Add knife config by template

Since the chef-client provisioner is cleaning the node and client at the chef-server from the provisioned node
it needs to have a flexible configuration

This is replacing the used knife flags: -s '<chef-server-url>' -k '/tmp/packer-chef-client/client.pem' -u '<client-name>'
and puts their values into a generated knife.rb

Additionally the knife.rb may include the optional ssl_verify_mode attribute to enable the verify mode verify_none

Background:

When deleting node and client to a self-hosted chef-server using self signed cerfiticates the usage of

    knife node delete <node-name> -y -s '<chef-server-url>' -k '/tmp/packer-chef-client/client.pem' -u '<client-name>'

will lead into a ssl verification failure.

The error output of the knife call is somthing like:

    2015/06/24 12:29:17 ui:     docker: WARNING: No knife configuration file found
    docker: WARNING: No knife configuration file found
    2015/06/24 12:29:17 ui:     docker: ERROR: SSL Validation failure connecting to host: 172.16.117.63 - SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B:
    certificate verify failed
    docker: ERROR: SSL Validation failure connecting to host: 172.16.117.63 - SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed
    2015/06/24 12:29:17 ui:     docker: ERROR: Could not establish a secure connection to the server.
    docker: ERROR: Could not establish a secure connection to the server.
    2015/06/24 12:29:17 ui:     docker: Use 'knife ssl check' to troubleshoot your SSL configuration.
    docker: Use 'knife ssl check' to troubleshoot your SSL configuration.
    2015/06/24 12:29:17 ui:     docker: If your Chef Server uses a self-signed certificate, you can use
    docker: If your Chef Server uses a self-signed certificate, you can use
    2015/06/24 12:29:17 ui:     docker: 'knife ssl fetch' to make knife trust the server's certificates.
    docker: 'knife ssl fetch' to make knife trust the server's certificates.
    2015/06/24 12:29:17 ui:     docker:
    docker:
    2015/06/24 12:29:17 ui:     docker: Original Exception: OpenSSL::SSL::SSLError: SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed
    docker: Original Exception: OpenSSL::SSL::SSLError: SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed
    2015/06/24 12:29:17 packer-builder-docker: 2015/06/24 12:29:17 Executed command exit status: 100

provisioner/chef-client/provisioner.go

@@ -187,14 +187,20 @@ func (p *Provisioner) Provision(ui packer.Ui, comm packer.Communicator) error {
 	}
 
 	err = p.executeChef(ui, comm, configPath, jsonPath)
+
+	knifeConfigPath, err2 := p.createKnifeConfig(
+		ui, comm, nodeName, serverUrl, p.config.ClientKey, p.config.SslVerifyMode)
+	if err2 != nil {
+		return fmt.Errorf("Error creating knife config on node: %s", err2)
+	}
 	if !p.config.SkipCleanNode {
-		if err2 := p.cleanNode(ui, comm, nodeName); err2 != nil {
+		if err2 := p.cleanNode(ui, comm, nodeName, knifeConfigPath); err2 != nil {
 			return fmt.Errorf("Error cleaning up chef node: %s", err2)
 		}
 	}
 
 	if !p.config.SkipCleanClient {
-		if err2 := p.cleanClient(ui, comm, nodeName); err2 != nil {
+		if err2 := p.cleanClient(ui, comm, nodeName, knifeConfigPath); err2 != nil {
 			return fmt.Errorf("Error cleaning up chef client: %s", err2)
 		}
 	}
@@ -273,6 +279,32 @@ func (p *Provisioner) createConfig(ui packer.Ui, comm packer.Communicator, nodeN
 	return remotePath, nil
 }
 
+func (p *Provisioner) createKnifeConfig(ui packer.Ui, comm packer.Communicator, nodeName string, serverUrl string, clientKey string, sslVerifyMode string) (string, error) {
+	ui.Message("Creating configuration file 'knife.rb'")
+
+	// Read the template
+	tpl := DefaultKnifeTemplate
+
+	ctx := p.config.ctx
+	ctx.Data = &ConfigTemplate{
+		NodeName:             nodeName,
+		ServerUrl:            serverUrl,
+		ClientKey:            clientKey,
+		SslVerifyMode:        sslVerifyMode,
+	}
+	configString, err := interpolate.Render(tpl, &ctx)
+	if err != nil {
+		return "", err
+	}
+
+	remotePath := filepath.ToSlash(filepath.Join(p.config.StagingDir, "knife.rb"))
+	if err := comm.Upload(remotePath, bytes.NewReader([]byte(configString)), nil); err != nil {
+		return "", err
+	}
+
+	return remotePath, nil
+}
+
 func (p *Provisioner) createJson(ui packer.Ui, comm packer.Communicator) (string, error) {
 	ui.Message("Creating JSON attribute file")
 
@@ -334,32 +366,30 @@ func (p *Provisioner) createDir(ui packer.Ui, comm packer.Communicator, dir stri
 	return nil
 }
 
-func (p *Provisioner) cleanNode(ui packer.Ui, comm packer.Communicator, node string) error {
+func (p *Provisioner) cleanNode(ui packer.Ui, comm packer.Communicator, node string, knifeConfigPath string) error {
 	ui.Say("Cleaning up chef node...")
 	args := []string{"node", "delete", node}
-	if err := p.knifeExec(ui, comm, node, args); err != nil {
+	if err := p.knifeExec(ui, comm, node, knifeConfigPath, args); err != nil {
 		return fmt.Errorf("Failed to cleanup node: %s", err)
 	}
 
 	return nil
 }
 
-func (p *Provisioner) cleanClient(ui packer.Ui, comm packer.Communicator, node string) error {
+func (p *Provisioner) cleanClient(ui packer.Ui, comm packer.Communicator, node string, knifeConfigPath string) error {
 	ui.Say("Cleaning up chef client...")
 	args := []string{"client", "delete", node}
-	if err := p.knifeExec(ui, comm, node, args); err != nil {
+	if err := p.knifeExec(ui, comm, node, knifeConfigPath, args); err != nil {
 		return fmt.Errorf("Failed to cleanup client: %s", err)
 	}
 
 	return nil
 }
 
-func (p *Provisioner) knifeExec(ui packer.Ui, comm packer.Communicator, node string, args []string) error {
+func (p *Provisioner) knifeExec(ui packer.Ui, comm packer.Communicator, node string, knifeConfigPath string, args []string) error {
 	flags := []string{
 		"-y",
-		"-s", fmt.Sprintf("'%s'", p.config.ServerUrl),
-		"-k", fmt.Sprintf("'%s'", p.config.ClientKey),
-		"-u", fmt.Sprintf("'%s'", node),
+		"-c", knifeConfigPath,
 	}
 
 	cmdText := fmt.Sprintf(
@@ -573,3 +603,14 @@ environment "{{.ChefEnvironment}}"
 ssl_verify_mode :{{.SslVerifyMode}}
 {{end}}
 `
+
+var DefaultKnifeTemplate = `
+log_level        :info
+log_location     STDOUT
+chef_server_url  "{{.ServerUrl}}"
+client_key       "{{.ClientKey}}"
+node_name "{{.NodeName}}"
+{{if ne .SslVerifyMode ""}}
+ssl_verify_mode :{{.SslVerifyMode}}
+{{end}}
+`