fix(tsdb): survive low disk space

service/singleton/tsdb_disk_guard_test.go

@@ -0,0 +1,58 @@
+package singleton
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/nezhahq/nezha/model"
+	"github.com/nezhahq/nezha/pkg/tsdb"
+)
+
+func TestInitTSDBContinuesWhenDiskIsFull(t *testing.T) {
+	originalConf := Conf
+	originalDB := DB
+	originalShared := TSDBShared
+	originalOpen := openTSDB
+	t.Cleanup(func() {
+		Conf = originalConf
+		DB = originalDB
+		TSDBShared = originalShared
+		openTSDB = originalOpen
+	})
+
+	Conf = &ConfigClass{Config: &model.Config{
+		TSDB: model.TSDBConf{DataPath: "/full/tsdb"},
+	}}
+	DB = nil
+	TSDBShared = nil
+	openTSDB = func(*tsdb.Config) (*tsdb.TSDB, error) {
+		return nil, fmt.Errorf("open failed: %w", tsdb.ErrDiskFull)
+	}
+
+	require.NoError(t, InitTSDB())
+	require.Nil(t, TSDBShared)
+}
+
+func TestInitTSDBStillReturnsNonDiskErrors(t *testing.T) {
+	originalConf := Conf
+	originalShared := TSDBShared
+	originalOpen := openTSDB
+	t.Cleanup(func() {
+		Conf = originalConf
+		TSDBShared = originalShared
+		openTSDB = originalOpen
+	})
+
+	Conf = &ConfigClass{Config: &model.Config{
+		TSDB: model.TSDBConf{DataPath: "/broken/tsdb"},
+	}}
+	TSDBShared = nil
+	openTSDB = func(*tsdb.Config) (*tsdb.TSDB, error) {
+		return nil, fmt.Errorf("permission denied")
+	}
+
+	require.ErrorContains(t, InitTSDB(), "permission denied")
+	require.Nil(t, TSDBShared)
+}