Accept template contents as strings instead of reading from disk (#161)

Makes use of the new upstream Template.New() to stop passing user-defined templates to the Grafana Alertmanager by persisting them to disk.

Author: JacobsonMT

notify/grafana_alertmanager.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"net/url"
-	"path/filepath"
 	"sync"
 	"time"
 
@@ -96,10 +95,9 @@ type GrafanaAlertmanager struct {
 	// buildReceiverIntegrationsFunc builds the integrations for a receiver based on its APIReceiver configuration and the current parsed template.
 	buildReceiverIntegrationsFunc func(next *APIReceiver, tmpl *templates.Template) ([]*Integration, error)
 	externalURL                   string
-	workingDirectory              string
 
-	// templates contains the filenames (not full paths) of the persisted templates that were used to construct the current parsed template.
-	templates []string
+	// templates contains the template name -> template contents for each user-defined template.
+	templates []templates.TemplateDefinition
 }
 
 // State represents any of the two 'states' of the alertmanager. Notification log or Silences.
@@ -145,14 +143,13 @@ type Configuration interface {
 	BuildReceiverIntegrationsFunc() func(next *APIReceiver, tmpl *templates.Template) ([]*Integration, error)
 
 	RoutingTree() *Route
-	Templates() []string
+	Templates() []templates.TemplateDefinition
 
 	Hash() [16]byte
 	Raw() []byte
 }
 
 type GrafanaAlertmanagerConfig struct {
-	WorkingDirectory   string
 	ExternalURL        string
 	AlertStoreCallback mem.AlertStoreCallback
 	PeerTimeout        time.Duration
@@ -187,7 +184,6 @@ func NewGrafanaAlertmanager(tenantKey string, tenantID int64, config *GrafanaAle
 		Metrics:           m,
 		tenantID:          tenantID,
 		externalURL:       config.ExternalURL,
-		workingDirectory:  config.WorkingDirectory,
 	}
 
 	if err := config.Validate(); err != nil {
@@ -302,10 +298,6 @@ func (am *GrafanaAlertmanager) ExternalURL() string {
 	return am.externalURL
 }
 
-func (am *GrafanaAlertmanager) WorkingDirectory() string {
-	return am.workingDirectory
-}
-
 // ConfigHash returns the hash of the current running configuration.
 // It is not safe to call without a lock.
 func (am *GrafanaAlertmanager) ConfigHash() [16]byte {
@@ -324,9 +316,9 @@ func (am *GrafanaAlertmanager) WithLock(fn func()) {
 	fn()
 }
 
-// TemplateFromPaths returns a set of *Templates based on the paths given.
-func (am *GrafanaAlertmanager) TemplateFromPaths(paths []string, options ...template.Option) (*templates.Template, error) {
-	tmpl, err := templates.FromGlobs(paths, options...)
+// TemplateFromContent returns a *Template based on defaults and the provided template contents.
+func (am *GrafanaAlertmanager) TemplateFromContent(tmpls []string, options ...template.Option) (*templates.Template, error) {
+	tmpl, err := templates.FromContent(tmpls, options...)
 	if err != nil {
 		return nil, err
 	}
@@ -354,13 +346,18 @@ func (am *GrafanaAlertmanager) buildTimeIntervals(timeIntervals []config.TimeInt
 func (am *GrafanaAlertmanager) ApplyConfig(cfg Configuration) (err error) {
 	am.templates = cfg.Templates()
 
-	// Create the parsed template using the template paths.
-	paths := make([]string, 0)
-	for _, name := range am.templates {
-		paths = append(paths, filepath.Join(am.workingDirectory, name))
+	seen := make(map[string]struct{})
+	tmpls := make([]string, 0, len(am.templates))
+	for _, tc := range am.templates {
+		if _, ok := seen[tc.Name]; ok {
+			level.Warn(am.logger).Log("msg", "template with same name is defined multiple times, skipping...", "template_name", tc.Name)
+			continue
+		}
+		tmpls = append(tmpls, tc.Template)
+		seen[tc.Name] = struct{}{}
 	}
 
-	tmpl, err := am.TemplateFromPaths(paths)
+	tmpl, err := am.TemplateFromContent(tmpls)
 	if err != nil {
 		return err
 	}

notify/templates.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"context"
 	tmplhtml "html/template"
-	"path/filepath"
 	tmpltext "text/template"
 
 	"github.com/grafana/alerting/templates"
@@ -74,30 +73,31 @@ func (am *GrafanaAlertmanager) TestTemplate(ctx context.Context, c TestTemplates
 		}, nil
 	}
 
-	// Recreate the current template without the definition blocks that are being tested. This is so that any blocks that were removed don't get defined.
-	paths := make([]string, 0)
-	for _, name := range am.templates {
-		if name == c.Name {
-			// Skip the existing template of the same name as we're going to parse the one for testing instead.
+	// Recreate the current template replacing the definition blocks that are being tested. This is so that any blocks that were removed don't get defined.
+	var found bool
+	templateContents := make([]string, 0, len(am.templates)+1)
+	for _, td := range am.templates {
+		if td.Name == c.Name {
+			// Template already exists, test with the new definition replacing the old one.
+			templateContents = append(templateContents, c.Template)
+			found = true
 			continue
 		}
-		paths = append(paths, filepath.Join(am.workingDirectory, name))
+		templateContents = append(templateContents, td.Template)
 	}
 
-	// Parse current templates.
+	if !found {
+		// Template is a new one, add it to the list.
+		templateContents = append(templateContents, c.Template)
+	}
+
+	// Capture the underlying text template so we can use ExecuteTemplate.
 	var newTextTmpl *tmpltext.Template
 	var captureTemplate template.Option = func(text *tmpltext.Template, _ *tmplhtml.Template) {
 		newTextTmpl = text
 	}
-	newTmpl, err := am.TemplateFromPaths(paths, captureTemplate)
-	if err != nil {
-		return nil, err
-	}
-
-	// Parse test template.
-	_, err = newTextTmpl.New(c.Name).Parse(c.Template)
+	newTmpl, err := am.TemplateFromContent(templateContents, captureTemplate)
 	if err != nil {
-		// This shouldn't happen since we already parsed the template above.
 		return nil, err
 	}
 

notify/templates_test.go

@@ -3,11 +3,11 @@ package notify
 import (
 	"context"
 	"errors"
-	"os"
-	"path/filepath"
 	"testing"
 	"text/template"
 
+	"github.com/grafana/alerting/templates"
+
 	"github.com/go-openapi/strfmt"
 	amv2 "github.com/prometheus/alertmanager/api/v2/models"
 	"github.com/stretchr/testify/assert"
@@ -102,7 +102,7 @@ func TestTemplateSimple(t *testing.T) {
 				Kind: ExecutionError,
 				Error: template.ExecError{
 					Name: "slack.title",
-					Err:  errors.New(`template: slack.title:1:38: executing "slack.title" at <{{template "missing" .}}>: template "missing" not defined`),
+					Err:  errors.New(`template: :1:38: executing "slack.title" at <{{template "missing" .}}>: template "missing" not defined`),
 				},
 			}},
 		},
@@ -154,7 +154,7 @@ func TestTemplateSimple(t *testing.T) {
 				Kind: ExecutionError,
 				Error: template.ExecError{
 					Name: "other",
-					Err:  errors.New(`template: slack.title:1:91: executing "other" at <{{template "missing" .}}>: template "missing" not defined`),
+					Err:  errors.New(`template: :1:91: executing "other" at <{{template "missing" .}}>: template "missing" not defined`),
 				},
 			}},
 		},
@@ -275,17 +275,10 @@ func TestTemplateSpecialCases(t *testing.T) {
 
 func TestTemplateWithExistingTemplates(t *testing.T) {
 	am, _ := setupAMTest(t)
-	tmpDir, err := os.MkdirTemp("", "test-templates")
-	require.NoError(t, err)
-	t.Cleanup(func() {
-		require.NoError(t, os.RemoveAll(tmpDir))
-	})
-
-	am.workingDirectory = tmpDir
 
 	tests := []struct {
 		name              string
-		existingTemplates map[string]string
+		existingTemplates []templates.TemplateDefinition
 		input             TestTemplatesConfigBodyParams
 		expected          TestTemplatesResults
 	}{{
@@ -310,9 +303,10 @@ func TestTemplateWithExistingTemplates(t *testing.T) {
 			Name:     "slack.title",
 			Template: `{{ define "slack.title" }}{{ template "existing" . }}{{ end }}`,
 		},
-		existingTemplates: map[string]string{
-			"existing": `{{ define "existing" }}Some existing template{{ end }}`,
-		},
+		existingTemplates: []templates.TemplateDefinition{{
+			Name:     "existing",
+			Template: `{{ define "existing" }}Some existing template{{ end }}`,
+		}},
 		expected: TestTemplatesResults{
 			Results: []TestTemplatesResult{{
 				Name: "slack.title",
@@ -327,9 +321,10 @@ func TestTemplateWithExistingTemplates(t *testing.T) {
 			Name:     "slack.title",
 			Template: `{{ define "slack.title" }}New template{{ end }}`,
 		},
-		existingTemplates: map[string]string{
-			"slack.title": `{{ define "slack.title" }}Some existing template{{ end }}`,
-		},
+		existingTemplates: []templates.TemplateDefinition{{
+			Name:     "slack.title",
+			Template: `{{ define "slack.title" }}Some existing template{{ end }}`,
+		}},
 		expected: TestTemplatesResults{
 			Results: []TestTemplatesResult{{
 				Name: "slack.title",
@@ -344,17 +339,18 @@ func TestTemplateWithExistingTemplates(t *testing.T) {
 			Name:     "slack.title",
 			Template: `{{ define "slack.title" }}{{ template "slack.alternate_title" . }}{{ end }}`,
 		},
-		existingTemplates: map[string]string{
-			"slack.title": `{{ define "slack.title" }}Some existing template{{ end }}{{ define "slack.alternate_title" }}Some existing alternate template{{ end }}`,
-		},
+		existingTemplates: []templates.TemplateDefinition{{
+			Name:     "slack.title",
+			Template: `{{ define "slack.title" }}Some existing template{{ end }}{{ define "slack.alternate_title" }}Some existing alternate template{{ end }}`,
+		}},
 		expected: TestTemplatesResults{
 			Results: nil,
 			Errors: []TestTemplatesErrorResult{{
 				Name: "slack.title",
 				Kind: ExecutionError,
 				Error: template.ExecError{
 					Name: "slack.title",
-					Err:  errors.New(`template: slack.title:1:38: executing "slack.title" at <{{template "slack.alternate_title" .}}>: template "slack.alternate_title" not defined`),
+					Err:  errors.New(`template: :1:38: executing "slack.title" at <{{template "slack.alternate_title" .}}>: template "slack.alternate_title" not defined`),
 				},
 			}},
 		},
@@ -365,9 +361,10 @@ func TestTemplateWithExistingTemplates(t *testing.T) {
 			Name:     "slack.title",
 			Template: `{{ define "slack.title" }}{{ template "slack.alternate_title" . }}{{ end }}{{ define "slack.alternate_title" }}Some new alternate template{{ end }}`,
 		},
-		existingTemplates: map[string]string{
-			"slack.title": `{{ define "slack.title" }}Some existing template{{ end }}{{ define "slack.alternate_title" }}Some existing alternate template{{ end }}`,
-		},
+		existingTemplates: []templates.TemplateDefinition{{
+			Name:     "slack.title",
+			Template: `{{ define "slack.title" }}Some existing template{{ end }}{{ define "slack.alternate_title" }}Some existing alternate template{{ end }}`,
+		}},
 		expected: TestTemplatesResults{
 			Results: []TestTemplatesResult{{
 				Name: "slack.title",
@@ -381,10 +378,7 @@ func TestTemplateWithExistingTemplates(t *testing.T) {
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
 			if len(test.existingTemplates) > 0 {
-				for name, tmpl := range test.existingTemplates {
-					createTemplate(t, tmpDir, name, tmpl)
-					am.templates = append(am.templates, name)
-				}
+				am.templates = test.existingTemplates
 			}
 			res, err := am.TestTemplate(context.Background(), test.input)
 			require.NoError(t, err)
@@ -436,18 +430,3 @@ CommonAnnotations: {{ range .CommonAnnotations.SortedPairs }}{{ .Name }}={{ .Val
 		})
 	}
 }
-
-func createTemplate(t *testing.T, tmpDir string, name string, tmpl string) {
-	f, err := os.Create(filepath.Join(tmpDir, name))
-	require.NoError(t, err)
-	defer func(f *os.File) {
-		_ = f.Close()
-	}(f)
-
-	t.Cleanup(func() {
-		require.NoError(t, os.RemoveAll(f.Name()))
-	})
-
-	_, err = f.WriteString(tmpl)
-	require.NoError(t, err)
-}

templates/default_template.go

@@ -1,10 +1,8 @@
 package templates
 
 import (
-	"os"
 	"testing"
 
-	"github.com/prometheus/alertmanager/template"
 	"github.com/stretchr/testify/require"
 )
 
@@ -102,21 +100,7 @@ Labels:
 `
 
 func ForTests(t *testing.T) *Template {
-	f, err := os.CreateTemp("/tmp", "template")
+	tmpl, err := FromContent([]string{TemplateForTestsString})
 	require.NoError(t, err)
-	defer func(f *os.File) {
-		_ = f.Close()
-	}(f)
-
-	t.Cleanup(func() {
-		require.NoError(t, os.RemoveAll(f.Name()))
-	})
-
-	_, err = f.WriteString(TemplateForTestsString)
-	require.NoError(t, err)
-
-	tmpl, err := template.FromGlobs([]string{f.Name()})
-	require.NoError(t, err)
-
 	return tmpl
 }

templates/default_template_test.go

@@ -3,7 +3,6 @@ package templates
 import (
 	"context"
 	"net/url"
-	"os"
 	"testing"
 	"time"
 
@@ -117,20 +116,7 @@ func TestDefaultTemplateString(t *testing.T) {
 		},
 	}
 
-	f, err := os.CreateTemp("/tmp", "template")
-	require.NoError(t, err)
-	defer func(f *os.File) {
-		_ = f.Close()
-	}(f)
-
-	t.Cleanup(func() {
-		require.NoError(t, os.RemoveAll(f.Name()))
-	})
-
-	_, err = f.WriteString(DefaultTemplateString)
-	require.NoError(t, err)
-
-	tmpl, err := FromGlobs([]string{f.Name()})
+	tmpl, err := FromContent(nil)
 	require.NoError(t, err)
 
 	externalURL, err := url.Parse("http://localhost/grafana")