Add --header option (#75)

Fixes #73

integration/cli_test.go

@@ -15,8 +15,8 @@ import (
 	"github.com/kr/pretty"
 )
 
-// In the following tests, there's a lot going on. Please have a look at the
-// following article for a longer explanation:
+// In these tests, there's a lot going on. Have a look at this article for a
+// longer explanation:
 // https://lucapette.me/writing/writing-integration-tests-for-a-go-cli-application
 
 var update = flag.Bool("update", false, "update golden files")
@@ -100,6 +100,12 @@ func TestCLI(t *testing.T) {
 			"default-format.golden",
 			false,
 		},
+		{
+			"default format with headers",
+			[]string{"--header", "int:42,42", "enum:foo,foo"},
+			"default-format-with-headers.golden",
+			false,
+		},
 		{
 			"unknown generators",
 			[]string{"madeupgenerator", "anothermadeupgenerator"},

integration/golden/default-format-with-headers.golden

@@ -0,0 +1,11 @@
+int enum
+42 foo
+42 foo
+42 foo
+42 foo
+42 foo
+42 foo
+42 foo
+42 foo
+42 foo
+42 foo

integration/golden/file-does-not-exist.golden

@@ -7,6 +7,7 @@ Usage: fakedata [option ...] generator...
   -g, --generator string              show help for a specific generator
   -G, --generators                    lists available generators
   -c, --generators-with-constraints   lists available generators with constraints
+  -H, --header                        adds headers row
   -h, --help                          shows help
   -l, --limit int                     limits rows up to n (default 10)
   -s, --separator string              specifies separator for the column format (default " ")

integration/golden/help.golden

@@ -5,6 +5,7 @@ Usage: fakedata [option ...] generator...
   -g, --generator string              show help for a specific generator
   -G, --generators                    lists available generators
   -c, --generators-with-constraints   lists available generators with constraints
+  -H, --header                        adds headers row
   -h, --help                          shows help
   -l, --limit int                     limits rows up to n (default 10)
   -s, --separator string              specifies separator for the column format (default " ")

integration/golden/path-empty.golden

@@ -7,6 +7,7 @@ Usage: fakedata [option ...] generator...
   -g, --generator string              show help for a specific generator
   -G, --generators                    lists available generators
   -c, --generators-with-constraints   lists available generators with constraints
+  -H, --header                        adds headers row
   -h, --help                          shows help
   -l, --limit int                     limits rows up to n (default 10)
   -s, --separator string              specifies separator for the column format (default " ")

integration/golden/unknown-format.golden

@@ -7,6 +7,7 @@ Usage: fakedata [option ...] generator...
   -g, --generator string              show help for a specific generator
   -G, --generators                    lists available generators
   -c, --generators-with-constraints   lists available generators with constraints
+  -H, --header                        adds headers row
   -h, --help                          shows help
   -l, --limit int                     limits rows up to n (default 10)
   -s, --separator string              specifies separator for the column format (default " ")

integration/golden/unknown-generators.golden

@@ -7,6 +7,7 @@ Usage: fakedata [option ...] generator...
   -g, --generator string              show help for a specific generator
   -G, --generators                    lists available generators
   -c, --generators-with-constraints   lists available generators with constraints
+  -H, --header                        adds headers row
   -h, --help                          shows help
   -l, --limit int                     limits rows up to n (default 10)
   -s, --separator string              specifies separator for the column format (default " ")

main.go

@@ -67,18 +67,19 @@ func findTemplate(path string) string {
 
 func main() {
 	var (
-		generatorsFlag  = flag.BoolP("generators", "G", false, "lists available generators")
-		generatorFlag   = flag.StringP("generator", "g", "", "show help for a specific generator")
+		completionFlag  = flag.StringP("completion", "C", "", "print shell completion function, pass shell name as argument (\"bash\", \"zsh\" or \"fish\")")
 		constraintsFlag = flag.BoolP("generators-with-constraints", "c", false, "lists available generators with constraints")
+		formatFlag      = flag.StringP("format", "f", "column", "generates rows in f format. Available formats: column|sql")
+		generatorFlag   = flag.StringP("generator", "g", "", "show help for a specific generator")
+		generatorsFlag  = flag.BoolP("generators", "G", false, "lists available generators")
+		headerFlag      = flag.BoolP("header", "H", false, "adds headers row")
+		helpFlag        = flag.BoolP("help", "h", false, "shows help")
 		limitFlag       = flag.IntP("limit", "l", 10, "limits rows up to n")
+		separatorFlag   = flag.StringP("separator", "s", " ", "specifies separator for the column format")
 		streamFlag      = flag.BoolP("stream", "S", false, "streams rows till the end of time")
-		formatFlag      = flag.StringP("format", "f", "column", "generates rows in f format. Available formats: column|sql")
 		tableFlag       = flag.StringP("table", "t", "TABLE", "table name of the sql format")
-		separatorFlag   = flag.StringP("separator", "s", " ", "specifies separator for the column format")
 		templateFlag    = flag.StringP("template", "T", "", "Use template as input")
-		completionFlag  = flag.StringP("completion", "C", "", "print shell completion function, pass shell name as argument (\"bash\", \"zsh\" or \"fish\")")
 		versionFlag     = flag.BoolP("version", "v", false, "shows version information")
-		helpFlag        = flag.BoolP("help", "h", false, "shows help")
 	)
 
 	flag.Usage = func() {
@@ -175,6 +176,10 @@ func main() {
 	fOut := bufio.NewWriter(os.Stdout)
 	defer fOut.Flush()
 
+	if *headerFlag {
+		columns.GenerateHeader(fOut, formatter)
+	}
+
 	if *streamFlag {
 		for {
 			columns.GenerateRow(fOut, formatter)

pkg/fakedata/column.go

@@ -64,3 +64,14 @@ func (columns Columns) GenerateRow(f io.Writer, formatter Formatter) {
 
 	fmt.Fprintf(f, "%s\n", formatter.Format(columns, values))
 }
+
+// GenerateRow generates an header row using column names
+// in the specified format
+func (columns Columns) GenerateHeader(f io.Writer, formatter Formatter) {
+	values := make([]string, len(columns))
+	for i, column := range columns {
+		values[i] = column.Name
+	}
+
+	fmt.Fprintf(f, "%s\n", formatter.Format(columns, values))
+}