feat(cdk): component dev mode (#911)

This feature is adding the ability to enter development mode of one CDK
component at a time. To do so, developers need to export the environment
variable `LW_CDK_DEV_COMPONENT`

Example:
```
$ export LW_CDK_DEV_COMPONENT=new-component
$ lacework component list
```

That should show you the following output:
```
     STATUS           NAME        VERSION                                       DESCRIPTION
----------------+---------------+---------+---------------------------------------------------------------------------------------
  Not Installed   new-component   0.0.0     create dev specs file '/Users/afiune/.config/lacework/components/new-component/.dev'

Components version: 0.2.0
```

Then you just need to create the dev specs file that contains all the
specifications of your dev component.

Example:
```
cat ~/.config/lacework/components/new-component/.dev
{
  "version": "0.0.1",
  "name": "new-component",
  "description": "A component being developed. Have fun!",
  "type": "CLI_COMMAND",
  "artifacts": []
}
```

Finally, if you try to install the component, you will get an error
message like this one:
```
$ lacework component install my-component

ERROR unable to install component: components under development can't be installed.

Deploy the component manually at '/Users/afiune/.config/lacework/components/my-component/my-component'
```

As the message suggests, deploy the component manually and you should be
good to go.

Signed-off-by: Salim Afiune Maya <[email protected]>

Signed-off-by: Salim Afiune Maya <[email protected]>

lwcomponent/component.go

@@ -64,11 +64,36 @@ func LoadState(client *api.Client) (*State, error) {
 			return s, err
 		}
 
+		s.loadDevComponent()
+
 		return s, s.WriteState()
 	}
 	return nil, errors.New("invalid api client")
 }
 
+// loadDevComponent will load a component that is under development,
+// developers need to export the environment variable 'LW_CDK_DEV_COMPONENT'
+func (s *State) loadDevComponent() {
+	if devComponent := os.Getenv("LW_CDK_DEV_COMPONENT"); devComponent != "" {
+		for i := range s.Components {
+			if s.Components[i].Name == devComponent {
+				// existing component being developed
+				if err := s.Components[i].loadDevSpecs(); err != nil {
+					s.Components[i].Description = err.Error()
+				}
+				return
+			}
+		}
+
+		// component is not yet defined, add it to the state
+		dev := Component{Name: devComponent}
+		if err := dev.loadDevSpecs(); err != nil {
+			dev.Description = err.Error()
+		}
+		s.Components = append(s.Components, dev)
+	}
+}
+
 // LocalState loads the state from the local storage ("Dir()/state")
 func LocalState() (*State, error) {
 	state := new(State)
@@ -150,6 +175,14 @@ func (s State) Install(name string) error {
 		return err
 	}
 
+	// verify development mode
+	if component.underDevelopment() {
+		p, _ := component.Path() // @afiune we don't care if the component exists or not
+		msg := "components under development can't be installed.\n\n" +
+			"Deploy the component manually at '" + p + "'"
+		return errors.New(msg)
+	}
+
 	// @afiune verify if component is in latest
 
 	// @afiune install
@@ -262,6 +295,12 @@ func (c Component) Path() (string, error) {
 
 // CurrentVersion returns the current installed version of the component
 func (c Component) CurrentVersion() (*semver.Version, error) {
+	// development mode, avoid loading the current version,
+	// return latest which is what's inside the '.dev' specs
+	if c.underDevelopment() {
+		return &c.LatestVersion, nil
+	}
+
 	dir, err := c.RootPath()
 	if err != nil {
 		return nil, err
@@ -381,7 +420,54 @@ func (c Component) ArtifactForRunningHost() (*Artifact, bool) {
 	return nil, false
 }
 
+// loadDevSpecs will lookup for the '.dev' specs file under the
+// component root path to load it into the component itself
+func (c *Component) loadDevSpecs() error {
+	dir, err := c.RootPath()
+	if err != nil {
+		return errors.New("unable to detect RootPath")
+	}
+
+	devSpecs := filepath.Join(dir, ".dev")
+	if file.FileExists(devSpecs) {
+		devSpecsBytes, err := ioutil.ReadFile(devSpecs)
+		if err != nil {
+			return errors.Errorf("unable to read %s file", devSpecs)
+		}
+		err = json.Unmarshal(devSpecsBytes, c)
+		if err != nil {
+			return errors.Errorf("unable to unmarshal %s file", devSpecs)
+		}
+	} else {
+		return errors.Errorf("create dev specs file '%s'", devSpecs)
+	}
+
+	return nil
+}
+
+// underDevelopment returns true if the component is under development
+// that is, if the component root path has the '.dev' specs file or, if
+// the environment variable 'LW_CDK_DEV_COMPONENT' matches the component name
+func (c Component) underDevelopment() bool {
+	if os.Getenv("LW_CDK_DEV_COMPONENT") == c.Name {
+		return true
+	}
+
+	dir, err := c.RootPath()
+	if err != nil {
+		return false
+	}
+
+	return file.FileExists(filepath.Join(dir, ".dev"))
+}
+
+// isVerified checks if the component has a valid signature
 func (c Component) isVerified() error {
+	// development mode, avoid verifying
+	if c.underDevelopment() {
+		return nil
+	}
+
 	// get component signature
 	sig, err := c.SignatureFromDisk()
 	if err != nil {