Adds set_catalog and current_catalog to session

Author: rchowell

daft/session.py

@@ -68,9 +68,9 @@ def create_catalog(self, name: str) -> Catalog:
         """Create a new catalog scoped to this session."""
         return self._session.create_catalog(name)
 
-    def create_namespace(self, name: str) -> Namespace:
-        """Create a new namespace scope to this session's current catalog."""
-        return self._session.create_namespace(name)
+    # def create_namespace(self, name: str) -> Namespace:
+    #     """Create a new namespace scope to this session's current catalog."""
+    #     return self._session.create_namespace(name)
 
     def create_table(self, name: str, source: TableSource = None) -> Table:
         """Creates a new table scoped to this session's current catalog and namespace."""
@@ -90,9 +90,9 @@ def current_catalog(self) -> Catalog:
         """Returns the session's current catalog."""
         return self._session.current_catalog()
 
-    def current_namespace(self) -> Namespace:
-        """Returns the session's current namespace."""
-        return self._session.current_namespace()
+    # def current_namespace(self) -> Namespace:
+    #     """Returns the session's current namespace."""
+    #     return self._session.current_namespace()
 
     ###
     # get_*

src/daft-catalog/src/catalog.rs

@@ -50,6 +50,11 @@ impl Catalogs {
             .map(|k| k.to_string())
             .collect()
     }
+
+    /// Returns true iff there are no catalogs in this collection.
+    pub fn is_empty(&self) -> bool {
+        self.0.is_empty()
+    }
 }
 
 /// A catalog provides object metadata such as namespaces, tables, and functions.

src/daft-catalog/src/python.rs

@@ -2,7 +2,8 @@ use std::sync::Arc;
 
 use pyo3::{exceptions::PyIndexError, prelude::*};
 
-use crate::{Catalog, Identifier};
+use crate::{Catalog, Identifier, Table};
+use crate::error::{Error,Result};
 
 /// PyCatalog implements the Catalog ABC for some Catalog trait impl (rust->py).
 #[pyclass]
@@ -36,7 +37,7 @@ impl Catalog for PyCatalogImpl {
         todo!()
     }
 
-    fn get_table(&self, _name: &Identifier) -> crate::error::Result<Option<Box<dyn crate::Table>>> {
+    fn get_table(&self, _name: &Identifier) -> Result<Option<Box<dyn Table>>> {
         todo!()
     }
 

src/daft-session/src/python.rs

@@ -29,13 +29,11 @@ impl PySession {
     }
 
     pub fn attach(&self, catalog: PyObject, alias: String) -> PyResult<()> {
-        self.0.attach(Arc::new(PyCatalogImpl::from(catalog)), alias)?;
-        Ok(())
+        Ok(self.0.attach(Arc::new(PyCatalogImpl::from(catalog)), alias)?)
     }
 
     pub fn detach(&self, catalog: &str) -> PyResult<()> {
-        self.0.detach(catalog)?;
-        Ok(())
+        Ok(self.0.detach(catalog)?)
     }
 
     pub fn create_catalog(&self, name: &str) -> PyResult<PyCatalog> {
@@ -56,7 +54,6 @@ impl PySession {
             let catalog = catalog.to_py(py);
             Ok(catalog)
         })
-
     }
 
     pub fn get_namespace(&self, name: &str) -> Namespace {
@@ -67,27 +64,28 @@ impl PySession {
         todo!()
     }
 
+    #[pyo3(signature = (pattern=None))]
     pub fn list_catalogs(&self, pattern: Option<&str>) -> PyResult<Vec<String>> {
-        let catalogs = self.0.list_catalogs(pattern)?;
-        Ok(catalogs)
+        Ok(self.0.list_catalogs(pattern)?)
     }
 
+    #[pyo3(signature = (pattern=None))]
     pub fn list_namespaces(&self, pattern: Option<&str>) -> PyResult<()> {
         todo!()
     }
 
+    #[pyo3(signature = (pattern=None))]
     pub fn list_tables(&self, pattern: Option<&str>) -> PyResult<()> {
         todo!()
     }
 
-    pub fn set_catalog(&self, name: &str) {
-        todo!()
+    pub fn set_catalog(&self, name: &str) -> PyResult<()> {
+        Ok(self.0.set_catalog(name)?)
     }
 
-    pub fn set_namespace(&self, name: &str) {
+    pub fn set_namespace(&self, name: String) {
         todo!()
     }
-
 }
 
 pub fn register_modules(parent: &Bound<PyModule>) -> PyResult<()> {

src/daft-session/src/session.rs

@@ -92,7 +92,7 @@ impl Session {
 
     /// Returns the session's current catalog.
     pub fn current_catalog(&self) -> Result<Arc<dyn Catalog>> {
-        todo!()
+        self.get_catalog(&self.state().options.curr_catalog)
     }
 
     /// Returns the session's current schema.
@@ -120,19 +120,35 @@ impl Session {
         obj_not_found_err!("Table", name)
     }
 
-    /// Returns true iff the session has for the given identifier
+    /// Returns true iff the session has access to a matching catalog.
+    pub fn has_catalog(&self, name: &str) -> bool {
+        self.state().catalogs.exists(name)
+    }
+
+    /// Returns true iff the session has access to a matching table.
     pub fn has_table(&self, name: &Identifier) -> bool {
         if name.has_namespace() {
             return false;
         }
         return self.state().tables.contains_key(&name.name);
     }
 
+    /// Lists all catalogs matching the pattern.
     pub fn list_catalogs(&self, pattern: Option<&str>) -> Result<Vec<String>> {
         Ok(self.state().catalogs.list(pattern))
     }
+
+    /// Sets the current_catalog
+    pub fn set_catalog(&self, name: &str) -> Result<()> {
+        if !self.has_catalog(name) {
+            obj_not_found_err!("Catalog", &name.into())
+        }
+        self.state_mut().options.curr_catalog = name.to_string();
+        Ok(())
+    }
 }
 
+
 impl Default for Session {
     fn default() -> Self {
         Self::empty()

tests/test_session.py

@@ -1,9 +1,78 @@
 import daft
+from daft.session import Session
 
-###
-# SESSION SETUP
-###
+import pytest
 
+"""
+SESSION SETUP
+"""
 
 def test_current_session_exists():
     assert daft.current_session() is not None
+
+"""
+ATTACH & DETACH
+"""
+
+def test_attach():
+    sess = Session.empty()
+    #
+    # create some 'existing' catalogs
+    cat1 = daft.load_catalog("cat1")
+    cat2 = daft.load_catalog("cat2")
+    #
+    # attach them..
+    sess.attach(cat1)
+    sess.attach(cat2)
+    #
+    # list_catalogs
+    assert 2 == len(sess.list_catalogs())
+    #
+    # get_catalog
+    assert sess.get_catalog("cat1") == cat1
+    assert sess.get_catalog("cat2") == cat2
+    #
+    # error!
+    with pytest.raises(Exception, match="already exists"):
+        sess.attach(cat1)
+
+def test_detach():
+    sess = Session.empty()
+    #
+    # setup.
+    cat1 = daft.load_catalog("cat1")
+    cat2 = daft.load_catalog("cat2")
+    sess.attach(cat1)
+    sess.attach(cat2)
+    #
+    # 
+    assert 2 == len(sess.list_catalogs())
+    #
+    # detach existing
+    sess.detach("cat1")
+    assert 1 == len(sess.list_catalogs())
+    #
+    # error!
+    with pytest.raises(Exception, match="not found"):
+        sess.detach("cat1")
+
+"""
+CATALOG ACTIONS
+"""
+
+@pytest.mark.skip
+def test_catalog_actions():
+    sess = Session.empty()
+    #
+    # setup.
+    cat1 = daft.load_catalog("cat1")
+    cat2 = daft.load_catalog("cat2")
+    sess.attach(cat1)
+    sess.attach(cat2)
+    #
+    # current_catalog should default to first in.
+    assert cat1 == sess.current_catalog()
+    #
+    # set_catalog and current_catalog
+    sess.set_catalog("cat2")
+    assert cat2 == sess.current_catalog()