_creation(
+        Some("s3a://warehouse/hive/test_register_table".into()),
+        "my_table",
+    )?;
+    let table = catalog.create_table(&namespace, creation).await?;
+    let metadata_location = table
+        .metadata_location()
+        .expect("Expected metadata location to be set")
+        .to_string();
+
+    catalog.drop_table(table.identifier()).await?;
+    let ident = TableIdent::new(namespace.clone(), "my_table".to_string());
+
+    let registered = catalog
+        .register_table(&ident, metadata_location.clone())
+        .await?;
+
+    assert_eq!(registered.identifier(), &ident);
+    assert_eq!(
+        registered.metadata_location(),
+        Some(metadata_location.as_str())
+    );
+
+    Ok(())
+}