readyset-adapter: Add ALTER READYSET SET LOG LEVEL statement

This accepts a string argument, e.g.:

```
readyset> ALTER READYSET SET LOG LEVEL 'trace';
Query OK, 0 rows affected (0.00 sec)
```

Addresses: REA-4986
Release-Note-Core: You can now set the log level at runtime using the
  `ALTER READYSET SET LOG LEVEL` statement or the `/log_level` HTTP
  endpoint. For example: `ALTER READYSET SET LOG LEVEL
  'info,readyset_adapter=debug'`; or `curl -X POST -d
  'info,readyset_adapter=debug' http://readyset:6033/log_level`.

Change-Id: I6a6a6964c4609e41794d33dff7467d5db7585bda
Reviewed-on: https://gerrit.readyset.name/c/readyset/+/10083
Tested-by: Buildkite CI
Reviewed-by: Johnathan Davis <jcd@readyset.io>

Author: mvzink

readyset-adapter/src/backend.rs

@@ -2596,6 +2596,12 @@ where
             SqlQuery::AlterReadySet(AlterReadysetStatement::ExitMaintenanceMode) => {
                 self.noria.exit_maintenance_mode().await
             }
+            SqlQuery::AlterReadySet(AlterReadysetStatement::SetLogLevel(directives)) => {
+                match readyset_tracing::set_log_level(directives) {
+                    Ok(()) => Ok(noria_connector::QueryResult::Empty),
+                    Err(e) => Err(internal_err!("Failed to set log level: {e}")),
+                }
+            }
             SqlQuery::CreateRls(_create_rls) => {
                 unsupported!("CREATE RLS statement is not yet supported")
             }

readyset-sql-parsing/src/lib.rs

@@ -383,6 +383,11 @@ fn parse_alter(parser: &mut Parser, dialect: Dialect) -> Result<SqlQuery, Readys
             Ok(SqlQuery::AlterReadySet(
                 AlterReadysetStatement::ExitMaintenanceMode,
             ))
+        } else if parser.parse_keywords(&[Keyword::SET, Keyword::LOG, Keyword::LEVEL]) {
+            let directives = parser.parse_literal_string()?;
+            Ok(SqlQuery::AlterReadySet(
+                AlterReadysetStatement::SetLogLevel(directives),
+            ))
         } else {
             Err(ReadysetParsingError::ReadysetParsingError(
                 "expected RESNAPSHOT TABLE, or ADD TABLES after READYSET".into(),

readyset-sql/src/analysis/visit.rs

@@ -1098,8 +1098,9 @@ pub fn walk_alter_readyset_statement<'a, V: Visitor<'a>>(
             .tables
             .iter()
             .try_for_each(|table| visitor.visit_table(table)),
-        AlterReadysetStatement::EnterMaintenanceMode => Ok(()),
-        AlterReadysetStatement::ExitMaintenanceMode => Ok(()),
+        AlterReadysetStatement::EnterMaintenanceMode
+        | AlterReadysetStatement::ExitMaintenanceMode
+        | AlterReadysetStatement::SetLogLevel(_) => Ok(()),
     }
 }
 

readyset-sql/src/analysis/visit_mut.rs

@@ -1088,8 +1088,9 @@ pub fn walk_alter_readyset_statement<'a, V: VisitorMut<'a>>(
             .tables
             .iter_mut()
             .try_for_each(|table| visitor.visit_table(table)),
-        AlterReadysetStatement::EnterMaintenanceMode => Ok(()),
-        AlterReadysetStatement::ExitMaintenanceMode => Ok(()),
+        AlterReadysetStatement::EnterMaintenanceMode
+        | AlterReadysetStatement::ExitMaintenanceMode
+        | AlterReadysetStatement::SetLogLevel(_) => Ok(()),
     }
 }
 

readyset-sql/src/ast/alter.rs

@@ -415,6 +415,7 @@ pub enum AlterReadysetStatement {
     AddTables(AddTablesStatement),
     EnterMaintenanceMode,
     ExitMaintenanceMode,
+    SetLogLevel(String),
 }
 
 impl DialectDisplay for AlterReadysetStatement {
@@ -436,6 +437,9 @@ impl DialectDisplay for AlterReadysetStatement {
             Self::ExitMaintenanceMode => {
                 write!(f, "EXIT MAINTENANCE MODE")
             }
+            Self::SetLogLevel(level) => {
+                write!(f, "SET LOG LEVEL '{}'", level)
+            }
         })
     }
 }