/funcs. /environment. /readme.

Author: nicerobot

README.md

@@ -10,7 +10,15 @@ Supports providing top-level name/value pairs on the command line:
 
     renderizer --name=value --top=first template-file
 
-**NOTE:** that _all_ parameter values are provided `name=value`.
+Sets:
+
+    Name: value
+    Top: first
+
+**NOTE:**
+
+- Template values are provided `--name=value`.
+- Renderizer controls are provided using `-NAME[=value]`.
 
 ## Example
 
@@ -20,21 +28,21 @@ First:
     cd renderizer
     go build
 
-Generate the master pod.yaml:
+Render the `pod.yaml` using values from `test/.renderizer.yaml`:
 
     renderizer -S=test/.renderizer.yaml test/pod.yaml
 
- or, set `RENDERIZER` in the environment:
+Or set `RENDERIZER` in the environment:
 
     RENDERIZER=test/.renderizer.yaml renderizer test/pod.yaml
 
-alternatively, it'll try `.renderizer.yaml` in the current directory.
+Alternatively, it'll try `.renderizer.yaml` in the current directory.
 
     (cd test; renderizer pod.yaml)
 
-Generate the dev pod.yaml (after `cd test/`):
+Next, override the `deployment` value to render the "dev" `pod.yaml` (after `cd test/`):
 
-    renderizer --deployment=dev pod.yaml
+    renderizer --deployment=dev --name='spaced out' pod.yaml
 
 ## Configuration
 
@@ -65,21 +73,22 @@ Control the missingkeys template-engine option:
 
 ### Environment `-E=`
 
-Add the environment to the variables map as `_env`:
-
-    renderizer -E template-file
-
-or name the map key:
-
-    renderizer -E=environ template-file
-
-## Functions
-
-### `add`
-### `inc`
-### `now`
-### `lower`
-### `upper`
-### `trim`
-### `trimLeft`
-### `trimRight`
+Provide a default value for missing environment variables:
+
+    renderizer -E=--missing-- template-file
+
+## Template Functions
+
+- `add` - `func(a, b int) int`
+- `cleanse` - `func(s string) string` - remove `[^[:alpha:]]`
+- `commandLine` - `func() string` the command line
+- `environment` - `map[string]string` - the runtime environment
+- `inc` - `func(a int) int`
+- `join` - `func(a []interface, sep string) string`
+- `lower` - `strings.ToLower`
+- `now` - `time.Now`
+- `replace` - `strings.Replace`
+- `trim` - `strings.Trim`
+- `trimLeft` - `strings.TrimLeft`
+- `trimRight` - `strings.TrimRight`
+- `upper` - `strings.ToUpper`

TODO.md

@@ -1,7 +1,12 @@
-- [ ] URL support
+- URL support
   - [ ] settings
   - [ ] templates
-- [ ] templates on stdin
-- [ ] modes
+- input
+  - [ ] templates on stdin
+- modes
   - [ ] HTML
   - [x] text
+- functions
+  - [x] environment
+  - [x] commandLine
+  - [ ] osquery

func.go

@@ -1,19 +1,63 @@
 package main
 
 import (
+	"fmt"
+	"os"
+	"regexp"
 	"strings"
 	"text/template"
 	"time"
 )
 
 //
 var funcs = template.FuncMap{
-	"add":       func(a, b int) int { return a + b },
-	"inc":       func(a int) int { return a + 1 },
-	"now":       func() time.Time { return time.Now().UTC() },
-	"lower":     func(s string) string { return strings.ToLower(s) },
-	"upper":     func(s string) string { return strings.ToUpper(s) },
-	"trim":      func(s string, cut string) string { return strings.Trim(s, cut) },
-	"trimLeft":  func(s string, cut string) string { return strings.TrimLeft(s, cut) },
-	"trimRight": func(s string, cut string) string { return strings.TrimRight(s, cut) },
+	"add":         func(a, b int) int { return a + b },
+	"cleanse":     cleanse(`[^[:alpha:]]`),
+	"commandLine": func() string { return settings.CommandLine },
+	"environment": environment(),
+	"inc":         func(a int) int { return a + 1 },
+	"join":        joiner,
+	"lower":       strings.ToLower,
+	"now":         time.Now,
+	"replace":     strings.Replace,
+	"trim":        strings.Trim,
+	"trimLeft":    strings.TrimLeft,
+	"trimRight":   strings.TrimRight,
+	"upper":       strings.ToUpper,
+}
+
+//
+func joiner(y []interface{}, sep string) (s string) {
+	if y == nil {
+		return
+	}
+	i := make([]string, len(y))
+	for j, z := range y {
+		i[j] = fmt.Sprintf("%v", z)
+	}
+	return strings.Join(i, sep)
+}
+
+//
+func cleanse(r string) func(string) string {
+	re := regexp.MustCompile(r)
+	return func(s string) string {
+		return re.ReplaceAllString(s, "")
+	}
+}
+
+//
+func environment() func(string) string {
+	env := make(map[string]string)
+	for _, item := range os.Environ() {
+		splits := strings.Split(item, "=")
+		env[splits[0]] = splits[1]
+	}
+	return func(n string) string {
+		v, exists := env[n]
+		if !exists {
+			v = settings.Environment
+		}
+		return v
+	}
 }

main.go

@@ -7,13 +7,15 @@ import (
 	"io/ioutil"
 	"log"
 	"os"
+	"path/filepath"
 	"strings"
 	"text/template"
 	"time"
 
 	"gopkg.in/yaml.v2"
 )
 
+//
 func usage(out io.Writer) {
 	fmt.Fprintf(out, `usage: renderizer [options] [--name=value...] template...
 options:
@@ -47,6 +49,8 @@ type Settings struct {
 	Debugging bool
 	//
 	Verbose bool
+	//
+	CommandLine string
 }
 
 //
@@ -59,10 +63,17 @@ var settings = Settings{
 //
 func main() {
 
+	if len(os.Args) == 1 {
+		usage(os.Stdout)
+		return
+	}
+
 	vars := map[string]interface{}{}
 	load := map[string]interface{}{}
 	args := []string{}
 
+	settings.CommandLine = commandLine()
+
 	// Initialize some settings from the environment.
 
 	if m, exists := os.LookupEnv("RENDERIZER_MISSINGKEY"); exists {
@@ -93,23 +104,21 @@ func main() {
 			usage(os.Stdout)
 			return
 		case 's', 'S':
-			nv := strings.Split(arg, "=")
+			nv := strings.SplitN(arg, "=", 2)
 			if len(nv) != 1 {
 				settings.Config = nv[1]
 			}
 		case 'e', 'E':
-			nv := strings.Split(arg, "=")
-			if len(nv) == 1 {
-				settings.Environment = "_env"
-			} else {
+			nv := strings.SplitN(arg, "=", 2)
+			if len(nv) != 1 {
 				settings.Environment = nv[1]
 			}
 		case 'v', 'V':
 			settings.Verbose = true
 		case 'd', 'D':
 			settings.Debugging = true
 		case 'm', 'M':
-			nv := strings.Split(arg, "=")
+			nv := strings.SplitN(arg, "=", 2)
 			if len(nv) == 1 {
 				settings.MissingKey = "error"
 			} else {
@@ -125,20 +134,6 @@ func main() {
 		settings.MissingKey = "error"
 	}
 
-	// Add the environment to the variables.
-
-	if settings.Environment != "" {
-		env := make(map[string]string)
-		for _, item := range os.Environ() {
-			splits := strings.Split(item, "=")
-			env[splits[0]] = splits[1]
-		}
-		vars[settings.Environment] = env
-		if settings.Verbose {
-			log.Printf("environment: %+v", settings.Environment)
-		}
-	}
-
 	// Load the settings.
 
 	forced := false
@@ -183,7 +178,7 @@ func main() {
 			}
 
 			arg = strings.TrimLeft(arg, "-")
-			nv := strings.Split(arg, "=")
+			nv := strings.SplitN(arg, "=", 2)
 			n := nv[0]
 			i += 1
 
@@ -337,3 +332,29 @@ func main() {
 		fmt.Println(string(sqlBuffer.Bytes()))
 	}
 }
+
+// Reproduce a command line string that reflects a usable command line.
+func commandLine() string {
+
+	quoter := func(e string) string {
+		if !strings.Contains(e, " ") {
+			return e
+		}
+		p := strings.SplitN(e, "=", 2)
+		if strings.Contains(p[0], " ") {
+			p[0] = `"` + strings.Replace(p[0], `"`, `\"`, -1) + `"`
+		}
+		if len(p) == 1 {
+			return p[0]
+		}
+		return p[0] + `="` + strings.Replace(p[1], `"`, `\"`, -1) + `"`
+	}
+	each := func(s []string) (o []string) {
+		o = make([]string, len(s))
+		for i, t := range s {
+			o[i] = quoter(t)
+		}
+		return
+	}
+	return filepath.Base(os.Args[0]) + " " + strings.Join(each(os.Args[1:]), " ")
+}

test/pod.yaml

@@ -1,7 +1,10 @@
+# Generated: {{now.UTC.Format "2006-01-02T15:04:05MST"}}
+#      With: {{commandLine}}
+#      From: {{environment "USER"}}@{{environment "HOST"}}:{{environment "PWD"}}
 apiVersion: v1
 kind: Pod
 metadata:
-  name: {{lower .Name}}
+  name: {{replace .Name " " "_" -1 | cleanse | lower}}
   namespace: {{.App}}-{{.Deployment}}
   labels:
     app: {{.App}}