[minor] support filtering by version in pkg module

Closes #182

modules/pkg/doc.rst

@@ -20,6 +20,10 @@ on the agent system, identifying any packages matching the regular expression
 argument to `name`, and returning those packages along with their versions. In
 addition to this, the agent will also return what type of package was identified.
 
+It is also possible to optionally filter on the version, so the agent only returns
+packages which also match the given version. This can be done by supplying a
+regular expression to match against the package version as a `version` option.
+
 Currently the following package managers are supported for query on an agent system.
 
 * **RPM**: RPM based package managers, for Red Hat, CentOS, etc

modules/pkg/paramscreator.go

@@ -24,7 +24,11 @@ func printHelp(isCmd bool) {
 %sname <regexp>     - OS package search
                     ex: name linux-image
 		    query for installed OS packages matching expression
-`, dash)
+
+%sversion <regexp>  - Version string search
+                    ex: version ^1\..*
+		    optionally filter returned packages to include version
+`, dash, dash)
 }
 
 func (r *run) ParamsCreator() (interface{}, error) {
@@ -58,6 +62,8 @@ func (r *run) ParamsCreator() (interface{}, error) {
 		switch checkType {
 		case "name":
 			p.PkgMatch.Matches = append(p.PkgMatch.Matches, checkValue)
+		case "version":
+			p.VerMatch = checkValue
 		default:
 			fmt.Printf("Invalid method!\nTry 'help'\n")
 			continue
@@ -73,6 +79,7 @@ func (r *run) ParamsParser(args []string) (interface{}, error) {
 	var (
 		fs       flag.FlagSet
 		pkgMatch flagParam
+		verMatch string
 	)
 
 	if len(args) < 1 || args[0] == "" || args[0] == "help" {
@@ -82,6 +89,7 @@ func (r *run) ParamsParser(args []string) (interface{}, error) {
 
 	fs.Init("pkg", flag.ContinueOnError)
 	fs.Var(&pkgMatch, "name", "see help")
+	fs.StringVar(&verMatch, "version", "", "see help")
 	err := fs.Parse(args)
 	if err != nil {
 		return nil, err
@@ -89,6 +97,9 @@ func (r *run) ParamsParser(args []string) (interface{}, error) {
 
 	p := newParameters()
 	p.PkgMatch.Matches = pkgMatch
+	if verMatch != "" {
+		p.VerMatch = verMatch
+	}
 
 	r.Parameters = *p
 

modules/pkg/pkg.go

@@ -105,6 +105,17 @@ func (r *run) Run(in io.Reader) (resStr string) {
 			if !re.MatchString(y.Name) {
 				continue
 			}
+			// If optional version filter was supplied, filter on that
+			// as well
+			if r.Parameters.VerMatch != "" {
+				rev, err := regexp.Compile(r.Parameters.VerMatch)
+				if err != nil {
+					panic(err)
+				}
+				if !rev.MatchString(y.Version) {
+					continue
+				}
+			}
 			e.Packages = append(e.Packages, y)
 		}
 	}
@@ -127,6 +138,12 @@ func (r *run) ValidateParameters() (err error) {
 			return err
 		}
 	}
+	if r.Parameters.VerMatch != "" {
+		_, err = regexp.Compile(r.Parameters.VerMatch)
+		if err != nil {
+			return err
+		}
+	}
 	return
 }
 
@@ -172,6 +189,7 @@ type Statistics struct {
 
 type Parameters struct {
 	PkgMatch PkgMatch `json:"pkgmatch"` // List of strings to use as regexp package matches.
+	VerMatch string   `json:"vermatch"` // Optionally filter returned packages on version string
 }
 
 type PkgMatch struct {