if ssh_key_id is specified don't import ssh public key

[pragnesh]

if ssh_key_id is specified , add a check to not import private key

fixes #113

[andrewsomething]

@pragnesh Thanks for flagging this issue for us and opening this PR!

This change does resolve the problem, but I think there might be a better approach. Here we skip uploading the temporary key pair to DigitalOcean if a key ID is passed, but we're still actually generating the temporary key pair locally. it just never gets used. How about moving the conditional to builder/digitalocean/builder.go to prevent generating the key pair altogether when it's not needed?

Something like:

diff --git a/builder/digitalocean/builder.go b/builder/digitalocean/builder.go
index 899dee4..0532410 100644
--- a/builder/digitalocean/builder.go
+++ b/builder/digitalocean/builder.go
@@ -102,19 +102,24 @@ func (b *Builder) Run(ctx context.Context, ui packersdk.Ui, hook packersdk.Hook)
 	state.Put("hook", hook)
 	state.Put("ui", ui)
 
+	// Only generate the temp key pair if one is not already provided
+	genTempKeyPair := b.config.SSHKeyID == 0 || b.config.Comm.SSHPrivateKeyFile == ""
+
 	// Build the steps
 	steps := []multistep.Step{
-		&communicator.StepSSHKeyGen{
-			CommConf:            &b.config.Comm,
-			SSHTemporaryKeyPair: b.config.Comm.SSH.SSHTemporaryKeyPair,
-		},
+		multistep.If(genTempKeyPair,
+			&communicator.StepSSHKeyGen{
+				CommConf:            &b.config.Comm,
+				SSHTemporaryKeyPair: b.config.Comm.SSH.SSHTemporaryKeyPair,
+			},
+		),
 		multistep.If(b.config.PackerDebug && b.config.Comm.SSHPrivateKeyFile == "",
 			&communicator.StepDumpSSHKey{
 				Path: fmt.Sprintf("do_%s.pem", b.config.PackerBuildName),
 				SSH:  &b.config.Comm.SSH,
 			},
 		),
-		&stepCreateSSHKey{},
+		multistep.If(genTempKeyPair, new(stepCreateSSHKey)),
 		new(stepCreateDroplet),
 		new(stepDropletInfo),
 		&communicator.StepConnect{
@@ -123,9 +128,11 @@ func (b *Builder) Run(ctx context.Context, ui packersdk.Ui, hook packersdk.Hook)
 			SSHConfig: b.config.Comm.SSHConfigFunc(),
 		},
 		new(commonsteps.StepProvision),
-		&commonsteps.StepCleanupTempKeys{
-			Comm: &b.config.Comm,
-		},
+		multistep.If(genTempKeyPair,
+			&commonsteps.StepCleanupTempKeys{
+				Comm: &b.config.Comm,
+			},
+		),
 		new(stepShutdown),
 		new(stepPowerOff),
 		&stepSnapshot{

[pragnesh]

@andrewsomething yes that is better approach, do you want me to update pull request ?

I have updated pull requested as you have suggested and tested locally, it looks good to me.

Thanks for review.

[andrewsomething]

👍

Thanks again!