cmd/htpacker: add --content-type flag

This allows overriding the content-type of files being packed using the
ad-hoc method (not YAML spec).

cmd/htpacker/pack.go

@@ -16,6 +16,20 @@ import (
 var packCmd = &cobra.Command{
 	Use:   "pack",
 	Short: "creates a packfile from a YAML spec or set of files/dirs",
+	Long: `When given a YAML spec file (a template for which can be generated
+with the "yaml" command), files will be packed exactly as per the spec. The
+--content-type flag cannot be used and no extra files can be specified.
+
+When given a list of files and directories to pack, the content type for each
+file will be automatically detected. It is possible to override the content
+type by specifying one or more --content-type flags. These take an argument in
+the form "pattern:content/type". The pattern is matched using common glob
+(* = wildcard), very similar to .gitignore. If the pattern contains any
+directory names, these must match the final components of the file to pack's
+path. If the pattern starts with a "/", then the full path must be matched
+exactly.
+`,
+
 	RunE: func(c *cobra.Command, args []string) error {
 		// convert "out" to an absolute path, so that it will still
 		// work after chdir
@@ -51,6 +65,16 @@ var packCmd = &cobra.Command{
 			}
 		}
 
+		// parse content-type globs
+		ctGlobList, err := c.Flags().GetStringArray("content-type")
+		if err != nil {
+			return err
+		}
+		ctGlobs, err := parseGlobs(ctGlobList)
+		if err != nil {
+			return err
+		}
+
 		// if "spec" is not present, then we expect a list of input
 		// files, and we'll build a spec from them
 		if spec == "" {
@@ -58,12 +82,16 @@ var packCmd = &cobra.Command{
 				return errors.New("need --yaml, " +
 					"or one or more filenames")
 			}
-			err = PackFiles(c, args, out)
+			err = PackFiles2(c, args, ctGlobs, out)
 		} else {
 			if len(args) != 0 {
 				return errors.New("cannot specify files " +
 					"when using --yaml")
 			}
+			if ctGlobs != nil {
+				return errors.New("cannot specify --content-type " +
+					"when using --yaml")
+			}
 			err = PackSpec(c, spec, out)
 		}
 		if err != nil {
@@ -83,13 +111,20 @@ func init() {
 		"YAML specification file (if not present, just pack files)")
 	packCmd.Flags().StringP("chdir", "C", "",
 		"Change to directory before searching for input files")
+	packCmd.Flags().StringArrayP("content-type", "", nil,
+		"Override content type for pattern, e.g. \"*.foo=bar/baz\" (like .gitignore)")
 }
 
 func PackFiles(c *cobra.Command, args []string, out string) error {
+	return PackFiles2(c, args, nil, out)
+}
+
+func PackFiles2(c *cobra.Command, args []string, ctGlobs ctGlobList, out string) error {
 	ftp, err := filesFromList(args)
 	if err != nil {
 		return err
 	}
+	ctGlobs.ApplyContentTypes(ftp)
 
 	return doPack(ftp, out)
 }