From c734efefcec713d28724036039b492585c1f4c93 Mon Sep 17 00:00:00 2001
From: Will Price <will.price@oracle.com>
Date: Thu, 20 Jul 2017 09:54:14 -0700
Subject: [PATCH] Teach `fn build` `--no-cache` to avoid using cached steps

---
 fn/build.go  |  8 +++++++-
 fn/common.go | 16 +++++++++++-----
 fn/deploy.go |  8 +++++++-
 3 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/fn/build.go b/fn/build.go
index 733b84757..2c4512ad4 100644
--- a/fn/build.go
+++ b/fn/build.go
@@ -20,6 +20,7 @@ func build() cli.Command {
 
 type buildcmd struct {
 	verbose bool
+	noCache bool
 }
 
 func (b *buildcmd) flags() []cli.Flag {
@@ -29,6 +30,11 @@ func (b *buildcmd) flags() []cli.Flag {
 			Usage:       "verbose mode",
 			Destination: &b.verbose,
 		},
+		cli.BoolFlag{
+			Name:        "no-cache",
+			Usage:       "Don't use docker cache",
+			Destination: &b.noCache,
+		},
 	}
 }
 
@@ -45,7 +51,7 @@ func (b *buildcmd) build(c *cli.Context) error {
 		return err
 	}
 
-	ff, err := buildfunc(verbwriter, fn)
+	ff, err := buildfunc(verbwriter, fn, b.noCache)
 	if err != nil {
 		return err
 	}
diff --git a/fn/common.go b/fn/common.go
index 804933fd2..544360d6d 100644
--- a/fn/common.go
+++ b/fn/common.go
@@ -33,7 +33,7 @@ func verbwriter(verbose bool) io.Writer {
 	return verbwriter
 }
 
-func buildfunc(verbwriter io.Writer, fn string) (*funcfile, error) {
+func buildfunc(verbwriter io.Writer, fn string, noCache bool) (*funcfile, error) {
 	funcfile, err := parsefuncfile(fn)
 	if err != nil {
 		return nil, err
@@ -57,7 +57,7 @@ func buildfunc(verbwriter io.Writer, fn string) (*funcfile, error) {
 		return nil, err
 	}
 
-	if err := dockerbuild(verbwriter, fn, funcfile); err != nil {
+	if err := dockerbuild(verbwriter, fn, funcfile, noCache); err != nil {
 		return nil, err
 	}
 
@@ -78,7 +78,7 @@ func localbuild(verbwriter io.Writer, path string, steps []string) error {
 	return nil
 }
 
-func dockerbuild(verbwriter io.Writer, path string, ff *funcfile) error {
+func dockerbuild(verbwriter io.Writer, path string, ff *funcfile, noCache bool) error {
 	err := dockerVersionCheck()
 	if err != nil {
 		return err
@@ -115,13 +115,19 @@ func dockerbuild(verbwriter io.Writer, path string, ff *funcfile) error {
 	result := make(chan error, 1)
 
 	go func(done chan<- error) {
-		cmd := exec.Command("docker", "build",
+		args := []string{
+			"build",
 			"-t", ff.FullName(),
 			"-f", dockerfile,
-			// "--no-cache",
+		}
+		if noCache {
+			args = append(args, "--no-cache")
+		}
+		args = append(args,
 			"--build-arg", "HTTP_PROXY",
 			"--build-arg", "HTTPS_PROXY",
 			".")
+		cmd := exec.Command("docker", args...)
 		cmd.Dir = dir
 		cmd.Stderr = os.Stderr
 		cmd.Stdout = os.Stdout
diff --git a/fn/deploy.go b/fn/deploy.go
index 2d4dae7a4..12007daba 100644
--- a/fn/deploy.go
+++ b/fn/deploy.go
@@ -39,6 +39,7 @@ type deploycmd struct {
 	verbose     bool
 	incremental bool
 	skippush    bool
+	noCache     bool
 
 	verbwriter io.Writer
 }
@@ -62,6 +63,11 @@ func (p *deploycmd) flags() []cli.Flag {
 			Usage:       "uses incremental building",
 			Destination: &p.incremental,
 		},
+		cli.BoolFlag{
+			Name:        "no-cache",
+			Usage:       "Don't use Docker cache for the build",
+			Destination: &p.noCache,
+		},
 		cli.BoolFlag{
 			Name:        "skip-push",
 			Usage:       "does not push Docker built images onto Docker Hub - useful for local development.",
@@ -126,7 +132,7 @@ func (p *deploycmd) deploy(c *cli.Context, funcFilePath string) error {
 		return err
 	}
 
-	funcfile, err := buildfunc(p.verbwriter, funcFileName)
+	funcfile, err := buildfunc(p.verbwriter, funcFileName, p.noCache)
 	if err != nil {
 		return err
 	}