Allow remote caching of docker layers in kaniko build

.drone.yml

@@ -58,4 +58,58 @@ steps:
   when:
     event:
       exclude:
-      - pull_request
+      - pull_request
+
+---
+kind: pipeline
+type: docker
+name: notifications-docker
+
+platform:
+  os: linux
+  arch: amd64
+
+steps:
+- name: manifest-docker
+  pull: always
+  image: plugins/manifest
+  settings:
+    auto_tag: true
+    ignore_missing: true
+    password:
+      from_secret: docker_password
+    spec: docker/docker/manifest.tmpl
+    username:
+      from_secret: docker_username
+
+- name: manifest-gcr
+  pull: always
+  image: plugins/manifest
+  settings:
+    auto_tag: true
+    ignore_missing: true
+    password:
+      from_secret: docker_password
+    spec: docker/gcr/manifest.tmpl
+    username:
+      from_secret: docker_username
+
+- name: manifest-ecr
+  pull: always
+  image: plugins/manifest
+  settings:
+    auto_tag: true
+    ignore_missing: true
+    password:
+      from_secret: docker_password
+    spec: docker/ecr/manifest.tmpl
+    username:
+      from_secret: docker_username
+
+trigger:
+  ref:
+  - refs/heads/main
+  - "refs/tags/**"
+
+depends_on:
+- default

cmd/kaniko-docker/main.go

@@ -104,6 +104,21 @@ func main() {
 			Usage:  "Specify one of full, redo or time as snapshot mode",
 			EnvVar: "PLUGIN_SNAPSHOT_MODE",
 		},
+		cli.BoolFlag{
+			Name:   "enable-cache",
+			Usage:  "Set this flag to opt into caching with kaniko",
+			EnvVar: "PLUGIN_ENABLE_CACHE",
+		},
+		cli.StringFlag{
+			Name:   "cache-repo",
+			Usage:  "Remote repository that will be used to store cached layers. enable-cache needs to be set to use this flag",
+			EnvVar: "PLUGIN_CACHE_REPO",
+		},
+		cli.IntFlag{
+			Name:   "cache-ttl",
+			Usage:  "Cache timeout in hours. Defaults to two weeks.",
+			EnvVar: "PLUGIN_CACHE_TTL",
+		},
 	}
 
 	if err := app.Run(os.Args); err != nil {

cmd/kaniko-ecr/main.go

@@ -94,6 +94,21 @@ func main() {
 			Usage:  "Specify one of full, redo or time as snapshot mode",
 			EnvVar: "PLUGIN_SNAPSHOT_MODE",
 		},
+		cli.BoolFlag{
+			Name:   "enable-cache",
+			Usage:  "Set this flag to opt into caching with kaniko",
+			EnvVar: "PLUGIN_ENABLE_CACHE",
+		},
+		cli.StringFlag{
+			Name:   "cache-repo",
+			Usage:  "Remote repository that will be used to store cached layers. enable-cache needs to be set to use this flag",
+			EnvVar: "PLUGIN_CACHE_REPO",
+		},
+		cli.IntFlag{
+			Name:   "cache-ttl",
+			Usage:  "Cache timeout in hours. Defaults to two weeks.",
+			EnvVar: "PLUGIN_CACHE_TTL",
+		},
 	}
 
 	if err := app.Run(os.Args); err != nil {

cmd/kaniko-gcr/main.go

@@ -90,6 +90,21 @@ func main() {
 			Usage:  "Specify one of full, redo or time as snapshot mode",
 			EnvVar: "PLUGIN_SNAPSHOT_MODE",
 		},
+		cli.BoolFlag{
+			Name:   "enable-cache",
+			Usage:  "Set this flag to opt into caching with kaniko",
+			EnvVar: "PLUGIN_ENABLE_CACHE",
+		},
+		cli.StringFlag{
+			Name:   "cache-repo",
+			Usage:  "Remote repository that will be used to store cached layers. enable-cache needs to be set to use this flag",
+			EnvVar: "PLUGIN_CACHE_REPO",
+		},
+		cli.IntFlag{
+			Name:   "cache-ttl",
+			Usage:  "Cache timeout in hours. Defaults to two weeks.",
+			EnvVar: "PLUGIN_CACHE_TTL",
+		},
 	}
 
 	if err := app.Run(os.Args); err != nil {

kaniko.go

@@ -19,6 +19,9 @@ type (
 		Labels        []string // Label map
 		SkipTlsVerify bool     // Docker skip tls certificate verify for registry
 		SnapshotMode  string   // Kaniko snapshot mode
+		EnableCache   bool     // Whether to enable kaniko cache
+		CacheRepo     string   // Remote repository that will be used to store cached layers
+		CacheTTL      int      // Cache timeout in hours
 	}
 
 	// Plugin defines the Docker plugin parameters.
@@ -67,6 +70,18 @@ func (p Plugin) Exec() error {
 		cmdArgs = append(cmdArgs, fmt.Sprintf("--snapshotMode=%s", p.Build.SnapshotMode))
 	}
 
+	if p.Build.EnableCache == true {
+		cmdArgs = append(cmdArgs, fmt.Sprintf("--cache=true"))
+	}
+
+	if p.Build.CacheRepo != "" {
+		cmdArgs = append(cmdArgs, fmt.Sprintf("--cache-repo=%s", p.Build.CacheRepo))
+	}
+
+	if p.Build.CacheTTL != 0 {
+		cmdArgs = append(cmdArgs, fmt.Sprintf("--cache-ttl=%d", p.Build.CacheTTL))
+	}
+
 	cmd := exec.Command("/kaniko/executor", cmdArgs...)
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr