[function] SELECT VERSION()

Signed-off-by: Chojan Shang <psiace@outlook.com>

common/functions/src/udfs/mod.rs

@@ -13,8 +13,10 @@ mod database;
 mod to_type_name;
 mod udf;
 mod udf_example;
+mod version;
 
 pub use database::DatabaseFunction;
 pub use to_type_name::ToTypeNameFunction;
 pub use udf::UdfFunction;
 pub use udf_example::UdfExampleFunction;
+pub use version::VersionFunction;

common/functions/src/udfs/udf.rs

@@ -7,6 +7,7 @@ use common_exception::Result;
 use crate::udfs::DatabaseFunction;
 use crate::udfs::ToTypeNameFunction;
 use crate::udfs::UdfExampleFunction;
+use crate::udfs::VersionFunction;
 use crate::FactoryFuncRef;
 
 #[derive(Clone)]
@@ -18,6 +19,7 @@ impl UdfFunction {
         map.insert("example", UdfExampleFunction::try_create);
         map.insert("totypename", ToTypeNameFunction::try_create);
         map.insert("database", DatabaseFunction::try_create);
+        map.insert("version", VersionFunction::try_create);
         Ok(())
     }
 }

common/functions/src/udfs/version.rs

@@ -0,0 +1,53 @@
+// Copyright 2020-2021 The Datafuse Authors.
+//
+// SPDX-License-Identifier: Apache-2.0.
+
+use std::fmt;
+
+use common_datavalues::DataColumnarValue;
+use common_datavalues::DataSchema;
+use common_datavalues::DataType;
+use common_exception::Result;
+
+use crate::IFunction;
+
+#[derive(Clone)]
+pub struct VersionFunction {
+    display_name: String,
+}
+
+impl VersionFunction {
+    pub fn try_create(display_name: &str) -> Result<Box<dyn IFunction>> {
+        Ok(Box::new(VersionFunction {
+            display_name: display_name.to_string(),
+        }))
+    }
+}
+
+impl IFunction for VersionFunction {
+    fn name(&self) -> &str {
+        "VersionFunction"
+    }
+
+    fn return_type(&self, _args: &[DataType]) -> Result<DataType> {
+        Ok(DataType::Utf8)
+    }
+
+    fn nullable(&self, _input_schema: &DataSchema) -> Result<bool> {
+        Ok(false)
+    }
+
+    fn eval(&self, columns: &[DataColumnarValue], _input_rows: usize) -> Result<DataColumnarValue> {
+        Ok(columns[0].clone())
+    }
+
+    fn num_arguments(&self) -> usize {
+        1
+    }
+}
+
+impl fmt::Display for VersionFunction {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "version")
+    }
+}

fusequery/query/src/functions/context_function.rs

@@ -29,6 +29,9 @@ impl ContextFunction {
             "database" => vec![Expression::Literal(DataValue::Utf8(Some(
                 ctx.get_current_database(),
             )))],
+            "version" => vec![Expression::Literal(DataValue::Utf8(Some(
+                ctx.get_fuse_version(),
+            )))],
             _ => vec![],
         })
     }

fusequery/query/src/sessions/context.rs

@@ -39,6 +39,7 @@ pub struct FuseQueryContext {
     current_database: Arc<RwLock<String>>,
     progress: Arc<Progress>,
     runtime: Arc<RwLock<Runtime>>,
+    version: String,
 }
 
 pub type FuseQueryContextRef = Arc<FuseQueryContext>;
@@ -57,6 +58,10 @@ impl FuseQueryContext {
             current_database: Arc::new(RwLock::new(String::from("default"))),
             progress: Arc::new(Progress::create()),
             runtime: Arc::new(RwLock::new(Runtime::with_worker_threads(cpus)?)),
+            version: format!(
+                "FuseQuery v-{}",
+                crate::configs::config::FUSE_COMMIT_VERSION
+            ),
         };
         // Default settings.
         ctx.initial_settings()?;
@@ -218,6 +223,10 @@ impl FuseQueryContext {
         self.settings.try_update_u64("max_threads", threads)
     }
 
+    pub fn get_fuse_version(&self) -> String {
+        self.version.clone()
+    }
+
     apply_macros! { apply_getter_setter_settings, apply_initial_settings, apply_update_settings,
         ("max_block_size", u64, 10000, "Maximum block size for reading".to_string()),
         ("flight_client_timeout", u64, 60, "Max duration the flight client request is allowed to take in seconds. By default, it is 60 seconds".to_string()),