Cache parsed go-import and go-source data to prevent more than one HTTP request per dependency.

parsers/golang/exported.go

@@ -11,6 +11,8 @@ import (
 func Initialize() (parserinterface.Interface, string) {
 	log.Println("Initializing Golang projects parser")
 
+	goDatas = make(map[string]*godata)
+
 	p := &golangParser{}
 	return parserinterface.Interface(p), "golang"
 }

parsers/golang/godata.go

@@ -8,6 +8,7 @@ import (
 	"log"
 	"net/http"
 	"strings"
+	"sync"
 
 	// local
 	"go.dev.pztrn.name/glp/configuration"
@@ -15,6 +16,20 @@ import (
 	"go.dev.pztrn.name/glp/structs"
 )
 
+var (
+	goDatas      map[string]*godata
+	goDatasMutex sync.Mutex
+)
+
+// This structure used for caching data about dependencies and prevent
+// unneeded requests.
+type godata struct {
+	SourceURLDirTemplate  string
+	SourceURLFileTemplate string
+	VCSPath               string
+	VCS                   string
+}
+
 // attrValue returns the attribute value for the case-insensitive key
 // `name', or the empty string if nothing is found.
 func attrValue(attrs []xml.Attr, name string) string {
@@ -28,6 +43,20 @@ func attrValue(attrs []xml.Attr, name string) string {
 
 // Gets go-import and go-source data and fill it in dependency.
 func getGoData(dependency *structs.Dependency) {
+	// Check if information about that dependency already cached.
+	// Use cached data if so.
+	goDatasMutex.Lock()
+	depInfo, cached := goDatas[dependency.Name+"@"+dependency.Version]
+	goDatasMutex.Unlock()
+
+	if cached {
+		dependency.VCS.SourceURLDirTemplate = depInfo.SourceURLDirTemplate
+		dependency.VCS.SourceURLFileTemplate = depInfo.SourceURLFileTemplate
+		dependency.VCS.VCS = depInfo.VCS
+		dependency.VCS.VCSPath = depInfo.VCSPath
+		return
+	}
+
 	// Dependencies are imported using URL which can be called with
 	// "?go-get=1" parameter to obtain required VCS data.
 	req, _ := http.NewRequest("GET", "http://"+dependency.Name, nil)
@@ -101,4 +130,14 @@ func getGoData(dependency *structs.Dependency) {
 	if configuration.Cfg.Log.Debug {
 		log.Printf("go-import and go-source data parsed: %+v\n", dependency.VCS)
 	}
+
+	// Cache parsed data.
+	goDatasMutex.Lock()
+	goDatas[dependency.Name+"@"+dependency.Version] = &godata{
+		SourceURLDirTemplate:  dependency.VCS.SourceURLDirTemplate,
+		SourceURLFileTemplate: dependency.VCS.SourceURLFileTemplate,
+		VCS:                   dependency.VCS.VCS,
+		VCSPath:               dependency.VCS.VCSPath,
+	}
+	goDatasMutex.Unlock()
 }