Add GC for docker images

Author: jsoriano

internal/common/bytesize.go

@@ -0,0 +1,168 @@
+// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+// or more contributor license agreements. Licensed under the Elastic License;
+// you may not use this file except in compliance with the Elastic License.
+
+package common
+
+import (
+	"encoding/json"
+	"fmt"
+	"math"
+	"regexp"
+	"strconv"
+
+	"gopkg.in/yaml.v3"
+)
+
+// Common units for sizes in bytes.
+const (
+	Byte     = ByteSize(1)
+	KiloByte = 1024 * Byte
+	MegaByte = 1024 * KiloByte
+	GigaByte = 1024 * MegaByte
+)
+
+const (
+	byteString     = "B"
+	kiloByteString = "KB"
+	megaByteString = "MB"
+	gigaByteString = "GB"
+)
+
+// ByteSize represents the size of a file.
+type ByteSize uint64
+
+// Ensure FileSize implements these interfaces.
+var (
+	_ json.Marshaler   = new(ByteSize)
+	_ json.Unmarshaler = new(ByteSize)
+	_ yaml.Marshaler   = new(ByteSize)
+	_ yaml.Unmarshaler = new(ByteSize)
+)
+
+func parseFileSizeInt(s string) (uint64, error) {
+	// os.FileInfo reports size as int64, don't support bigger numbers.
+	maxBitSize := 63
+	return strconv.ParseUint(s, 10, maxBitSize)
+}
+
+// MarshalJSON implements the json.Marshaler interface for FileSize, it returns
+// the string representation in a format that can be unmarshaled back to an
+// equivalent value.
+func (s ByteSize) MarshalJSON() ([]byte, error) {
+	return []byte(`"` + s.String() + `"`), nil
+}
+
+// MarshalYAML implements the yaml.Marshaler interface for FileSize, it returns
+// the string representation in a format that can be unmarshaled back to an
+// equivalent value.
+func (s ByteSize) MarshalYAML() (interface{}, error) {
+	return s.String(), nil
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface for FileSize.
+func (s *ByteSize) UnmarshalJSON(d []byte) error {
+	// Support unquoted plain numbers.
+	bytes, err := parseFileSizeInt(string(d))
+	if err == nil {
+		*s = ByteSize(bytes)
+		return nil
+	}
+
+	var text string
+	err = json.Unmarshal(d, &text)
+	if err != nil {
+		return err
+	}
+
+	return s.unmarshalString(text)
+}
+
+// UnmarshalYAML implements the yaml.Unmarshaler interface for FileSize.
+func (s *ByteSize) UnmarshalYAML(value *yaml.Node) error {
+	// Support unquoted plain numbers.
+	bytes, err := parseFileSizeInt(value.Value)
+	if err == nil {
+		*s = ByteSize(bytes)
+		return nil
+	}
+
+	return s.unmarshalString(value.Value)
+}
+
+var bytesPattern = regexp.MustCompile(fmt.Sprintf(`^(\d+(\.\d+)?)(%s|%s|%s|%s|)$`, byteString, kiloByteString, megaByteString, gigaByteString))
+
+func (s *ByteSize) unmarshalString(text string) error {
+	match := bytesPattern.FindStringSubmatch(text)
+	if len(match) < 3 {
+		return fmt.Errorf("invalid format for size in bytes (%s)", text)
+	}
+
+	if match[2] == "" {
+		q, err := parseFileSizeInt(match[1])
+		if err != nil {
+			return fmt.Errorf("invalid format for size in bytes (%s): %w", text, err)
+		}
+
+		unit := match[3]
+		switch unit {
+		case gigaByteString:
+			*s = ByteSize(q) * GigaByte
+		case megaByteString:
+			*s = ByteSize(q) * MegaByte
+		case kiloByteString:
+			*s = ByteSize(q) * KiloByte
+		case byteString, "":
+			*s = ByteSize(q) * Byte
+		default:
+			return fmt.Errorf("invalid unit for filesize (%s): %s", text, unit)
+		}
+	} else {
+		q, err := strconv.ParseFloat(match[1], 64)
+		if err != nil {
+			return fmt.Errorf("invalid format for size in bytes (%s): %w", text, err)
+		}
+
+		unit := match[3]
+		switch unit {
+		case gigaByteString:
+			*s = approxFloat(q, GigaByte)
+		case megaByteString:
+			*s = approxFloat(q, MegaByte)
+		case kiloByteString:
+			*s = approxFloat(q, KiloByte)
+		case byteString, "":
+			*s = approxFloat(q, Byte)
+		default:
+			return fmt.Errorf("invalid unit for filesize (%s): %s", text, unit)
+		}
+	}
+
+	return nil
+}
+
+func approxFloat(n float64, unit ByteSize) ByteSize {
+	approx := n * float64(unit)
+	return ByteSize(math.Round(approx))
+}
+
+// String returns the string representation of the FileSize.
+func (s ByteSize) String() string {
+	format := func(q ByteSize, unit string) string {
+		return fmt.Sprintf("%d%s", q, unit)
+	}
+
+	if s >= GigaByte && (s%GigaByte == 0) {
+		return format(s/GigaByte, gigaByteString)
+	}
+
+	if s >= MegaByte && (s%MegaByte == 0) {
+		return format(s/MegaByte, megaByteString)
+	}
+
+	if s >= KiloByte && (s%KiloByte == 0) {
+		return format(s/KiloByte, kiloByteString)
+	}
+
+	return format(s, byteString)
+}

internal/common/bytesize_test.go

@@ -0,0 +1,103 @@
+// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+// or more contributor license agreements. Licensed under the Elastic License;
+// you may not use this file except in compliance with the Elastic License.
+
+package common
+
+import (
+	"encoding/json"
+	"testing"
+
+	"gopkg.in/yaml.v3"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestFileSizeMarshallJSON(t *testing.T) {
+	cases := []struct {
+		fileSize ByteSize
+		expected string
+	}{
+		{ByteSize(0), `"0B"`},
+		{ByteSize(1024), `"1KB"`},
+		{ByteSize(1025), `"1025B"`},
+		{5 * MegaByte, `"5MB"`},
+		{5 * GigaByte, `"5GB"`},
+	}
+
+	for _, c := range cases {
+		t.Run(c.expected, func(t *testing.T) {
+			d, err := json.Marshal(c.fileSize)
+			require.NoError(t, err)
+			assert.Equal(t, c.expected, string(d))
+		})
+	}
+}
+
+func TestFileSizeMarshallYAML(t *testing.T) {
+	cases := []struct {
+		fileSize ByteSize
+		expected string
+	}{
+		{ByteSize(0), "0B\n"},
+		{ByteSize(1024), "1KB\n"},
+		{ByteSize(1025), "1025B\n"},
+		{5 * MegaByte, "5MB\n"},
+		{5 * GigaByte, "5GB\n"},
+	}
+
+	for _, c := range cases {
+		t.Run(c.expected, func(t *testing.T) {
+			d, err := yaml.Marshal(c.fileSize)
+			require.NoError(t, err)
+			assert.Equal(t, c.expected, string(d))
+		})
+	}
+}
+
+func TestFileSizeUnmarshal(t *testing.T) {
+	t.Run("json", func(t *testing.T) {
+		testFileSizeUnmarshalFormat(t, json.Unmarshal)
+	})
+	t.Run("yaml", func(t *testing.T) {
+		testFileSizeUnmarshalFormat(t, yaml.Unmarshal)
+	})
+}
+
+func testFileSizeUnmarshalFormat(t *testing.T, unmarshaler func([]byte, interface{}) error) {
+	cases := []struct {
+		json     string
+		expected ByteSize
+		valid    bool
+	}{
+		{"0", 0, true},
+		{"1024", 1024 * Byte, true},
+		{`"1024"`, 1024 * Byte, true},
+		{`"1024B"`, 1024 * Byte, true},
+		{`"10MB"`, 10 * MegaByte, true},
+		{`"40GB"`, 40 * GigaByte, true},
+		{`"56.21GB"`, approxFloat(56.21, GigaByte), true},
+		{`"2KB"`, 2 * KiloByte, true},
+		{`"KB"`, 0, false},
+		{`"1s"`, 0, false},
+		{`""`, 0, false},
+		{`"B"`, 0, false},
+		{`"-200MB"`, 0, false},
+		{`"-1"`, 0, false},
+		{`"10000000000000000000MB"`, 0, false},
+	}
+
+	for _, c := range cases {
+		t.Run(c.json, func(t *testing.T) {
+			var found ByteSize
+			err := unmarshaler([]byte(c.json), &found)
+			if c.valid {
+				require.NoError(t, err)
+				assert.Equal(t, c.expected, found)
+			} else {
+				require.Error(t, err)
+			}
+		})
+	}
+}

internal/compose/compose.go

@@ -14,6 +14,7 @@ import (
 	"os"
 	"os/exec"
 	"regexp"
+	"slices"
 	"strconv"
 	"strings"
 	"time"
@@ -60,7 +61,23 @@ type Config struct {
 	Services map[string]service
 }
 
+// Images lists the images found in the configuration.
+func (c *Config) Images() []string {
+	var images []string
+	for _, service := range c.Services {
+		if service.Image == "" {
+			continue
+		}
+		if slices.Contains(images, service.Image) {
+			continue
+		}
+		images = append(images, service.Image)
+	}
+	return images
+}
+
 type service struct {
+	Image       string
 	Ports       []portMapping
 	Environment map[string]string
 }