Rewrite of the entrypoint in Golang (#71)

- General improvements
    - Parallel download of only needed files at start
    - Prettier console output with all streams merged (openvpn, unbound, shadowsocks etc.)
    - Simplified Docker final image
    - Faster bootup
- DNS over TLS
    - Finer grain blocking at DNS level: malicious, ads and surveillance
    - Choose your DNS over TLS providers
    - Ability to use multiple DNS over TLS providers for DNS split horizon
    - Environment variables for DNS logging
    - DNS block lists needed are downloaded and built automatically at start, in parallel
- PIA
    - A random region is selected if the REGION parameter is left empty (thanks @rorph for your PR)
    - Routing and iptables adjusted so it can work as a Kubernetes pod sidecar (thanks @rorph for your PR)

internal/shadowsocks/conf_test.go

@@ -0,0 +1,79 @@
+package shadowsocks
+
+import (
+	"fmt"
+	"testing"
+
+	filesMocks "github.com/qdm12/golibs/files/mocks"
+	loggingMocks "github.com/qdm12/golibs/logging/mocks"
+	"github.com/qdm12/private-internet-access-docker/internal/constants"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/mock"
+	"github.com/stretchr/testify/require"
+)
+
+func Test_generateConf(t *testing.T) {
+	t.Parallel()
+	tests := map[string]struct {
+		port     uint16
+		password string
+		data     []byte
+	}{
+		"no data": {
+			data: []byte(`{"server":"0.0.0.0","user":"nonrootuser","method":"chacha20-ietf-poly1305","timeout":30,"fast_open":false,"mode":"tcp_and_udp","port_password":{"0":""},"workers":2,"interface":"tun","nameserver":"127.0.0.1"}`),
+		},
+		"data": {
+			port:     2000,
+			password: "abcde",
+			data:     []byte(`{"server":"0.0.0.0","user":"nonrootuser","method":"chacha20-ietf-poly1305","timeout":30,"fast_open":false,"mode":"tcp_and_udp","port_password":{"2000":"abcde"},"workers":2,"interface":"tun","nameserver":"127.0.0.1"}`),
+		},
+	}
+	for name, tc := range tests {
+		tc := tc
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+			data := generateConf(tc.port, tc.password)
+			assert.Equal(t, tc.data, data)
+		})
+	}
+}
+
+func Test_MakeConf(t *testing.T) {
+	t.Parallel()
+	tests := map[string]struct {
+		writeErr error
+		err      error
+	}{
+		"no write error": {},
+		"write error": {
+			writeErr: fmt.Errorf("error"),
+			err:      fmt.Errorf("error"),
+		},
+	}
+	for name, tc := range tests {
+		tc := tc
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+			logger := &loggingMocks.Logger{}
+			logger.On("Info", "%s: generating configuration file", logPrefix).Once()
+			fileManager := &filesMocks.FileManager{}
+			fileManager.On("WriteToFile",
+				string(constants.ShadowsocksConf),
+				[]byte(`{"server":"0.0.0.0","user":"nonrootuser","method":"chacha20-ietf-poly1305","timeout":30,"fast_open":false,"mode":"tcp_and_udp","port_password":{"2000":"abcde"},"workers":2,"interface":"tun","nameserver":"127.0.0.1"}`),
+				mock.AnythingOfType("files.WriteOptionSetter"),
+				mock.AnythingOfType("files.WriteOptionSetter"),
+			).
+				Return(tc.writeErr).Once()
+			c := &configurator{logger: logger, fileManager: fileManager}
+			err := c.MakeConf(2000, "abcde", 1000, 1001)
+			if tc.err != nil {
+				require.Error(t, err)
+				assert.Equal(t, tc.err.Error(), err.Error())
+			} else {
+				assert.NoError(t, err)
+			}
+			logger.AssertExpectations(t)
+			fileManager.AssertExpectations(t)
+		})
+	}
+}