DerGut commented on code in PR #3000: URL: https://github.com/apache/iceberg-rust/pull/3000#discussion_r3812825543
########## crates/integrations/datafusion/src/catalog_access.rs: ########## @@ -0,0 +1,192 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +use std::collections::HashMap; +use std::sync::Arc; + +use async_trait::async_trait; +use datafusion::catalog::Session; +use datafusion::error::Result as DFResult; +use iceberg::table::Table; +use iceberg::{ + Catalog, Namespace, NamespaceIdent, Result, SessionCatalog, SessionContext, TableCommit, + TableCreation, TableIdent, +}; + +use crate::SessionContextResolver; + +/// Describes how the DataFusion integration accesses an Iceberg catalog. +/// +/// A catalog can either be accessed directly through [`Catalog`] or through a +/// [`SessionCatalog`] bound to an Iceberg [`SessionContext`]. Operations that +/// receive a DataFusion session resolve and bind its context once. Operations +/// for which DataFusion provides no session reuse one anonymous fallback +/// context so session-scoped catalog state remains stable across those calls. +#[derive(Clone, Debug)] +pub(crate) enum CatalogAccess { + /// A catalog accessed directly through the [`Catalog`] API. + Direct(Arc<dyn Catalog>), + + /// A session-aware catalog, its resolver, and the stable context used by + /// DataFusion APIs that do not expose a session. + SessionAware { + catalog: Arc<dyn SessionCatalog>, + resolver: Arc<dyn SessionContextResolver>, + fallback_context: SessionContext, + }, +} + +impl CatalogAccess { + pub(crate) fn with_session(&self, session: &dyn Session) -> DFResult<Arc<dyn Catalog>> { Review Comment: On 1.: Sounds good, I'll create a follow-up! On 2.: I would like for users to just provide a single parameter but I think the more fitting design depends on what users actually use as a `SessionCatalog`. If users are implementing their own `SessionCatalog`, your approach might be easier. They just add another method to their existing type to make it implement the new trait. My current version is based on the assumption that the vast majority of users will use a `RestSessionCatalog`. If we ask users to provide a `DataFusionCatalog` instead, they will have to provide a `dyn SessionCatalog` and a `dyn SessionContextResolver` to some wrapper type we provide, causing them to go through one layer of indirection. ```rust IcebergCatalogProvider::try_new(DataFusionCatalogAdapter::new(rest_session_catalog, my_context_resolver)); ``` Both approaches will work, but I feel like we should be optimizing for the more common one. My opinion might be biased by our internal usage. Do you have a better assessment of how frequently the community uses custom non-REST catalog implementations? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
