Split off cli into separate binaries (#37)

* 🎨 Split off cli into separate binaries

This commit splits off the cli into 3 binaries:
- agent
- cli
- provider

The provider now is a separate component that can be tested by itself
and have its own lifecycle. This paves the way to a ligher c3os variant,
HA support and other features that can be provided on runtime.

This is working, but still there are low hanging fruit to care about.

Fixes #14

* 🤖 Add provider bin to releases

* ⚙️ Handle signals

* ⚙️ Reduce buildsize footprint

* 🎨 Scan for providers also in /system/providers

* 🤖 Run goreleaser

* 🎨 Refactoring

internal/machine/openrc/unit.go

@@ -0,0 +1,86 @@
+package openrc
+
+import (
+	"fmt"
+	"io/ioutil"
+	"path/filepath"
+	"strings"
+
+	"github.com/c3os-io/c3os/internal/utils"
+)
+
+type ServiceUnit struct {
+	content string
+	name    string
+	rootdir string
+}
+
+type ServiceOpts func(*ServiceUnit) error
+
+func WithRoot(n string) ServiceOpts {
+	return func(su *ServiceUnit) error {
+		su.rootdir = n
+		return nil
+	}
+}
+
+func WithName(n string) ServiceOpts {
+	return func(su *ServiceUnit) error {
+		su.name = n
+		return nil
+	}
+}
+
+func WithUnitContent(n string) ServiceOpts {
+	return func(su *ServiceUnit) error {
+		su.content = n
+		return nil
+	}
+}
+
+func NewService(opts ...ServiceOpts) (ServiceUnit, error) {
+	s := &ServiceUnit{}
+	for _, o := range opts {
+		if err := o(s); err != nil {
+			return *s, err
+		}
+	}
+	return *s, nil
+}
+
+func (s ServiceUnit) WriteUnit() error {
+	uname := s.name
+
+	if err := ioutil.WriteFile(filepath.Join(s.rootdir, fmt.Sprintf("/etc/init.d/%s", uname)), []byte(s.content), 0755); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// TODO: This is too much k3s specific
+func (s ServiceUnit) OverrideCmd(cmd string) error {
+	cmd = strings.ReplaceAll(cmd, "/usr/bin/k3s ", "")
+	svcDir := filepath.Join(s.rootdir, fmt.Sprintf("/etc/rancher/k3s/%s.env", s.name))
+
+	return ioutil.WriteFile(svcDir, []byte(fmt.Sprintf(`command_args="%s >>/var/log/%s.log 2>&1"`, cmd, s.name)), 0600)
+}
+
+func (s ServiceUnit) Start() error {
+	_, err := utils.SH(fmt.Sprintf("/etc/init.d/%s start", s.name))
+	return err
+}
+
+func (s ServiceUnit) Restart() error {
+	_, err := utils.SH(fmt.Sprintf("/etc/init.d/%s restart", s.name))
+	return err
+}
+
+func (s ServiceUnit) Enable() error {
+	_, err := utils.SH(fmt.Sprintf("ln -sf /etc/init.d/%s /etc/runlevels/default/%s", s.name, s.name))
+	return err
+}
+
+func (s ServiceUnit) StartBlocking() error {
+	return s.Start()
+}