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/pia/parse_test.go

@@ -0,0 +1,99 @@
+package pia
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net"
+	"strings"
+	"testing"
+
+	loggingMocks "github.com/qdm12/golibs/logging/mocks"
+	"github.com/qdm12/golibs/verification"
+	"github.com/qdm12/private-internet-access-docker/internal/constants"
+	"github.com/qdm12/private-internet-access-docker/internal/models"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func Test_ParseConfig(t *testing.T) {
+	t.Parallel()
+	original, err := ioutil.ReadFile("testdata/ovpn.golden")
+	require.NoError(t, err)
+	exampleLines := strings.Split(string(original), "\n")
+	tests := map[string]struct {
+		lines       []string
+		lookupIPs   []net.IP
+		lookupIPErr error
+		IPs         []net.IP
+		port        uint16
+		device      models.VPNDevice
+		err         error
+	}{
+		"no data": {
+			err: fmt.Errorf("remote line not found in Openvpn configuration"),
+		},
+		"bad remote line": {
+			lines: []string{"remote field2"},
+			err:   fmt.Errorf("line \"remote field2\" misses information"),
+		},
+		"bad remote port": {
+			lines: []string{"remote field2 port"},
+			err:   fmt.Errorf("line \"remote field2 port\" has an invalid port: port \"port\" is not a valid integer"),
+		},
+		"lookupIP error": {
+			lines:       []string{"remote host 1000"},
+			lookupIPErr: fmt.Errorf("lookup error"),
+			err:         fmt.Errorf("lookup error"),
+		},
+		"missing dev line": {
+			lines: []string{"remote host 1994"},
+			err:   fmt.Errorf("device line not found in Openvpn configuration"),
+		},
+		"bad dev line": {
+			lines: []string{"dev   field2 field3"},
+			err:   fmt.Errorf("line \"dev   field2 field3\" misses information"),
+		},
+		"bad device": {
+			lines: []string{"dev xx"},
+			err:   fmt.Errorf("device \"xx0\" is not valid"),
+		},
+		"valid lines": {
+			lines:  []string{"remote host 1194", "dev tap", "blabla"},
+			port:   1194,
+			device: constants.TAP,
+		},
+		"real data": {
+			lines:     exampleLines,
+			lookupIPs: []net.IP{{100, 100, 100, 100}, {100, 100, 200, 200}},
+			IPs:       []net.IP{{100, 100, 100, 100}, {100, 100, 200, 200}},
+			port:      1198,
+			device:    constants.TUN,
+		},
+	}
+	for name, tc := range tests {
+		tc := tc
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+			logger := &loggingMocks.Logger{}
+			logger.On("Info", "%s: parsing openvpn configuration", logPrefix).Once()
+			if tc.err == nil {
+				logger.On("Info", "%s: Found %d PIA server IP addresses, port %d and device %s", logPrefix, len(tc.IPs), tc.port, tc.device).Once()
+			}
+			lookupIP := func(host string) ([]net.IP, error) {
+				return tc.lookupIPs, tc.lookupIPErr
+			}
+			c := &configurator{logger: logger, verifyPort: verification.NewVerifier().VerifyPort, lookupIP: lookupIP}
+			IPs, port, device, err := c.ParseConfig(tc.lines)
+			if tc.err != nil {
+				require.Error(t, err)
+				assert.Equal(t, tc.err.Error(), err.Error())
+			} else {
+				assert.NoError(t, err)
+			}
+			assert.Equal(t, tc.IPs, IPs)
+			assert.Equal(t, tc.port, port)
+			assert.Equal(t, tc.device, device)
+			logger.AssertExpectations(t)
+		})
+	}
+}