Cache cloud-api response for 24h to improve responsiveness

Author: cmaglie

Diff for: commands/board/list.go

@@ -32,6 +32,7 @@ import (
 	"github.com/arduino/arduino-cli/arduino/discovery"
 	"github.com/arduino/arduino-cli/arduino/httpclient"
 	"github.com/arduino/arduino-cli/commands"
+	"github.com/arduino/arduino-cli/inventory"
 	rpc "github.com/arduino/arduino-cli/rpc/cc/arduino/cli/commands/v1"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
@@ -50,6 +51,39 @@ var (
 	validVidPid = regexp.MustCompile(`0[xX][a-fA-F\d]{4}`)
 )
 
+func cachedApiByVidPid(vid, pid string) ([]*rpc.BoardListItem, error) {
+	var resp []*rpc.BoardListItem
+
+	cacheKey := fmt.Sprintf("cache.builder-api.v3/boards/byvid/pid/%s/%s", vid, pid)
+	if cachedResp := inventory.Store.GetString(cacheKey + ".data"); cachedResp != "" {
+		ts := inventory.Store.GetTime(cacheKey + ".ts")
+		if time.Since(ts) < time.Hour*24 {
+			// Use cached response
+			if cachedResp == "ErrNotFound" {
+				return nil, ErrNotFound
+			}
+			if err := json.Unmarshal([]byte(cachedResp), &resp); err == nil {
+				return resp, nil
+			}
+		}
+	}
+
+	resp, err := apiByVidPid(vid, pid) // Perform API requrest
+
+	if err == ErrNotFound {
+		inventory.Store.Set(cacheKey+".data", "ErrNotFound")
+		inventory.Store.Set(cacheKey+".ts", time.Now())
+		inventory.WriteStore()
+	} else if err == nil {
+		if cachedResp, err := json.Marshal(resp); err == nil {
+			inventory.Store.Set(cacheKey+".data", string(cachedResp))
+			inventory.Store.Set(cacheKey+".ts", time.Now())
+			inventory.WriteStore()
+		}
+	}
+	return resp, err
+}
+
 func apiByVidPid(vid, pid string) ([]*rpc.BoardListItem, error) {
 	// ensure vid and pid are valid before hitting the API
 	if !validVidPid.MatchString(vid) {
@@ -116,7 +150,7 @@ func identifyViaCloudAPI(port *discovery.Port) ([]*rpc.BoardListItem, error) {
 	}
 
 	logrus.Debug("Querying builder API for board identification...")
-	return apiByVidPid(id.Get("vid"), id.Get("pid"))
+	return cachedApiByVidPid(id.Get("vid"), id.Get("pid"))
 }
 
 // identify returns a list of boards checking first the installed platforms or the Cloud API

Diff for: inventory/inventory.go

@@ -19,6 +19,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"sync"
 
 	"github.com/arduino/arduino-cli/i18n"
 	"github.com/gofrs/uuid"
@@ -77,9 +78,14 @@ func generateInstallationData() error {
 	return nil
 }
 
+var writeStoreMux sync.Mutex
+
 // WriteStore writes the current information from Store to configFilePath.
 // Returns err if it fails.
 func WriteStore() error {
+	writeStoreMux.Lock()
+	defer writeStoreMux.Unlock()
+
 	configPath := filepath.Dir(configFilePath)
 
 	// Create config dir if not present,