feat: support local apps.json loading

This logic supports the following cases:

- Download a fresh apps.json and load it if missing
- Check if a local apps.json is old and get a fresh one if so
- Always save a local copy after downloading a fresh apps.json

The http.Head() call is faster than a http.Get() call (only carries back
respones headers) and aims to make the more general case more
performant: you have the latest copy of the apps.json and don't need to
download another one. This a direct port of our Bash implementation
logic.

Closes #9.

cli/recipe.go

@@ -3,53 +3,60 @@ package cli
 import (
 	"encoding/json"
 	"fmt"
+	"io/ioutil"
 	"net/http"
+	"os"
 	"sort"
 	"time"
 
+	"coopcloud.tech/abra/config"
+
 	"github.com/sirupsen/logrus"
 	"github.com/urfave/cli/v2"
 )
 
-type Image struct {
+type AppImage struct {
 	Image  string `json:"image"`
 	Rating string `json:"rating"`
 	Source string `json:"source"`
 	URL    string `json:"url"`
 }
 
-type AppFeatureSpec struct {
-	Backups     string `json:"backups"`
-	Email       string `json:"email"`
-	Healthcheck string `json:"healthcheck"`
-	Image       Image  `json:"image"`
-	Status      int    `json:"status"`
-	Tests       string `json:"tests"`
+type Feature struct {
+	Backups     string   `json:"backups"`
+	Email       string   `json:"email"`
+	Healthcheck string   `json:"healthcheck"`
+	Image       AppImage `json:"image"`
+	Status      int      `json:"status"`
+	Tests       string   `json:"tests"`
 }
 
-type AppVersionSpec struct {
+type Version struct {
 	Digest string `json:"digest"`
 	Image  string `json:"image"`
 	Tag    string `json:"tag"`
 }
 
-type AppSpec struct {
-	Category      string                               `json:"category"`
-	DefaultBranch string                               `json:"default_branch"`
-	Description   string                               `json:"description"`
-	Features      AppFeatureSpec                       `json:"features"`
-	Icon          string                               `json:"icon"`
-	Name          string                               `json:"name"`
-	Repository    string                               `json:"repository"`
-	Versions      map[string]map[string]AppVersionSpec `json:"versions"`
-	Website       string                               `json:"website"`
+type App struct {
+	Category      string                        `json:"category"`
+	DefaultBranch string                        `json:"default_branch"`
+	Description   string                        `json:"description"`
+	Features      Feature                       `json:"features"`
+	Icon          string                        `json:"icon"`
+	Name          string                        `json:"name"`
+	Repository    string                        `json:"repository"`
+	Versions      map[string]map[string]Version `json:"versions"`
+	Website       string                        `json:"website"`
 }
 
-type AppsJson map[string]AppSpec
+type Apps map[string]App
 
-func getJson(url string, target interface{}) error {
-	client := &http.Client{Timeout: 5 * time.Second}
-	res, err := client.Get(url)
+var httpClient = &http.Client{Timeout: 5 * time.Second}
+
+var AppsUrl = "https://apps.coopcloud.tech"
+
+func readJson(url string, target interface{}) error {
+	res, err := httpClient.Get(url)
 	if err != nil {
 		return err
 	}
@@ -57,16 +64,80 @@ func getJson(url string, target interface{}) error {
 	return json.NewDecoder(res.Body).Decode(target)
 }
 
-func GetAppsJSON() (AppsJson, error) {
-	url := "https://apps.coopcloud.tech"
-	apps := make(AppsJson)
-	if err := getJson(url, &apps); err != nil {
+func AppsFSIsLatest() (bool, error) {
+	res, err := httpClient.Head(AppsUrl)
+	if err != nil {
+		return false, err
+	}
+
+	lastModified := res.Header["Last-Modified"][0]
+	parsed, err := time.Parse(time.RFC1123, lastModified)
+	if err != nil {
+		return false, err
+	}
+
+	info, err := os.Stat(config.APPS_JSON)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return false, nil
+		}
+		return false, err
+	}
+
+	localModifiedTime := info.ModTime().Unix()
+	remoteModifiedTime := parsed.Unix()
+
+	if localModifiedTime < remoteModifiedTime {
+		return false, nil
+	}
+
+	return true, nil
+}
+
+func ReadAppsFS(target interface{}) error {
+	appsJsonFS, err := ioutil.ReadFile(config.APPS_JSON)
+	if err != nil {
+		return err
+	}
+	if err := json.Unmarshal(appsJsonFS, &target); err != nil {
+		return err
+	}
+	return nil
+}
+
+func ReadAppsWeb() (Apps, error) {
+	apps := make(Apps)
+
+	appsFSIsLatest, err := AppsFSIsLatest()
+	if err != nil {
 		return nil, err
 	}
+
+	if !appsFSIsLatest {
+		if err := readJson(AppsUrl, &apps); err != nil {
+			return nil, err
+		}
+
+		appsJson, err := json.MarshalIndent(apps, "", "    ")
+		if err != nil {
+			return nil, err
+		}
+
+		if err := ioutil.WriteFile(config.APPS_JSON, appsJson, 0644); err != nil {
+			return nil, err
+		}
+
+		return apps, nil
+	}
+
+	if err := ReadAppsFS(&apps); err != nil {
+		return nil, err
+	}
+
 	return apps, nil
 }
 
-func sortByAppName(apps AppsJson) []string {
+func SortByAppName(apps Apps) []string {
 	var names []string
 	for name := range apps {
 		names = append(names, name)
@@ -79,15 +150,16 @@ var recipeListCommand = &cli.Command{
 	Name:    "list",
 	Aliases: []string{"ls"},
 	Action: func(c *cli.Context) error {
-		apps, err := GetAppsJSON()
+		appSpecs, err := ReadAppsWeb()
 		if err != nil {
 			logrus.Fatal(err.Error())
 		}
 		tableCol := []string{"Name", "Category", "Status"}
 		table := createTable(tableCol)
-		for _, name := range sortByAppName(apps) {
-			appSpec := apps[name]
-			tableRow := []string{appSpec.Name, appSpec.Category, fmt.Sprintf("%v", appSpec.Features.Status)}
+		for _, appName := range SortByAppName(appSpecs) {
+			appSpec := appSpecs[appName]
+			status := fmt.Sprintf("%v", appSpec.Features.Status)
+			tableRow := []string{appSpec.Name, appSpec.Category, status}
 			table.Append(tableRow)
 		}
 		table.Render()

config/env.go

@@ -16,6 +16,7 @@ import (
 
 var ABRA_DIR = os.ExpandEnv("$HOME/.abra")
 var ABRA_SERVER_FOLDER = path.Join(ABRA_DIR, "servers")
+var APPS_JSON = path.Join(ABRA_DIR, "apps.json")
 
 // Type aliases to make code hints easier to understand
 type AppEnv = map[string]string