Changes for new version of esplora image (#62)

* changes for new version of esplora image

* add electrs port and esplora url env vars in compose yaml files

* wrap viper methods into Config type and use constants package

* add controller to interact with nigiri resources:
 * .env for docker-compose
 * docker daemon
 * json config file

* add use of constants and config packages and change start flag from --port to --env

* add package for global constants and variables

* add use of controller and constants packages instead of local methods and vars

* bump version

* use contants in logs command tests

cli/controller/parser.go

@@ -0,0 +1,58 @@
+package controller
+
+import (
+	"encoding/json"
+	"fmt"
+	"path/filepath"
+
+	"github.com/vulpemventures/nigiri/cli/constants"
+)
+
+// Parser implements functions for parsing flags, JSON files
+// and system directories passed to the CLI commands
+type Parser struct {
+	services map[string]bool
+}
+
+func newParser(services map[string]bool) *Parser {
+	p := &Parser{services}
+	return p
+}
+
+func (p *Parser) parseNetwork(network string) error {
+	for _, n := range constants.AvaliableNetworks {
+		if network == n {
+			return nil
+		}
+	}
+	return constants.ErrInvalidNetwork
+}
+
+func (p *Parser) parseDatadir(path string) error {
+	if !filepath.IsAbs(path) {
+		return constants.ErrInvalidDatadir
+	}
+	return nil
+}
+
+func (p *Parser) parseEnvJSON(strJSON string) (string, error) {
+	// merge default json and incoming json by parsing DefaultEnv to
+	// envJSON type and then parsing the incoming json using the same variable
+	var parsedJSON envJSON
+	defaultJSON, _ := json.Marshal(constants.DefaultEnv)
+	json.Unmarshal(defaultJSON, &parsedJSON)
+	err := json.Unmarshal([]byte(strJSON), &parsedJSON)
+	if err != nil {
+		fmt.Println(err)
+		return "", constants.ErrMalformedJSON
+	}
+	merged, _ := json.Marshal(parsedJSON)
+	return string(merged), nil
+}
+
+func (p *Parser) parseServiceName(name string) error {
+	if !p.services[name] {
+		return constants.ErrInvalidServiceName
+	}
+	return nil
+}