Ensure flux bin is on path

pkg/flux/flux.go

@@ -1,16 +1,18 @@
 package flux
 
 import (
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"os"
+	"os/exec"
 
 	"github.com/kris-nova/logger"
 	api "github.com/weaveworks/eksctl/pkg/apis/eksctl.io/v1alpha5"
 	"github.com/weaveworks/eksctl/pkg/executor"
 )
 
-const fluxCommand = "flux"
+const fluxBin = "flux"
 
 type Client struct {
 	Executor executor.Executor
@@ -57,6 +59,11 @@ func setEnvVars(tokenPath, gitProvider string) []string {
 }
 
 func (c *Client) PreFlight() error {
+	if _, err := exec.LookPath(fluxBin); err != nil {
+		logger.Warning(err.Error())
+		return errors.New("flux not found, required")
+	}
+
 	return c.runFluxCmd("check", "--pre")
 }
 
@@ -81,5 +88,5 @@ func (c *Client) Bootstrap(opts *api.Toolkit) error {
 
 func (c *Client) runFluxCmd(args ...string) error {
 	logger.Debug(fmt.Sprintf("running flux %v ", args))
-	return c.Executor.Exec(fluxCommand, args...)
+	return c.Executor.Exec(fluxBin, args...)
 }

pkg/flux/flux_test.go

@@ -2,6 +2,7 @@ package flux_test
 
 import (
 	"errors"
+	"os"
 
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
@@ -29,7 +30,24 @@ var _ = Describe("Flux", func() {
 			Expect(receivedArgs).To(Equal([]string{"check", "--pre"}))
 		})
 
-		Context("when execution fails", func() {
+		When("the flux binary is not found on the path", func() {
+			var pathEnv string
+
+			BeforeEach(func() {
+				pathEnv = os.Getenv("PATH")
+				Expect(os.Unsetenv("PATH")).To(Succeed())
+			})
+
+			AfterEach(func() {
+				Expect(os.Setenv("PATH", pathEnv)).To(Succeed())
+			})
+
+			It("returns the error", func() {
+				Expect(fluxClient.PreFlight()).To(MatchError("flux not found, required"))
+			})
+		})
+
+		When("execution fails", func() {
 			BeforeEach(func() {
 				fakeExecutor.ExecReturns(errors.New("omg"))
 			})