fix: using test data sample for catalog example

ci/scripts/rust_example.sh

@@ -27,9 +27,6 @@ for filename in $files
 do
   example_name=`basename $filename ".rs"`
   # Skip tests that rely on external storage and flight
-  # todo: Currently, catalog.rs is placed in the external-dependence directory because there is a problem parsing
-  # the parquet file of the external parquet-test that it currently relies on.
-  # We will wait for this issue[https://github.com/apache/arrow-datafusion/issues/8041] to be resolved.
   if [ ! -d $filename ]; then
      cargo run --example $example_name
   fi

datafusion-examples/Cargo.toml

@@ -41,10 +41,6 @@ path = "examples/flight/flight_server.rs"
 name = "flight_client"
 path = "examples/flight/flight_client.rs"
 
-[[example]]
-name = "catalog"
-path = "examples/external_dependency/catalog.rs"
-
 [[example]]
 name = "dataframe_to_s3"
 path = "examples/external_dependency/dataframe-to-s3.rs"

datafusion-examples/examples/external_dependency/catalog.rs → datafusion-examples/examples/catalog.rs

@@ -16,9 +16,6 @@
 // under the License.
 
 //! Simple example of a catalog/schema implementation.
-//!
-//! Example requires git submodules to be initialized in repo as it uses data from
-//! the `parquet-testing` repo.
 use async_trait::async_trait;
 use datafusion::{
     arrow::util::pretty,
@@ -27,7 +24,7 @@ use datafusion::{
         {CatalogProvider, CatalogProviderList},
     },
     datasource::{
-        file_format::{csv::CsvFormat, parquet::ParquetFormat, FileFormat},
+        file_format::{csv::CsvFormat, FileFormat},
         listing::{ListingOptions, ListingTable, ListingTableConfig, ListingTableUrl},
         TableProvider,
     },
@@ -36,94 +33,102 @@ use datafusion::{
     prelude::SessionContext,
 };
 use std::sync::RwLock;
-use std::{
-    any::Any,
-    collections::HashMap,
-    path::{Path, PathBuf},
-    sync::Arc,
-};
+use std::{any::Any, collections::HashMap, path::Path, sync::Arc};
+use std::{fs::File, io::Write};
+use tempfile::TempDir;
 
 #[tokio::main]
 async fn main() -> Result<()> {
-    let repo_dir = std::fs::canonicalize(
-        PathBuf::from(env!("CARGO_MANIFEST_DIR"))
-            // parent dir of datafusion-examples = repo root
-            .join(".."),
-    )
-    .unwrap();
+    env_logger::builder()
+        .filter_level(log::LevelFilter::Info)
+        .init();
+
+    // Prepare test directories containing multiple files
+    let dir_a = prepare_example_data()?;
+    let dir_b = prepare_example_data()?;
+
     let mut ctx = SessionContext::new();
     let state = ctx.state();
     let catlist = Arc::new(CustomCatalogProviderList::new());
+
     // use our custom catalog list for context. each context has a single catalog list.
     // context will by default have [`MemoryCatalogProviderList`]
     ctx.register_catalog_list(catlist.clone());
 
     // initialize our catalog and schemas
     let catalog = DirCatalog::new();
-    let parquet_schema = DirSchema::create(
+    let schema_a = DirSchema::create(
         &state,
         DirSchemaOpts {
-            format: Arc::new(ParquetFormat::default()),
-            dir: &repo_dir.join("parquet-testing").join("data"),
-            ext: "parquet",
+            format: Arc::new(CsvFormat::default()),
+            dir: dir_a.path(),
+            ext: "csv",
         },
     )
     .await?;
-    let csv_schema = DirSchema::create(
+    let schema_b = DirSchema::create(
         &state,
         DirSchemaOpts {
             format: Arc::new(CsvFormat::default()),
-            dir: &repo_dir.join("testing").join("data").join("csv"),
+            dir: dir_b.path(),
             ext: "csv",
         },
     )
     .await?;
+
     // register schemas into catalog
-    catalog.register_schema("parquet", parquet_schema.clone())?;
-    catalog.register_schema("csv", csv_schema.clone())?;
+    catalog.register_schema("schema_a", schema_a.clone())?;
+    catalog.register_schema("schema_b", schema_b.clone())?;
+
     // register our catalog in the context
     ctx.register_catalog("dircat", Arc::new(catalog));
     {
         // catalog was passed down into our custom catalog list since we overide the ctx's default
         let catalogs = catlist.catalogs.read().unwrap();
         assert!(catalogs.contains_key("dircat"));
     };
-    // take the first 5 (arbitrary amount) keys from our schema's hashmap.
+
+    // take the first 3 (arbitrary amount) keys from our schema's hashmap.
     // in our `DirSchema`, the table names are equivalent to their key in the hashmap,
     // so any key in the hashmap will now  be a queryable in our datafusion context.
-    let parquet_tables = {
-        let tables = parquet_schema.tables.read().unwrap();
-        tables.keys().take(5).cloned().collect::<Vec<_>>()
+    let tables = {
+        let tables = schema_a.tables.read().unwrap();
+        tables.keys().take(3).cloned().collect::<Vec<_>>()
     };
-    for table in parquet_tables {
-        println!("querying table {table} from parquet schema");
+    for table in tables {
+        log::info!("querying table {table} from schema_a");
         let df = ctx
-            .sql(&format!("select * from dircat.parquet.\"{table}\" "))
+            .sql(&format!("select * from dircat.schema_a.\"{table}\" "))
             .await?
             .limit(0, Some(5))?;
         let result = df.collect().await;
         match result {
             Ok(batches) => {
+                log::info!("query completed");
                 pretty::print_batches(&batches).unwrap();
             }
             Err(e) => {
-                println!("table '{table}' query failed due to {e}");
+                log::error!("table '{table}' query failed due to {e}");
             }
         }
     }
+
+    // Select table to drop from registered tables
     let table_to_drop = {
-        let parquet_tables = parquet_schema.tables.read().unwrap();
-        parquet_tables.keys().next().unwrap().to_owned()
+        let tables = schema_a.tables.read().unwrap();
+        tables.keys().next().unwrap().to_owned()
     };
-    // DDL example
-    let df = ctx
-        .sql(&format!("DROP TABLE dircat.parquet.\"{table_to_drop}\""))
+
+    // Execute drop table
+    let df: datafusion::prelude::DataFrame = ctx
+        .sql(&format!("DROP TABLE dircat.schema_a.\"{table_to_drop}\""))
         .await?;
     df.collect().await?;
-    let parquet_tables = parquet_schema.tables.read().unwrap();
-    // datafusion has deregistered the table from our schema
+
+    // Ensure that datafusion has deregistered the table from our schema
     // (called our schema's deregister func)
-    assert!(!parquet_tables.contains_key(&table_to_drop));
+    let tables = schema_a.tables.read().unwrap();
+    assert!(!tables.contains_key(&table_to_drop));
     Ok(())
 }
 
@@ -154,8 +159,14 @@ impl DirSchema {
             let conf = ListingTableConfig::new(table_path)
                 .with_listing_options(opts)
                 .infer_schema(state)
-                .await?;
-            let table = ListingTable::try_new(conf)?;
+                .await;
+
+            if let Err(err) = conf {
+                log::error!("Error while inferring schema for {filename}: {err}");
+                continue;
+            }
+
+            let table = ListingTable::try_new(conf?)?;
             tables.insert(filename, Arc::new(table) as Arc<dyn TableProvider>);
         }
         Ok(Arc::new(Self {
@@ -195,7 +206,7 @@ impl SchemaProvider for DirSchema {
         table: Arc<dyn TableProvider>,
     ) -> Result<Option<Arc<dyn TableProvider>>> {
         let mut tables = self.tables.write().unwrap();
-        println!("adding table {name}");
+        log::info!("adding table {name}");
         tables.insert(name, table.clone());
         Ok(Some(table))
     }
@@ -205,7 +216,7 @@ impl SchemaProvider for DirSchema {
     #[allow(unused_variables)]
     fn deregister_table(&self, name: &str) -> Result<Option<Arc<dyn TableProvider>>> {
         let mut tables = self.tables.write().unwrap();
-        println!("dropping table {name}");
+        log::info!("dropping table {name}");
         Ok(tables.remove(name))
     }
 }
@@ -287,3 +298,20 @@ impl CatalogProviderList for CustomCatalogProviderList {
         cats.get(name).cloned()
     }
 }
+
+fn prepare_example_data() -> Result<TempDir> {
+    let dir = tempfile::tempdir()?;
+    let path = dir.path();
+
+    let content = r#"key,value
+1,foo
+2,bar
+3,baz"#;
+
+    for i in 0..5 {
+        let mut file = File::create(path.join(format!("{}.csv", i)))?;
+        file.write_all(content.as_bytes())?;
+    }
+
+    Ok(dir)
+}