feat(envc): add support for converting current process environment to YAML

Enhance the `envc convert` command to allow conversion of the current process environment to YAML format. Update README with usage examples and clarify input options. Add tests to ensure correct functionality for environment variable handling.

.vscode/launch.json

@@ -0,0 +1,21 @@
+{
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "name": "Go: Launch cmd/ (main)",
+      "type": "go",
+      "request": "launch",
+      "mode": "auto",
+      "program": "${workspaceFolder}/cmd",
+      "cwd": "${workspaceFolder}"
+    },
+    {
+      "name": "Go: Debug tests in current file's package",
+      "type": "go",
+      "request": "launch",
+      "mode": "test",
+      "program": "${fileDirname}",
+      "cwd": "${workspaceFolder}"
+    }
+  ]
+}

README.md

@@ -85,6 +85,24 @@ b, _ := json.New().Marshal(m)
 os.WriteFile("out.json", b, 0o644)
 ```
 
+### 4. Current process environment → YAML (library)
+
+```go
+ctx := context.Background()
+m, err := env.New(env.WithCurrentEnvironment()).Map(ctx)
+if err != nil {
+	return err
+}
+b, err := yaml.New().Marshal(m)
+if err != nil {
+	return err
+}
+_, _ = os.Stdout.Write(b)
+```
+
+Same map as `envc convert --from env --to yaml --input environ` (nested keys come from
+splitting `VAR_NAME` on `_`, then **lower+alnum** normalization).
+
 ## CLI: `envc`
 
 Install the binary from [**Install**](#install) (`go install …/cmd/envc@latest`). Every
@@ -109,7 +127,16 @@ envc version
 ### `convert`
 
 One input → normalize keys → one output. Defaults: **`--input -`**, **`--output -`**
-(stdin / stdout).
+(stdin / stdout). Use **`--input environ`** with **`--from env`** to read **`os.Environ()`**
+(snapshot at run time), then emit **`--to`** (YAML, JSON, etc.) on stdout—no stdin.
+
+```bash
+# Current process environment → nested YAML on stdout (may include secrets; mask before sharing)
+envc convert --from env --to yaml --input environ --output -
+
+# Same snapshot as minified JSON
+envc convert --from env --to json --input environ
+```
 
 ```bash
 # Helm-style values file → JSON on the terminal (redirect to a file if you prefer)
@@ -208,6 +235,9 @@ set +a
 ### Stdin, URLs, and EOF
 
 ```bash
+# Process environment (not stdin): use --input environ with --from env (see `convert` above)
+envc convert --from env --to yaml --input environ
+
 # Explicit stdin redirect (reads until EOF)
 envc convert --from yaml --to json --input - --output - <./service.yaml
 

cmd/envc/convert.go

@@ -22,7 +22,7 @@ func RunConvert(args []string, stdin io.Reader, stdout, stderr io.Writer) int {
 	fs.SetOutput(stderr)
 	from := fs.String("from", "", "source format: yaml|json|toml|ini|env")
 	to := fs.String("to", "", "target format: yaml|json|toml|ini|env")
-	input := fs.String("input", "-", "input path, URL, or - for stdin")
+	input := fs.String("input", "-", "input path, URL, - for stdin, or \"environ\" for current process env (requires --from env)")
 	output := fs.String("output", "-", "output path or - for stdout")
 	if err := fs.Parse(args); err != nil {
 		return 2
@@ -32,16 +32,31 @@ func RunConvert(args []string, stdin io.Reader, stdout, stderr io.Writer) int {
 		return 2
 	}
 	ctx := context.Background()
-	src := openSource(*input, stdin)
-	b, err := bytesutil.ReadAll(ctx, src)
-	if err != nil {
-		_, _ = fmt.Fprintf(stderr, "convert: read: %v\n", err)
-		return 1
-	}
-	m, err := loadMapFromBytes(ctx, *from, b)
-	if err != nil {
-		_, _ = fmt.Fprintf(stderr, "convert: parse: %v\n", err)
-		return 1
+	var m map[string]any
+	var err error
+	if *input == "environ" {
+		if *from != "env" {
+			_, _ = fmt.Fprintln(stderr, "convert: --input environ only works with --from env")
+			return 2
+		}
+		m, err = env.New(env.WithCurrentEnvironment()).Map(ctx)
+		if err != nil {
+			_, _ = fmt.Fprintf(stderr, "convert: environ: %v\n", err)
+			return 1
+		}
+	} else {
+		src := openSource(*input, stdin)
+		var b []byte
+		b, err = bytesutil.ReadAll(ctx, src)
+		if err != nil {
+			_, _ = fmt.Fprintf(stderr, "convert: read: %v\n", err)
+			return 1
+		}
+		m, err = loadMapFromBytes(ctx, *from, b)
+		if err != nil {
+			_, _ = fmt.Fprintf(stderr, "convert: parse: %v\n", err)
+			return 1
+		}
 	}
 	outb, err := marshalMap(*to, m)
 	if err != nil {

cmd/envc/convert_test.go

@@ -8,6 +8,33 @@ import (
 	"testing"
 )
 
+func TestRunConvert_EnvironToYAML(t *testing.T) {
+	t.Setenv("ENVC_TEST_PUBLISH", "xyzzy")
+	var stdout, stderr bytes.Buffer
+	code := RunConvert([]string{
+		"--from", "env", "--to", "yaml",
+		"--input", "environ", "--output", "-",
+	}, strings.NewReader(""), &stdout, &stderr)
+	if code != 0 {
+		t.Fatalf("stderr: %s", stderr.String())
+	}
+	out := stdout.String()
+	if !strings.Contains(out, "xyzzy") {
+		t.Fatalf("expected value in yaml out: %s", out)
+	}
+}
+
+func TestRuknConvert_EnvironRequiresFromEnv(t *testing.T) {
+	var stdout, stderr bytes.Buffer
+	code := RunConvert([]string{
+		"--from", "yaml", "--to", "json",
+		"--input", "environ", "--output", "-",
+	}, strings.NewReader(""), &stdout, &stderr)
+	if code != 2 {
+		t.Fatalf("expected exit 2, got %d stderr=%s", code, stderr.String())
+	}
+}
+
 func TestRunConvert_TOMLToJSON(t *testing.T) {
 	var stdout, stderr bytes.Buffer
 	stdin := strings.NewReader("[app]\nport = 8080\n")