fix(engine): reorganize packages

README.md

@@ -1,8 +1,6 @@
 # k3se 🧀
 
-A lightweight Kubernetes engine that deploys `k3s` clusters declaratively based on a cluster configuration file.
-
-The name is a hommage to the German word for cheese, _Käse [ˈkɛːzə]_.
+A lightweight Kubernetes engine that deploys `k3s` clusters declaratively based on a cluster configuration file. The name is a hommage to the German word for cheese, _Käse [ˈkɛːzə]_.
 
 ## License 📄
 

cmd/up.go

@@ -3,7 +3,7 @@ package cmd
 import (
 	"github.com/spf13/cobra"
 
-	"github.com/nicklasfrahm/k3se/pkg/k3se"
+	"github.com/nicklasfrahm/k3se/pkg/ops"
 )
 
 var upCmd = &cobra.Command{
@@ -19,10 +19,10 @@ argument.`,
 	RunE: func(cmd *cobra.Command, args []string) error {
 		// Use manual override for config path if provided.
 		if len(args) == 1 {
-			return k3se.Up(k3se.WithConfigPath(args[0]))
+			return ops.Up(ops.WithConfigPath(args[0]))
 		}
 
-		return k3se.Up()
+		return ops.Up()
 	},
 }
 

examples/standalone.yml

@@ -10,13 +10,13 @@ cluster:
     - kubeapi.example.com
   disable:
     - traefik
-  write-kubeconfig-mode: "0644"
+  write-kubeconfig-mode: "644"
 
 # A list of all nodes in the cluster and their connection information.
 nodes:
   - role: server
     ssh:
-      host: 192.168.254.254
+      host: 127.0.0.1
       fingerprint: SHA256:t/bwWCelgcAEYmQW9XbM4p31e1Qq70ZPWOKK+FRxBCc
       user: nicklasfrahm
       key-file: ~/.ssh/id_ed25519

pkg/k3se/config.go → pkg/engine/config.go

@@ -1,30 +1,25 @@
-package k3se
+package engine
 
 import (
 	"errors"
-	"fmt"
 	"io/ioutil"
 
-	"github.com/nicklasfrahm/k3se/pkg/rexec"
+	"github.com/nicklasfrahm/k3se/pkg/sshx"
 	"gopkg.in/yaml.v3"
 )
 
+// Role is the type of a node in the cluster.
+type Role string
+
 const (
+	// RoleAny is the role selector that matches any node.
+	RoleAny Role = "any"
 	// RoleServer is the role of a control-plane node in k3s.
-	RoleServer = "server"
+	RoleServer Role = "server"
 	// RoleAgent is the role of a worker node in k3s.
-	RoleAgent = "agent"
-	// Program is used to configure the name of the configuration file.
-	Program = "k3se"
+	RoleAgent Role = "agent"
 )
 
-// Node describes the configuration of a node.
-type Node struct {
-	Role      string          `yaml:"role"`
-	SSH       rexec.SSHConfig `yaml:"ssh"`
-	NodeLabel []string        `yaml:"node-label"`
-}
-
 // K3sConfig describes the configuration of a k3s node.
 type K3sConfig struct {
 	WriteKubeconfigMode string   `yaml:"write-kubeconfig-mode"`
@@ -40,67 +35,65 @@ type Config struct {
 	// channel as specified in the k3s installation options.
 	Version string `yaml:"version"`
 
-	// Config is the desired content of the k3s configuration file.
+	// Config is the desired content of the k3s configuration file
+	// that is shared among all nodes.
 	Cluster K3sConfig `yaml:"config"`
 
-	// Nodes is a list of nodes to deploy the cluster on.
+	// Nodes is a list of nodes to deploy the cluster on. It stores
+	// both, connection information and node-specific configuration.
 	Nodes []Node `yaml:"nodes"`
 
 	// SSHProxy describes the SSH connection configuration
 	// for an SSH proxy, often also referred to as bastion
 	// host or jumpbox.
-	SSHProxy rexec.SSHConfig `yaml:"ssh-proxy"`
+	SSHProxy sshx.Config `yaml:"ssh-proxy"`
 }
 
 // Verify verifies the configuration file.
+// TODO: How do we pass a logger to this function?
+// TODO: Use logger to display configuration errors.
 func (c *Config) Verify() error {
 	if c == nil {
 		return errors.New("configuration empty")
 	}
 
-	checks := []func() error{
-		c.VerifyServerCount,
+	if c.Nodes == nil || len(c.Nodes) == 0 {
+		return errors.New("no nodes specified")
 	}
 
-	var configInvalid bool
-	for _, check := range checks {
-		if err := check(); err != nil {
-			configInvalid = true
-
-			// TODO: Improve how errors are displayed and handled.
-			fmt.Println(err)
+	var controlPlanes = 0
+	for _, node := range c.Nodes {
+		if node.Role == RoleServer {
+			controlPlanes += 1
 		}
 	}
 
-	if configInvalid {
-		return errors.New("config invalid")
+	if controlPlanes == 0 {
+		return errors.New("no control-plane nodes specified")
 	}
 
-	// TODO: Check that backend is not SQLite if HA is enabled.
+	if controlPlanes > 1 {
+		return errors.New("unimplemented: multiple control-plane nodes")
+
+		// TODO: Check that backend is not SQLite if HA is enabled.
+	}
 
 	return nil
 }
 
-// VerifyServerCount verifies that at least one API server is
-// specified.
-func (c *Config) VerifyServerCount() error {
-	var controlPlanes = 0
-
-	if c.Nodes == nil || len(c.Nodes) == 0 {
-		return errors.New("no nodes specified")
-	}
+// NodesByRole returns a list of nodes based on the specified selector.
+// Use RoleAny to match all nodes, RoleAgent to match all worker nodes,
+// and RoleServer to match all control-plane nodes.
+func (c *Config) NodesByRole(selector Role) []*Node {
+	var nodes []*Node
 
 	for _, node := range c.Nodes {
-		if node.Role == RoleServer {
-			controlPlanes += 1
+		if node.Role == selector || selector == RoleAny {
+			nodes = append(nodes, &node)
 		}
 	}
 
-	if controlPlanes == 0 {
-		return errors.New("no control-plane nodes specified")
-	}
-
-	return nil
+	return nodes
 }
 
 // LoadConfig sets up the configuration parser and loads

pkg/engine/node.go

@@ -0,0 +1,41 @@
+package engine
+
+import "github.com/nicklasfrahm/k3se/pkg/sshx"
+
+const (
+	// Program is used to configure the name of the configuration file.
+	Program = "k3se"
+)
+
+// Node describes the configuration of a node.
+type Node struct {
+	Role      Role        `yaml:"role"`
+	SSH       sshx.Config `yaml:"ssh"`
+	NodeLabel []string    `yaml:"node-label"`
+
+	*sshx.Client `yaml:"-"`
+}
+
+// Connect establishes a connection to the node.
+func (node *Node) Connect(options ...Option) error {
+	opts, err := GetDefaultOptions().Apply(options...)
+	if err != nil {
+		return err
+	}
+
+	node.Client, err = sshx.NewClient(&node.SSH,
+		sshx.WithProxy(opts.SSHProxy),
+		sshx.WithLogger(opts.Logger),
+		sshx.WithTimeout(opts.Timeout),
+	)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Disconnect closes the connection to the node.
+func (node *Node) Disconnect() error {
+	return nil
+}

pkg/rexec/options.go → pkg/engine/options.go

@@ -1,17 +1,19 @@
-package rexec
+package engine
 
 import (
 	"os"
 	"time"
 
 	"github.com/rs/zerolog"
 	"github.com/rs/zerolog/log"
+
+	"github.com/nicklasfrahm/k3se/pkg/sshx"
 )
 
 // Options contains the configuration for an operation.
 type Options struct {
 	Logger   *zerolog.Logger
-	SSHProxy *SSHConfig
+	SSHProxy *sshx.Client
 	Timeout  time.Duration
 }
 
@@ -44,10 +46,27 @@ func GetDefaultOptions() *Options {
 	}
 }
 
-// WithSSHProxy configures an SSH bastion host.
-func WithSSHProxy(sshProxy *SSHConfig) Option {
+// WithLogger allows to use a custom logger.
+func WithLogger(logger *zerolog.Logger) Option {
+	return func(options *Options) error {
+		options.Logger = logger
+		return nil
+	}
+}
+
+// WithSSHProxy allows to use an existing SSH
+// connection as an SSH bastion host.
+func WithSSHProxy(proxy *sshx.Client) Option {
+	return func(options *Options) error {
+		options.SSHProxy = proxy
+		return nil
+	}
+}
+
+// WithTimeout allows to set a custom timeout.
+func WithTimeout(timeout time.Duration) Option {
 	return func(options *Options) error {
-		options.SSHProxy = sshProxy
+		options.Timeout = timeout
 		return nil
 	}
 }

pkg/k3se/diff.go → pkg/ops/diff.go

@@ -1,4 +1,4 @@
-package k3se
+package ops
 
 import (
 	"errors"

pkg/k3se/options.go → pkg/ops/options.go

@@ -1,4 +1,9 @@
-package k3se
+package ops
+
+const (
+	// Program is used to configure the name of the configuration file.
+	Program = "k3se"
+)
 
 // Options contains the configuration for an operation.
 type Options struct {