Cavebeavis/add printenvs

README.md

@@ -161,7 +161,7 @@ prefixing them (`field_name=<your_value>`). The `--template` flag allows you to
 specify a custom format for the tag value to be applied.
 
 ```
-$ gomodifytags -file demo.go -struct Server -add-tags gaum -template "field_name=$field" 
+$ gomodifytags -file demo.go -struct Server -add-tags gaum -template 'field_name=$field' 
 ```
 
 ```go
@@ -183,6 +183,7 @@ The `$field` is a special keyword that is replaced by the struct tag's value
 We currently support the following transformations:
 
 * `snakecase`: `"BaseDomain"` -> `"base_domain"`
+* `envcase`: `"BaseDomain"` -> `"BASE_DOMAIN"`
 * `camelcase`: `"BaseDomain"` -> `"baseDomain"`
 * `lispcase`:  `"BaseDomain"` -> `"base-domain"`
 * `pascalcase`:  `"BaseDomain"` -> `"BaseDomain"`
@@ -378,7 +379,7 @@ type Server struct {
 }
 ```
 
-Lastly, to remove all options without explicitly defining the keys and names,
+To remove all options without explicitly defining the keys and names,
 we can use the `-clear-options` flag. The following example will remove all
 options for the given struct:
 
@@ -400,6 +401,16 @@ type Server struct {
 }
 ```
 
+**Environment Variables**
+
+In order to print an `.env` file template, use the `-print-envs` flag to default
+to `./.env` or add `-envs-filename /path/to/file` and it will create a new file
+with the path and name specified.
+
+```bash
+$ gomodifytags -file test-fixtures/all_structs.input -all -add-tags conf -template 'env:$field,noprint' -transform envcase -envs-filename 'path/to/.env' -print-envs
+```
+
 ## Line based modification
 
 So far all examples used the `-struct` flag. However we also can pass the line

go.mod

@@ -1,9 +1,9 @@
 module github.com/fatih/gomodifytags
 
+go 1.16
+
 require (
 	github.com/fatih/camelcase v1.0.0
 	github.com/fatih/structtag v1.2.0
-	golang.org/x/tools v0.0.0-20180824175216-6c1c5e93cdc1
+	golang.org/x/tools v0.1.5
 )
-
-go 1.13

go.sum

@@ -2,5 +2,30 @@ github.com/fatih/camelcase v1.0.0 h1:hxNvNX/xYBp0ovncs8WyWZrOrpBNub/JfaMvbURyft8
 github.com/fatih/camelcase v1.0.0/go.mod h1:yN2Sb0lFhZJUdVvtELVWefmrXpuZESvPmqwoZc+/fpc=
 github.com/fatih/structtag v1.2.0 h1:/OdNE99OxoI/PqaW/SuSK9uxxT3f/tcSZgon/ssNSx4=
 github.com/fatih/structtag v1.2.0/go.mod h1:mBJUNpUnHmRKrKlQQlmCrh5PuhftFbNv8Ys4/aAZl94=
-golang.org/x/tools v0.0.0-20180824175216-6c1c5e93cdc1 h1:EAPsk8kfGCjxQagrkWjzXlUWe2p3gj5MknO+z2o9GKc=
-golang.org/x/tools v0.0.0-20180824175216-6c1c5e93cdc1/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+github.com/yuin/goldmark v1.3.5/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/mod v0.4.2 h1:Gz96sIWK3OalVv/I/qNygP42zyoKp3xptRVCWRFEBvo=
+golang.org/x/mod v0.4.2/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4/go.mod h1:p54w0d4576C0XHj96bSt6lcn1PtDYWL6XObtHCRCNQM=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210510120138-977fb7262007 h1:gG67DSER+11cZvqIMb8S8bt0vZtiN6xWYARwirrOSfE=
+golang.org/x/sys v0.0.0-20210510120138-977fb7262007/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.1.5 h1:ouewzE6p+/VEB31YYnTbEJdi8pFqKp4P4n85vwo3DHA=
+golang.org/x/tools v0.1.5/go.mod h1:o0xws9oXOQQZyjljx8fwUC0k7L1pTE6eaCbjGeHmOkk=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 h1:go1bK/D/BFZV2I8cIQd1NKEZ+0owSTG1fDTci4IqFcE=
+golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

main.go

@@ -69,16 +69,19 @@ type config struct {
 	valueFormat string
 	clear       bool
 	clearOption bool
+
+	printEnvFile     bool
+	printEnvFileName string
 }
 
 func main() {
-	if err := realMain(); err != nil {
+	if err := run(); err != nil {
 		fmt.Fprintln(os.Stderr, err.Error())
 		os.Exit(1)
 	}
 }
 
-func realMain() error {
+func run() error {
 	cfg, err := parseConfig(os.Args[1:])
 	if err != nil {
 		if err == flag.ErrHelp {
@@ -114,6 +117,12 @@ func realMain() error {
 		return err
 	}
 
+	if cfg.printEnvFile {
+		if err := cfg.printEnvs(out); err != nil {
+			return err
+		}
+	}
+
 	fmt.Println(out)
 	return nil
 }
@@ -150,13 +159,13 @@ func parseConfig(args []string) (*config, error) {
 		flagSkipUnexportedFields = flag.Bool("skip-unexported", false, "Skip unexported fields")
 		flagTransform            = flag.String("transform", "snakecase",
 			"Transform adds a transform rule when adding tags."+
-				" Current options: [snakecase, camelcase, lispcase, pascalcase, keep]")
+				" Current options: [snakecase, envcase, camelcase, lispcase, pascalcase, keep]")
 		flagSort = flag.Bool("sort", false,
 			"Sort sorts the tags in increasing order according to the key name")
 
 		// formatting
 		flagFormatting = flag.String("template", "",
-			"Format the given tag's value. i.e: \"column:$field\", \"field_name=$field\"")
+			"Format the given tag's value. i.e: 'column:$field', 'field_name=$field'")
 
 		// option flags
 		flagRemoveOptions = flag.String("remove-options", "",
@@ -166,6 +175,12 @@ func parseConfig(args []string) (*config, error) {
 			"Clear all tag options")
 		flagAddOptions = flag.String("add-options", "",
 			"Add the options per given key. i.e: json=omitempty,hcl=squash")
+
+		// print envfile template
+		flagPrintEnvFile = flag.Bool("print-envs", false,
+			"Prints the environmental variables in default file '.env' for use as an env template")
+		flagPrintEnvFileName = flag.String("envs-filename", ".env", 
+			"Filename where this should save the environmental variable template -- note will truncate file")
 	)
 
 	// this fails if there are flags re-defined with the same name.
@@ -195,6 +210,8 @@ func parseConfig(args []string) (*config, error) {
 		valueFormat:          *flagFormatting,
 		override:             *flagOverride,
 		skipUnexportedFields: *flagSkipUnexportedFields,
+		printEnvFile:         *flagPrintEnvFile,
+		printEnvFileName:     *flagPrintEnvFileName,
 	}
 
 	if *flagModified {
@@ -255,7 +272,7 @@ func (c *config) findSelection(node ast.Node) (int, int, error) {
 	}
 }
 
-func (c *config) process(fieldName, tagVal string) (string, error) {
+func (c *config) process(structName, fieldName, tagVal string) (string, error) {
 	var tag string
 	if tagVal != "" {
 		var err error
@@ -279,7 +296,7 @@ func (c *config) process(fieldName, tagVal string) (string, error) {
 	tags = c.clearTags(tags)
 	tags = c.clearOptions(tags)
 
-	tags, err = c.addTags(fieldName, tags)
+	tags, err = c.addTags(structName, fieldName, tags)
 	if err != nil {
 		return "", err
 	}
@@ -373,33 +390,40 @@ func (c *config) addTagOptions(tags *structtag.Tags) (*structtag.Tags, error) {
 	return tags, nil
 }
 
-func (c *config) addTags(fieldName string, tags *structtag.Tags) (*structtag.Tags, error) {
+func (c *config) addTags(structName, fieldName string, tags *structtag.Tags) (*structtag.Tags, error) {
 	if c.add == nil || len(c.add) == 0 {
 		return tags, nil
 	}
 
-	splitted := camelcase.Split(fieldName)
+	split := camelcase.Split(fieldName)
 	name := ""
 
 	unknown := false
 	switch c.transform {
 	case "snakecase":
-		var lowerSplitted []string
-		for _, s := range splitted {
-			lowerSplitted = append(lowerSplitted, strings.ToLower(s))
+		var lowerSplit []string
+		for _, s := range split {
+			lowerSplit = append(lowerSplit, strings.ToLower(s))
+		}
+
+		name = strings.Join(lowerSplit, "_")
+	case "envcase":
+		upperSplit := []string{strings.ToUpper(structName)}
+		for _, s := range split {
+			upperSplit = append(upperSplit, strings.ToUpper(s))
 		}
 
-		name = strings.Join(lowerSplitted, "_")
+		name = strings.Join(upperSplit, "_")
 	case "lispcase":
-		var lowerSplitted []string
-		for _, s := range splitted {
-			lowerSplitted = append(lowerSplitted, strings.ToLower(s))
+		var lowerSplit []string
+		for _, s := range split {
+			lowerSplit = append(lowerSplit, strings.ToLower(s))
 		}
 
-		name = strings.Join(lowerSplitted, "-")
+		name = strings.Join(lowerSplit, "-")
 	case "camelcase":
 		var titled []string
-		for _, s := range splitted {
+		for _, s := range split {
 			titled = append(titled, strings.Title(s))
 		}
 
@@ -408,7 +432,7 @@ func (c *config) addTags(fieldName string, tags *structtag.Tags) (*structtag.Tag
 		name = strings.Join(titled, "")
 	case "pascalcase":
 		var titled []string
-		for _, s := range splitted {
+		for _, s := range split {
 			titled = append(titled, strings.Title(s))
 		}
 
@@ -424,10 +448,10 @@ func (c *config) addTags(fieldName string, tags *structtag.Tags) (*structtag.Tag
 	}
 
 	for _, key := range c.add {
-		splitted = strings.SplitN(key, ":", 2)
-		if len(splitted) >= 2 {
-			key = splitted[0]
-			name = strings.Join(splitted[1:], "")
+		split = strings.SplitN(key, ":", 2)
+		if len(split) >= 2 {
+			key = split[0]
+			name = strings.Join(split[1:], "")
 		} else if unknown {
 			// the user didn't pass any value but want to use an unknown
 			// transform. We don't return above in the default as the user
@@ -456,7 +480,7 @@ func (c *config) addTags(fieldName string, tags *structtag.Tags) (*structtag.Tag
 
 // collectStructs collects and maps structType nodes to their positions
 func collectStructs(node ast.Node) map[token.Pos]*structType {
-	structs := make(map[token.Pos]*structType, 0)
+	structs := make(map[token.Pos]*structType)
 
 	collectStructs := func(n ast.Node) bool {
 		var t ast.Expr
@@ -649,8 +673,8 @@ func (c *config) fieldSelection(st *ast.StructType) (int, int, error) {
 	}
 
 	if encField == nil {
-		return 0, 0, errors.New(fmt.Sprintf("struct %q doesn't have field name %q",
-			c.structName, c.fieldName))
+		return 0, 0, fmt.Errorf("struct %q doesn't have field name %q",
+			c.structName, c.fieldName)
 	}
 
 	start := c.fset.Position(encField.Pos()).Line
@@ -703,8 +727,14 @@ func isPublicName(name string) bool {
 // positions
 func (c *config) rewrite(node ast.Node, start, end int) (ast.Node, error) {
 	errs := &rewriteErrors{errs: make([]error, 0)}
+
+	var structName string
 
 	rewriteFunc := func(n ast.Node) bool {
+		if typeSpec, ok := n.(*ast.TypeSpec); ok {
+			structName = typeSpec.Name.Name
+		}
+
 		x, ok := n.(*ast.StructType)
 		if !ok {
 			return true
@@ -748,7 +778,7 @@ func (c *config) rewrite(node ast.Node, start, end int) (ast.Node, error) {
 				f.Tag = &ast.BasicLit{}
 			}
 
-			res, err := c.process(fieldName, f.Tag.Value)
+			res, err := c.process(structName, fieldName, f.Tag.Value)
 			if err != nil {
 				errs.Append(fmt.Errorf("%s:%d:%d:%s",
 					c.fset.Position(f.Pos()).Filename,
@@ -903,3 +933,47 @@ func deref(x ast.Expr) ast.Expr {
 	}
 	return x
 }
+
+func (c *config) printEnvs(in string) error {
+	split := strings.Split(in, "\n")
+
+	// Looking for something in the pattern of
+	//    Field   {type} `conf:"env:ENV_VARIABLE,no-print"`
+	// to extract the ENV_VARIABLE part.
+	var envs []string
+	for _, val := range split {
+		match := "env:"
+		idx := strings.Index(val, match)
+		if idx != -1 {
+			val = val[idx + len(match):]
+
+			// Find the ending double quote to grab from example: ENV_VARIABLE,noprint.
+			idx = strings.Index(val, "\"")
+			if idx != -1 {
+				val = val[:idx]
+
+				// Find if there is a comma "," from example: ENV_VARIABLE.
+				idx = strings.Index(val, ",")
+				if idx != -1 {
+					val = val[:idx]
+				}
+
+				// Make sure there are no empty spaces in the environmental variable.
+				val = strings.TrimSpace(val)
+
+				env := val + "="
+				envs = append(envs, env)
+			}
+		}
+	}
+
+	f, err := os.Create(c.printEnvFileName)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	_, err = f.WriteString(strings.Join(envs, "\n"))
+
+	return err
+}

main_test.go

@@ -302,6 +302,16 @@ func TestRewrite(t *testing.T) {
 				transform: "camelcase",
 			},
 		},
+		{
+			file: "line_envcase_add",
+			cfg: &config{
+				add:       []string{"conf"},
+				output:    "source",
+				line:      "4,5",
+				transform: "envcase",
+				valueFormat: "env:$field",
+			},
+		},
 		{
 			file: "line_value_add",
 			cfg: &config{

test-fixtures/line_envcase_add.golden

@@ -0,0 +1,7 @@
+package foo
+
+type foo struct {
+	bar       string `conf:"env:FOO_BAR"`
+	MyExample bool   `conf:"env:FOO_MY_EXAMPLE"`
+	MyAnother []string
+}

test-fixtures/line_envcase_add.input

@@ -0,0 +1,7 @@
+package foo
+
+type foo struct {
+	bar       string
+	MyExample bool
+	MyAnother []string
+}