From 008bbaf47bf51feba943cee006c49cf27269913a Mon Sep 17 00:00:00 2001
From: Seth Pollack <seth@sethpollack.net>
Date: Thu, 26 Oct 2017 12:26:26 -0400
Subject: [PATCH] make cache-from an array

---
 cmd/drone-docker/main.go |  3 ++-
 docker.go                | 10 +++++-----
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/cmd/drone-docker/main.go b/cmd/drone-docker/main.go
index 36ad2f9..7028cf8 100644
--- a/cmd/drone-docker/main.go
+++ b/cmd/drone-docker/main.go
@@ -150,6 +150,7 @@ func main() {
 			Name:   "target",
 			Usage:  "build target",
 			EnvVar: "PLUGIN_TARGET",
+		},
 		cli.StringSliceFlag{
 			Name:   "cache-from",
 			Usage:  "cache from",
@@ -249,7 +250,7 @@ func run(c *cli.Context) error {
 			Target:      c.String("target"),
 			Squash:      c.Bool("squash"),
 			Pull:        c.BoolT("pull-image"),
-			CacheFrom:   c.String("cache-from"),
+			CacheFrom:   c.StringSlice("cache-from"),
 			Compress:    c.Bool("compress"),
 			Repo:        c.String("repo"),
 			Labels:      c.StringSlice("custom-labels"),
diff --git a/docker.go b/docker.go
index 03e1105..0a3cfa5 100644
--- a/docker.go
+++ b/docker.go
@@ -47,7 +47,7 @@ type (
 		Target      string   // Docker build target
 		Squash      bool     // Docker build squash
 		Pull        bool     // Docker build pull
-		CacheFrom   string   // Docker build cache-from
+		CacheFrom   []string // Docker build cache-from
 		Compress    bool     // Docker build compress
 		Repo        string   // Docker build repository
 		LabelSchema []string // label-schema Label map
@@ -106,8 +106,8 @@ func (p Plugin) Exec() error {
 	}
 
 	// pre-pull cache image
-	if p.Build.CacheFrom != "" {
-		cmd := commandPull(p.Build.CacheFrom)
+	for _, img := range p.Build.CacheFrom {
+		cmd := commandPull(img)
 		cmd.Stdout = os.Stdout
 		cmd.Stderr = os.Stderr
 		trace(cmd)
@@ -218,8 +218,8 @@ func commandBuild(build Build) *exec.Cmd {
 	if build.NoCache {
 		args = append(args, "--no-cache")
 	}
-	if build.CacheFrom != "" {
-		args = append(args, "--cache-from", build.CacheFrom)
+	for _, arg := range build.CacheFrom {
+		args = append(args, "--cache-from", arg)
 	}
 	for _, arg := range build.ArgsEnv {
 		addProxyValue(&build, arg)