Revert "Alerting: add template funcs (#38404)" (#39258)

This reverts commit d6fb0181fb.

pkg/services/ngalert/state/cache_test.go

@@ -0,0 +1,126 @@
+package state
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/grafana/grafana-plugin-sdk-go/data"
+	"github.com/grafana/grafana/pkg/services/ngalert/eval"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	ptr "github.com/xorcare/pointer"
+)
+
+func TestTemplateCaptureValueStringer(t *testing.T) {
+	cases := []struct {
+		name     string
+		value    templateCaptureValue
+		expected string
+	}{{
+		name:     "0 is returned as integer value",
+		value:    templateCaptureValue{Value: 0},
+		expected: "0",
+	}, {
+		name:     "1.0 is returned as integer value",
+		value:    templateCaptureValue{Value: 1.0},
+		expected: "1",
+	}, {
+		name:     "1.1 is returned as decimal value",
+		value:    templateCaptureValue{Value: 1.1},
+		expected: "1.1",
+	}}
+
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			assert.Equal(t, c.expected, c.value.String())
+		})
+	}
+}
+
+func TestExpandTemplate(t *testing.T) {
+	cases := []struct {
+		name          string
+		text          string
+		alertInstance eval.Result
+		labels        data.Labels
+		expected      string
+		expectedError error
+	}{{
+		name:     "labels are expanded into $labels",
+		text:     "{{ $labels.instance }} is down",
+		labels:   data.Labels{"instance": "foo"},
+		expected: "foo is down",
+	}, {
+		name:          "missing label in $labels returns error",
+		text:          "{{ $labels.instance }} is down",
+		labels:        data.Labels{},
+		expectedError: errors.New("error executing template __alert_test: template: __alert_test:1:86: executing \"__alert_test\" at <$labels.instance>: map has no entry for key \"instance\""),
+	}, {
+		name: "values are expanded into $values",
+		text: "{{ $values.A.Labels.instance }} has value {{ $values.A }}",
+		alertInstance: eval.Result{
+			Values: map[string]eval.NumberValueCapture{
+				"A": {
+					Var:    "A",
+					Labels: data.Labels{"instance": "foo"},
+					Value:  ptr.Float64(1),
+				},
+			},
+		},
+		expected: "foo has value 1",
+	}, {
+		name: "values can be passed to template functions such as printf",
+		text: "{{ $values.A.Labels.instance }} has value {{ $values.A.Value | printf \"%.1f\" }}",
+		alertInstance: eval.Result{
+			Values: map[string]eval.NumberValueCapture{
+				"A": {
+					Var:    "A",
+					Labels: data.Labels{"instance": "foo"},
+					Value:  ptr.Float64(1.1),
+				},
+			},
+		},
+		expected: "foo has value 1.1",
+	}, {
+		name: "missing label in $values returns error",
+		text: "{{ $values.A.Labels.instance }} has value {{ $values.A }}",
+		alertInstance: eval.Result{
+			Values: map[string]eval.NumberValueCapture{
+				"A": {
+					Var:    "A",
+					Labels: data.Labels{},
+					Value:  ptr.Float64(1),
+				},
+			},
+		},
+		expectedError: errors.New("error executing template __alert_test: template: __alert_test:1:86: executing \"__alert_test\" at <$values.A.Labels.instance>: map has no entry for key \"instance\""),
+	}, {
+		name: "missing value in $values is returned as NaN",
+		text: "{{ $values.A.Labels.instance }} has value {{ $values.A }}",
+		alertInstance: eval.Result{
+			Values: map[string]eval.NumberValueCapture{
+				"A": {
+					Var:    "A",
+					Labels: data.Labels{"instance": "foo"},
+					Value:  nil,
+				},
+			},
+		},
+		expected: "foo has value NaN",
+	}, {
+		name: "assert value string is expanded into $value",
+		text: "{{ $value }}",
+		alertInstance: eval.Result{
+			EvaluationString: "[ var='A' labels={instance=foo} value=10 ]",
+		},
+		expected: "[ var='A' labels={instance=foo} value=10 ]",
+	}}
+
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			v, err := expandTemplate("test", c.text, c.labels, c.alertInstance)
+			require.Equal(t, c.expectedError, err)
+			require.Equal(t, c.expected, v)
+		})
+	}
+}