add support for library

internal/testdata/init/templateDefinition/library/foo

@@ -0,0 +1,6 @@
+{{define "email"}}shreyas.goenka@databricks.com{{end}}
+{{define "get_host"}}
+{{ with urlParse . }}{{-
+    print .Scheme `://` .Host
+-}}{{end}}
+{{end}}

internal/testdata/init/templateDefinition/template/{{.project_name}}/azure_file

@@ -2,3 +2,6 @@ This file should only be generated for Azure
 {{if ne .cloud_type "Azure"}}
 {{skipThisFile}}
 {{end}}
+
+{{ template "email" }}
+{{ template "get_host" "https://adb-xxxx.xx.azuredatabricks.net/sql/queries" }}

libs/template/execute.go

@@ -2,6 +2,7 @@ package template
 
 import (
 	"errors"
+	"fmt"
 	"io/fs"
 	"os"
 	"path/filepath"
@@ -9,39 +10,63 @@ import (
 	"text/template"
 )
 
-// Executes the template by applying config on it. Returns the materialized config
+type renderer struct {
+	config map[string]any
+
+	baseTemplate *template.Template
+}
+
+func newRenderer(config map[string]any, libraryRoot string) (*renderer, error) {
+	tmpl, err := template.New("").Funcs(HelperFuncs).ParseGlob(filepath.Join(libraryRoot, "*"))
+	if err != nil {
+		return nil, err
+	}
+
+	return &renderer{
+		config:       config,
+		baseTemplate: tmpl,
+	}, nil
+}
+
+// Executes the template by applying config on it. Returns the materialized template
 // as a string
-func executeTemplate(config map[string]any, templateDefinition string) (string, error) {
-	// configure template with helper functions
-	tmpl, err := template.New("").Funcs(HelperFuncs).Parse(templateDefinition)
+func (r *renderer) executeTemplate(templateDefinition string) (string, error) {
+	// Create copy of base template so as to not overwrite it
+	tmpl, err := r.baseTemplate.Clone()
 	if err != nil {
 		return "", err
 	}
 
-	// execute template
+	// Parse the template text
+	tmpl, err = tmpl.Parse(templateDefinition)
+	if err != nil {
+		return "", err
+	}
+
+	// Execute template and get result
 	result := strings.Builder{}
-	err = tmpl.Execute(&result, config)
+	err = tmpl.Execute(&result, r.config)
 	if err != nil {
 		return "", err
 	}
 	return result.String(), nil
 }
 
-func generateFile(config map[string]any, pathTemplate, contentTemplate string, perm fs.FileMode) error {
+func (r *renderer) generateFile(pathTemplate, contentTemplate string, perm fs.FileMode) error {
 	// compute file content
-	fileContent, err := executeTemplate(config, contentTemplate)
+	fileContent, err := r.executeTemplate(contentTemplate)
 	if errors.Is(err, errSkipThisFile) {
 		// skip this file
 		return nil
 	}
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to compute file content for %s. %w", pathTemplate, err)
 	}
 
 	// compute the path for this file
-	path, err := executeTemplate(config, pathTemplate)
+	path, err := r.executeTemplate(pathTemplate)
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to compute path for %s. %w", pathTemplate, err)
 	}
 	// create any intermediate directories required. Directories are lazily generated
 	// only when they are required for a file.
@@ -55,7 +80,7 @@ func generateFile(config map[string]any, pathTemplate, contentTemplate string, p
 }
 
 // TODO: use local filer client for this function. https://github.com/databricks/cli/issues/511
-func walkFileTree(config map[string]any, templateRoot, instanceRoot string) error {
+func walkFileTree(r *renderer, templateRoot, instanceRoot string) error {
 	return filepath.WalkDir(templateRoot, func(path string, d fs.DirEntry, err error) error {
 		if err != nil {
 			return err
@@ -87,6 +112,6 @@ func walkFileTree(config map[string]any, templateRoot, instanceRoot string) erro
 			return err
 		}
 
-		return generateFile(config, filepath.Join(instanceRoot, relPathTemplate), contentTemplate, info.Mode().Perm())
+		return r.generateFile(filepath.Join(instanceRoot, relPathTemplate), contentTemplate, info.Mode().Perm())
 	})
 }

libs/template/execute_test.go

@@ -4,6 +4,7 @@ import (
 	"os"
 	"path/filepath"
 	"testing"
+	"text/template"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -17,22 +18,40 @@ Sheep wool is the best!
 {{else}}
 {{.Animal}} wool is not too bad...
 {{end}}
+My email is {{template "email"}}
 `
-	statement, err := executeTemplate(map[string]any{
-		"Material": "wool",
-		"count":    1,
-		"Animal":   "sheep",
-	}, templateText)
-	require.NoError(t, err)
-	assert.Equal(t, "\"1 items are made of wool\".\n\nSheep wool is the best!\n\n", statement)
 
-	statement, err = executeTemplate(map[string]any{
-		"Material": "wool",
-		"count":    1,
-		"Animal":   "cat",
-	}, templateText)
+	r := renderer{
+		config: map[string]any{
+			"Material": "wool",
+			"count":    1,
+			"Animal":   "sheep",
+		},
+		baseTemplate: template.Must(template.New("base").Parse(`{{define "email"}}shreyas.goenka@databricks.com{{end}}`)),
+	}
+
+	statement, err := r.executeTemplate(templateText)
 	require.NoError(t, err)
-	assert.Equal(t, "\"1 items are made of wool\".\n\ncat wool is not too bad...\n\n", statement)
+	assert.Contains(t, statement, `"1 items are made of wool"`)
+	assert.NotContains(t, statement, `cat wool is not too bad.."`)
+	assert.Contains(t, statement, "Sheep wool is the best!")
+	assert.Contains(t, statement, `My email is shreyas.goenka@databricks.com`)
+
+	r = renderer{
+		config: map[string]any{
+			"Material": "wool",
+			"count":    1,
+			"Animal":   "cat",
+		},
+		baseTemplate: template.Must(template.New("base").Parse(`{{define "email"}}hrithik.roshan@databricks.com{{end}}`)),
+	}
+
+	statement, err = r.executeTemplate(templateText)
+	require.NoError(t, err)
+	assert.Contains(t, statement, `"1 items are made of wool"`)
+	assert.Contains(t, statement, `cat wool is not too bad...`)
+	assert.NotContains(t, statement, "Sheep wool is the best!")
+	assert.Contains(t, statement, `My email is hrithik.roshan@databricks.com`)
 }
 
 func TestGenerateFile(t *testing.T) {
@@ -46,11 +65,16 @@ func TestGenerateFile(t *testing.T) {
 	{{.Animal}} wool is not too bad...
 	{{end}}
 	`
-	err := generateFile(map[string]any{
-		"Material": "wool",
-		"count":    1,
-		"Animal":   "cat",
-	}, pathTemplate, contentTemplate, 0444)
+
+	r := renderer{
+		config: map[string]any{
+			"Material": "wool",
+			"count":    1,
+			"Animal":   "cat",
+		},
+		baseTemplate: template.New("base"),
+	}
+	err := r.generateFile(pathTemplate, contentTemplate, 0444)
 	require.NoError(t, err)
 
 	// assert file exists

libs/template/helpers.go

@@ -2,6 +2,7 @@ package template
 
 import (
 	"errors"
+	"net/url"
 	"text/template"
 )
 
@@ -13,4 +14,7 @@ var HelperFuncs = template.FuncMap{
 	"skipThisFile": func() (any, error) {
 		return nil, errSkipThisFile
 	},
+	"urlParse": func(rawUrl string) (*url.URL, error) {
+		return url.Parse(rawUrl)
+	},
 }

libs/template/materialize.go

@@ -6,6 +6,7 @@ import (
 
 const schemaFileName = "databricks_template_schema.json"
 const templateDirName = "template"
+const libraryDirName = "library"
 
 func Materialize(templateRoot, instanceRoot, configPath string) error {
 	// read the file containing schema for template input parameters
@@ -14,12 +15,17 @@ func Materialize(templateRoot, instanceRoot, configPath string) error {
 		return err
 	}
 
-	// read user config to initalize the template with
+	// read user config to initialize the template with
 	config, err := schema.ReadConfig(configPath)
 	if err != nil {
 		return err
 	}
 
+	r, err := newRenderer(config, filepath.Join(templateRoot, libraryDirName))
+	if err != nil {
+		return err
+	}
+
 	// materialize the template
-	return walkFileTree(config, filepath.Join(templateRoot, templateDirName), instanceRoot)
+	return walkFileTree(r, filepath.Join(templateRoot, templateDirName), instanceRoot)
 }