Add panic recovery (#173)

* panic recovery added

* Update datasource.go

Refactor error source in the response

Co-authored-by: Nathan Vērzemnieks <[email protected]>

* - remove query from the error response

---------

Co-authored-by: Nathan Vērzemnieks <[email protected]>

Author: sasklacz

datasource.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"net/http"
 	"os"
+	"runtime/debug"
 	"strconv"
 	"sync"
 	"time"
@@ -119,6 +120,23 @@ func (ds *SQLDatasource) QueryData(ctx context.Context, req *backend.QueryDataRe
 	// Execute each query and store the results by query RefID
 	for _, q := range req.Queries {
 		go func(query backend.DataQuery) {
+			defer wg.Done()
+
+			// Panic recovery
+			defer func() {
+				if r := recover(); r != nil {
+					stack := string(debug.Stack())
+					errorMsg := fmt.Sprintf("SQL datasource query execution panic: %v", r)
+
+					backend.Logger.Error(errorMsg,
+						"panic", r,
+						"refID", query.RefID,
+						"stack", stack)
+
+					response.Set(query.RefID, backend.ErrorResponseWithErrorSource(backend.PluginError(errors.New(errorMsg))))
+				}
+			}()
+
 			frames, err := ds.handleQuery(ctx, query, headers)
 			if err == nil {
 				if responseMutator, ok := ds.driver().(ResponseMutator); ok {
@@ -134,8 +152,6 @@ func (ds *SQLDatasource) QueryData(ctx context.Context, req *backend.QueryDataRe
 				Error:       err,
 				ErrorSource: ErrorSource(err),
 			})
-
-			wg.Done()
 		}(q)
 	}
 

datasource_test.go

@@ -191,6 +191,38 @@ func Test_default_macro_errors(t *testing.T) {
 	}
 }
 
+func Test_query_panic_recovery(t *testing.T) {
+	cfg := `{ "timeout": 0, "retries": 0, "retryOn": [] }`
+	opts := test.DriverOpts{}
+
+	// Create a macro that triggers a panic
+	panicMacro := func(query *sqlds.Query, args []string) (string, error) {
+		panic("Random panic for testing purposes")
+	}
+	macros := sqlds.Macros{
+		"panicTest": panicMacro,
+	}
+
+	req, _, ds := queryRequest(t, "panic-test", opts, cfg, macros)
+
+	// Set up a query that uses the panic-triggering macro
+	req.Queries[0].JSON = []byte(`{ "rawSql": "SELECT $__panicTest() FROM test_table;" }`)
+
+	// Execute the query
+	data, err := ds.QueryData(context.Background(), req)
+
+	// Verify that the panic was caught and converted to an error
+	assert.Nil(t, err)
+	assert.NotNil(t, data.Responses)
+
+	res := data.Responses["foo"]
+	assert.NotNil(t, res.Error)
+	assert.Equal(t, backend.ErrorSourcePlugin, res.ErrorSource)
+	assert.Contains(t, res.Error.Error(), "SQL datasource query execution panic")
+	assert.Contains(t, res.Error.Error(), "Random panic for testing purposes")
+	assert.Nil(t, res.Frames)
+}
+
 func queryRequest(t *testing.T, name string, opts test.DriverOpts, cfg string, marcos sqlds.Macros) (*backend.QueryDataRequest, *test.SqlHandler, *sqlds.SQLDatasource) {
 	driver, handler := test.NewDriver(name, test.Data{}, nil, opts, marcos)
 	ds := sqlds.NewDatasource(driver)