5 files changed, 182 insertions(+), 2 deletions(-)

M cmd/govern/main.go
A example/template/bar/baz.tpl
A example/template/baz.tpl
A example/template/foo.tpl
A pkg/template/template.go

@@ 7,12 7,14 @@ import (
 	"sort"
 	"strings"
 	"text/tabwriter"
+	gotemplate "text/template"
 	"time"
 
 	"git.sr.ht/~nesv/govern/pkg/facts"
 	"git.sr.ht/~nesv/govern/pkg/resource"
 	"git.sr.ht/~nesv/govern/pkg/runner"
 	"git.sr.ht/~nesv/govern/pkg/state"
+	"git.sr.ht/~nesv/govern/pkg/template"
 
 	"github.com/nesv/cmndr"
 	"github.com/pkg/errors"


@@ 26,6 28,7 @@ var (
 	factsIgnore    []string
 	stateDirs      []string
 	statesIgnore   []string
+	templateDirs   []string
 	pretend        bool
 	withAttributes bool
 	runnerDirs     []string


@@ 47,6 50,10 @@ var (
 		"/usr/local/lib/govern/bin",
 		"/usr/lib/govern/bin",
 	}
+
+	defaultTemplateDirs = []string{
+		"/usr/local/etc/govern/templates.d",
+	}
 )
 
 func main() {


@@ 66,6 73,7 @@ func main() {
 	root.Flags.BoolVar(&withAttributes, "with-attributes", false, "Show resource attributes with --pretend, -n")
 	root.Flags.StringSliceVarP(&runnerDirs, "runners-directory", "R", defaultRunnerDirs, "Directories to look for runners in")
 	root.Flags.BoolVar(&withSignals, "with-signals", false, "resources: Show the signals a resource can send")
+	root.Flags.StringSliceVarP(&templateDirs, "template-directory", "T", defaultTemplateDirs, "Directories to look for templates")
 
 	facts := cmndr.New("facts", gatherFacts)
 	facts.Description = "Collect facts for the current host"


@@ 87,6 95,14 @@ func main() {
 	runners.Description = "List all discovered runners"
 	root.AddCmd(runners)
 
+	templates := cmndr.New("templates", showTemplates)
+	templates.Description = "List all discovered templates"
+	root.AddCmd(templates)
+
+	render := cmndr.New("render", renderTemplate)
+	render.Description = "Render a template"
+	root.AddCmd(render)
+
 	root.Exec()
 }
 


@@ 133,7 149,7 @@ func showStates(cmd *cmndr.Cmd, args []string) error {
 }
 
 func collectStates() (*state.States, error) {
-	for len(stateDirs) == 0 {
+	if len(stateDirs) == 0 {
 		stateDirs = make([]string, 0, len(defaultStateDirs))
 		copy(stateDirs, defaultStateDirs)
 	}


@@ 295,7 311,7 @@ func showRunners(cmd *cmndr.Cmd, args []string) error {
 }
 
 func collectRunners() (runner.Runners, error) {
-	for len(runnerDirs) == 0 {
+	if len(runnerDirs) == 0 {
 		runnerDirs = make([]string, 0, len(defaultRunnerDirs))
 		copy(runnerDirs, defaultRunnerDirs)
 	}


@@ 307,3 323,54 @@ func collectRunners() (runner.Runners, error) {
 
 	return runner.Gather(options...)
 }
+
+func showTemplates(cmd *cmndr.Cmd, args []string) error {
+	tpl, err := collectTemplates()
+	if err != nil {
+		return fmt.Errorf("collect templates: %w", err)
+	}
+	if tpl == nil {
+		return nil
+	}
+
+	for _, t := range tpl.Templates() {
+		fmt.Println(t.Name())
+	}
+	return nil
+}
+
+func collectTemplates() (*gotemplate.Template, error) {
+	if len(templateDirs) == 0 {
+		templateDirs = make([]string, 0, len(defaultTemplateDirs))
+		copy(templateDirs, defaultTemplateDirs)
+	}
+
+	ff, err := collectFacts()
+	if err != nil {
+		return nil, errors.Wrap(err, "collect facts")
+	}
+
+	return template.LoadDirs(ff, templateDirs...)
+}
+
+func renderTemplate(cmd *cmndr.Cmd, args []string) error {
+	if len(args) == 0 {
+		return nil
+	}
+
+	tpl, err := collectTemplates()
+	if err != nil {
+		return fmt.Errorf("collect templates: %w", err)
+	}
+
+	t := tpl.Lookup(args[0])
+	if t == nil {
+		return fmt.Errorf("no such template: %s", args[0])
+	}
+
+	if err := template.Render(os.Stdout, t); err != nil {
+		return fmt.Errorf("render template: %s: %w", t.Name(), err)
+	}
+
+	return nil
+}

@@ 0,0 1,3 @@
+{{define "baz"}}
+yup
+{{end}}<
\ No newline at end of file

@@ 0,0 1,3 @@
+{{define "baz" -}}
+{{yesno true}}
+{{end}}<
\ No newline at end of file

@@ 0,0 1,8 @@
+{{define "foo" -}}
+hello from {{ fact "os/name" }}
+
+The following packages are installed:
+{{range fact "packages/installed" | split "," -}}
+- {{.}}
+{{end}}
+{{end}}<
\ No newline at end of file

@@ 0,0 1,99 @@
+package template
+
+import (
+	"fmt"
+	"io"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+	"text/template"
+
+	"git.sr.ht/~nesv/govern/pkg/facts"
+
+	kerrors "k8s.io/apimachinery/pkg/util/errors"
+)
+
+func LoadDirs(ff *facts.Facts, dirnames ...string) (*template.Template, error) {
+	// Walk each directory in "templateDirs",
+	// and collect all of the files therein.
+	var (
+		files []string
+		errs  []error
+	)
+	for _, dir := range dirnames {
+		if !filepath.IsAbs(dir) {
+			var err error
+			dir, err = filepath.Abs(dir)
+			if err != nil {
+				errs = append(errs, fmt.Errorf("make path absolute: %w", err))
+				continue
+			}
+		}
+
+		info, err := os.Stat(dir)
+		if err != nil {
+			errs = append(errs, err)
+			continue
+		}
+		if !info.IsDir() {
+			errs = append(errs, fmt.Errorf("not a directory: %s", dir))
+			continue
+		}
+
+		if err := filepath.Walk(dir, func(pathname string, info fs.FileInfo, err error) error {
+			if err != nil {
+				return err
+			}
+
+			if info.IsDir() {
+				return nil
+			}
+
+			// Skip any files that are not immediately within the
+			// directory we are walking.
+			if d, _ := filepath.Split(pathname); strings.TrimPrefix(d, dir+string(filepath.Separator)) != "" {
+				return nil
+			}
+
+			files = append(files, pathname)
+			return nil
+		}); err != nil {
+			errs = append(errs, err)
+			continue
+		}
+	}
+
+	if len(files) == 0 {
+		return nil, nil
+	}
+
+	// Parse each file.
+	tpl, err := template.New("").Funcs(template.FuncMap{
+		"fact": getFact(ff),
+		"split": func(sep, s string) []string {
+			return strings.Split(s, sep)
+		},
+		"yesno": func(b bool) string {
+			if b {
+				return "yes"
+			}
+			return "no"
+		},
+	}).ParseFiles(files...)
+	if err != nil {
+		errs = append(errs, fmt.Errorf("parse template files: %w", err))
+	}
+
+	return tpl, kerrors.NewAggregate(errs)
+}
+
+func Render(w io.Writer, t *template.Template) error {
+	return t.Execute(w, nil)
+}
+
+func getFact(ff *facts.Facts) func(name string) (string, error) {
+	return func(name string) (string, error) {
+		return ff.Get(name)
+	}
+}