docker: use env variables to configure docker client

Previously when an user use a different DOCKER_HOST we was not able to
connect because we was not reading the environment variables.

This commit change the docker client initialization to read
configuration from environment variables if they exists.

Fixes #525

Signed-off-by: Matheus Alcantara <matheus.alcantara@zup.com.br>

internal/services/docker/client/docker_config.go

@@ -22,7 +22,7 @@ import (
 )
 
 func NewDockerClient() *docker.Client {
-	dockerClient, err := docker.NewClientWithOpts(docker.WithAPIVersionNegotiation())
+	dockerClient, err := docker.NewClientWithOpts(docker.FromEnv, docker.WithAPIVersionNegotiation())
 	if err != nil {
 		logger.LogPanicWithLevel(messages.MsgPanicNotConnectDocker, err)
 	}

internal/services/docker/client/docker_config_test.go

@@ -16,6 +16,7 @@ package client
 
 import (
 	"io"
+	"os"
 	"strings"
 	"testing"
 
@@ -30,6 +31,15 @@ func TestNewDockerAPI(t *testing.T) {
 			NewDockerClient()
 		})
 	})
+
+	t.Run("Should use docker host from environment variable", func(t *testing.T) {
+		dockerHost := "unix:///path/docker/socket"
+		os.Setenv("DOCKER_HOST", dockerHost)
+
+		c := NewDockerClient()
+
+		assert.Equal(t, dockerHost, c.DaemonHost())
+	})
 }
 
 func TestMock(t *testing.T) {