Add support to use user data when launching instance (#33)

Hi team! In this PR, I added support for using User-Data to
automatically provision instances. It is possible to pass it directly or
using the script/cloud-init file.

builder/exoscale/builder_test.go

@@ -1,6 +1,7 @@
 package exoscale
 
 import (
+	"encoding/base64"
 	"math/rand"
 	"net"
 	"os"
@@ -34,6 +35,9 @@ var (
 	testTemplateID                 = new(testSuite).randomID()
 	testTemplateName               = "packer-plugin-test-" + new(testSuite).randomString(6)
 	testTemplateZones              = []string{"ch-gva-2", "ch-dk-2"}
+	testUserData                   = "echo test > /etc/test.txt"
+	testUserDataBase64             = base64.StdEncoding.EncodeToString([]byte(testUserData))
+	testUserDataFile               = "userdata.txt"
 
 	testSeededRand = rand.New(rand.NewSource(time.Now().UnixNano()))
 )

builder/exoscale/config.go

@@ -4,6 +4,7 @@ package exoscale
 
 import (
 	"fmt"
+	"os"
 	"reflect"
 
 	"github.com/hashicorp/hcl/v2/hcldec"
@@ -50,6 +51,8 @@ type Config struct {
 	TemplateMaintainer         string   `mapstructure:"template_maintainer"`
 	TemplateVersion            string   `mapstructure:"template_version"`
 	TemplateBuild              string   `mapstructure:"template_build"`
+	UserData                   string   `mapstructure:"user_data"`
+	UserDataFile               string   `mapstructure:"user_data_file"`
 	// Deprecated
 	TemplateZone string `mapstructure:"template_zone"`
 
@@ -102,6 +105,14 @@ func NewConfig(raws ...interface{}) (*Config, []string, error) {
 		}
 	}
 
+	if config.UserData != "" && config.UserDataFile != "" {
+		errs = packer.MultiErrorAppend(errs, fmt.Errorf("Only one of user_data or user_data_file can be specified."))
+	} else if config.UserDataFile != "" {
+		if _, err := os.Stat(config.UserDataFile); err != nil {
+			errs = packer.MultiErrorAppend(errs, fmt.Errorf("user_data_file not found: %s", config.UserDataFile))
+		}
+	}
+
 	if es := config.Comm.Prepare(&config.ctx); len(es) > 0 {
 		errs = packer.MultiErrorAppend(errs, es...)
 	}

builder/exoscale/config_test.go

@@ -1,5 +1,7 @@
 package exoscale
 
+import "os"
+
 var (
 	testConfigAPIKey               = "EXOabcdef0123456789abcdef01"
 	testConfigAPISecret            = "ABCDEFGHIJKLMNOPRQSTUVWXYZ0123456789abcdefg"
@@ -9,6 +11,8 @@ var (
 	testConfigTemplateZones        = []string{"ch-gva-2", "ch-dk-2"}
 	testConfigTemplateName         = "test-packer"
 	testConfigSSHUsername          = "ubuntu"
+	testConfigUserData             = "sed -i -E 's/#?PasswordAuthentication yes/PasswordAuthentication no/' /etc/ssh/sshd_config"
+	testConfigUserDataFile         = "disable_ssh_password_auth.sh"
 	// Deprecated
 	testConfigTemplateZone = "ch-dk-2"
 )
@@ -27,6 +31,7 @@ func (ts *testSuite) TestNewConfig() {
 		"template_name":          testConfigTemplateName,
 		"template_zones":         testConfigTemplateZones,
 		"ssh_username":           testConfigSSHUsername,
+		"user_data":              testConfigUserData,
 	}}...)
 	ts.Require().NoError(err)
 	ts.Require().NotNil(config)
@@ -39,6 +44,38 @@ func (ts *testSuite) TestNewConfig() {
 	ts.Require().Equal(testConfigSnapshotDownloadPath, config.SnapshotDownloadPath)
 	ts.Require().Equal(testConfigTemplateZones[0], config.InstanceZone)
 	ts.Require().Equal(defaultTemplateBootMode, config.TemplateBootMode)
+	ts.Require().Equal(testConfigUserData, config.UserData)
+
+	_, _, err = NewConfig([]interface{}{map[string]interface{}{
+		// Minimal configuration
+		"api_key":           testConfigAPIKey,
+		"api_secret":        testConfigAPISecret,
+		"instance_template": testConfigInstanceTemplate,
+		"template_name":     testConfigTemplateName,
+		"template_zones":    testConfigTemplateZones,
+		"ssh_username":      testConfigSSHUsername,
+		"user_data":         testConfigUserData,
+		"user_data_file":    testConfigUserDataFile,
+	}}...)
+	ts.Require().ErrorContains(err, "Only one of user_data or user_data_file can be specified.")
+
+	tmpFile, err := os.CreateTemp(os.TempDir(), testConfigUserDataFile)
+	ts.Require().NoError(err, "unable to create temporary file")
+	ts.Require().NoError(tmpFile.Close())
+	ts.Require().FileExists(tmpFile.Name())
+
+	config, _, err = NewConfig([]interface{}{map[string]interface{}{
+		// Minimal configuration
+		"api_key":           testConfigAPIKey,
+		"api_secret":        testConfigAPISecret,
+		"instance_template": testConfigInstanceTemplate,
+		"template_name":     testConfigTemplateName,
+		"template_zones":    testConfigTemplateZones,
+		"ssh_username":      testConfigSSHUsername,
+		"user_data_file":    tmpFile.Name(),
+	}}...)
+	ts.Require().NoError(err)
+	ts.Require().Equal(tmpFile.Name(), config.UserDataFile)
 }
 
 func (ts *testSuite) TestNewConfigDeprecated() {

builder/exoscale/step_create_instance.go

@@ -2,7 +2,9 @@ package exoscale
 
 import (
 	"context"
+	"encoding/base64"
 	"fmt"
+	"os"
 
 	egoscale "github.com/exoscale/egoscale/v2"
 	exoapi "github.com/exoscale/egoscale/v2/api"
@@ -104,6 +106,26 @@ func (s *stepCreateInstance) Run(ctx context.Context, state multistep.StateBag)
 		instance.SecurityGroupIDs = &securityGroupIDs
 	}
 
+	userData := s.builder.config.UserData
+	if s.builder.config.UserDataFile != "" {
+		contents, err := os.ReadFile(s.builder.config.UserDataFile)
+		if err != nil {
+			ui.Error(fmt.Sprintf("Unable to read user data file: %v", err))
+			return multistep.ActionHalt
+		}
+
+		userData = string(contents)
+	}
+
+	if userData != "" {
+		// Test if it is encoded already, and if not, encode it
+		if _, err := base64.StdEncoding.DecodeString(userData); err != nil {
+			userData = base64.StdEncoding.EncodeToString([]byte(userData))
+		}
+
+		instance.UserData = &userData
+	}
+
 	instance, err = s.builder.exo.CreateInstance(ctx, s.builder.config.InstanceZone, instance)
 	if err != nil {
 		ui.Error(fmt.Sprintf("Unable to create compute instance: %v", err))

builder/exoscale/step_create_instance_test.go

@@ -2,6 +2,7 @@ package exoscale
 
 import (
 	"context"
+	"os"
 
 	"github.com/hashicorp/packer-plugin-sdk/multistep"
 	"github.com/hashicorp/packer-plugin-sdk/packer"
@@ -28,6 +29,14 @@ func (ts *testSuite) TestStepCreateInstance_Run() {
 		instancePrivateNetworkAttached bool
 	)
 
+	tmpUserDataFile, err := os.CreateTemp(os.TempDir(), testUserDataFile)
+	ts.Require().NoError(err, "unable to create temporary userdata file")
+	ts.Require().FileExists(tmpUserDataFile.Name())
+	_, err = tmpUserDataFile.WriteString(testUserData)
+	ts.Require().NoError(err)
+	ts.Require().NoError(tmpUserDataFile.Close())
+	testConfig.UserDataFile = tmpUserDataFile.Name()
+
 	testInstance := &egoscale.Instance{
 		ID:              &testInstanceID,
 		Name:            &testInstanceName,
@@ -99,6 +108,7 @@ func (ts *testSuite) TestStepCreateInstance_Run() {
 					SSHKey:           &testConfig.InstanceSSHKey,
 					SecurityGroupIDs: &[]string{testInstanceSecurityGroupID},
 					TemplateID:       &testTemplateID,
+					UserData:         &testUserDataBase64,
 				},
 				args.Get(2))
 			instanceCreated = true

docs/builders/exoscale.md

@@ -83,6 +83,13 @@ other OS, we recommend using the [QEMU][packerqemu] plugin combined with the
 - `template_disable_sshkey` (boolean) - Whether the template should disable
   SSH key installation during Compute instance creation. Defaults to `false`.
 
+- `user_data` (string) - User data to apply when launching the instance. Note
+  that you need to be careful about escaping characters due to the templates
+  being JSON. See [documentation][cloudinit] to learn more about user data.
+
+- `user_data_file` (string) - The path to a file that will be used for the user
+  data when launching the instance.
+
 In addition to plugin-specific configuration parameters, you can also adjust
 the [SSH communicator][packerssh] settings to configure how Packer will log
 into the Compute instance.
@@ -119,3 +126,4 @@ build {
 [packerssh]: https://www.packer.io/docs/communicators/ssh/
 [zones]: https://www.exoscale.com/datacenters/
 [packerqemu]: https://www.packer.io/plugins/builders/qemu
+[cloudinit]: https://community.exoscale.com/documentation/compute/cloud-init/