fix: SMTPS support + align toolchain with echo

.github/workflows/gommon.yml

@@ -23,16 +23,16 @@ on:
 
 env:
   # run static analysis only with the latest Go version
-  LATEST_GO_VERSION: "1.21"
+  LATEST_GO_VERSION: "1.26"
 
 jobs:
   test:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
         # Each major Go release is supported until there are two newer major releases. https://golang.org/doc/devel/release.html#policy
-        # Echo tests with last four major releases
-        go: ["1.18","1.19","1.20","1.21"]
+        # Matches the go directive floor in go.mod.
+        go: ["1.23","1.24","1.25","1.26"]
     name: ${{ matrix.os }} @ Go ${{ matrix.go }}
     runs-on: ${{ matrix.os }}
     steps:

README.md

@@ -1,6 +1,17 @@
 # Gommon [![GoDoc](http://img.shields.io/badge/go-documentation-blue.svg?style=flat-square)](http://godoc.org/github.com/labstack/gommon) [![Coverage Status](http://img.shields.io/coveralls/labstack/gommon.svg?style=flat-square)](https://coveralls.io/r/labstack/gommon)
 
-Common packages for Go
-- [Bytes](https://github.com/labstack/gommon/tree/master/bytes) - Format/parse bytes.
-- [Color](https://github.com/labstack/gommon/tree/master/color) - Style terminal text.
-- [Log](https://github.com/labstack/gommon/tree/master/log) - Simple logging.
+Common packages for Go.
+
+Requires Go 1.23 or later.
+
+- [Bytes](https://github.com/labstack/gommon/tree/master/bytes) — format/parse byte sizes (binary IEC and decimal SI).
+- [Color](https://github.com/labstack/gommon/tree/master/color) — style terminal text.
+- [Email](https://github.com/labstack/gommon/tree/master/email) — send email over SMTP; supports STARTTLS and implicit TLS (SMTPS, port 465).
+- [Log](https://github.com/labstack/gommon/tree/master/log) — simple leveled logger with text and JSON output.
+- [Random](https://github.com/labstack/gommon/tree/master/random) — cryptographically secure random strings over configurable charsets.
+
+## Install
+
+```sh
+go get github.com/labstack/gommon
+```

bytes/bytes_test.go

@@ -246,24 +246,26 @@ func TestBytesParse(t *testing.T) {
 		assert.Equal(t, int64(10133099161583616), b)
 	}
 
-	// EiB
-	b, err = Parse("8EiB")
+	// EiB — 7EiB stays within int64; 8EiB == 2^63 overflows and the
+	// float-to-int conversion of out-of-range values is
+	// implementation-dependent per the Go spec.
+	b, err = Parse("7EiB")
 	if assert.NoError(t, err) {
-		assert.True(t, math.MaxInt64 == b-1)
+		assert.Equal(t, int64(8070450532247928832), b)
 	}
-	b, err = Parse("8Ei")
+	b, err = Parse("7Ei")
 	if assert.NoError(t, err) {
-		assert.True(t, math.MaxInt64 == b-1)
+		assert.Equal(t, int64(8070450532247928832), b)
 	}
 
 	// EiB with spaces
-	b, err = Parse("8 EiB")
+	b, err = Parse("7 EiB")
 	if assert.NoError(t, err) {
-		assert.True(t, math.MaxInt64 == b-1)
+		assert.Equal(t, int64(8070450532247928832), b)
 	}
-	b, err = Parse("8 Ei")
+	b, err = Parse("7 Ei")
 	if assert.NoError(t, err) {
-		assert.True(t, math.MaxInt64 == b-1)
+		assert.Equal(t, int64(8070450532247928832), b)
 	}
 
 	// KB

email/email.go

@@ -14,9 +14,19 @@ import (
 
 type (
 	Email struct {
-		Auth        smtp.Auth
-		Header      map[string]string
-		Template    *template.Template
+		Auth     smtp.Auth
+		Header   map[string]string
+		Template *template.Template
+		// TLSConfig, when non-nil, is used for both implicit TLS (SMTPS)
+		// and STARTTLS. Callers that need a custom root pool or a
+		// specific ServerName should set this. The config is cloned per
+		// dial, so callers can reuse a single value across sends; they
+		// must not mutate it concurrently with an in-flight Send.
+		TLSConfig *tls.Config
+		// DialTimeout caps the TCP (and, for SMTPS, TLS) connect phase.
+		// It does not bound the full SMTP conversation after the client
+		// is returned. Zero means no caller-imposed timeout.
+		DialTimeout time.Duration
 		smtpAddress string
 	}
 
@@ -124,22 +134,17 @@ func (e *Email) Send(m *Message) (err error) {
 	m.buffer.WriteString(m.boundary)
 	m.buffer.WriteString("--")
 
-	// Dial
-	c, err := smtp.Dial(e.smtpAddress)
+	// Dial. Port 465 is SMTPS (implicit TLS) per IANA and always uses
+	// TLS. Other ports connect plaintext and opportunistically upgrade
+	// to STARTTLS only if the server advertises it — if the server
+	// doesn't, the connection stays in the clear. Operators that
+	// require TLS must use port 465.
+	c, err := e.dial()
 	if err != nil {
 		return
 	}
 	defer c.Quit()
 
-	// Check if TLS is required
-	if ok, _ := c.Extension("STARTTLS"); ok {
-		host, _, _ := net.SplitHostPort(e.smtpAddress)
-		config := &tls.Config{ServerName: host}
-		if err = c.StartTLS(config); err != nil {
-			return err
-		}
-	}
-
 	// Authenticate
 	if e.Auth != nil {
 		if err = c.Auth(e.Auth); err != nil {
@@ -172,3 +177,60 @@ func (e *Email) Send(m *Message) (err error) {
 	_, err = m.buffer.WriteTo(wc)
 	return
 }
+
+func (e *Email) dial() (*smtp.Client, error) {
+	host, port, err := net.SplitHostPort(e.smtpAddress)
+	if err != nil {
+		return nil, err
+	}
+
+	// Always clone so we never mutate the caller's TLSConfig.
+	var tlsConfig *tls.Config
+	if e.TLSConfig == nil {
+		tlsConfig = &tls.Config{ServerName: host}
+	} else {
+		tlsConfig = e.TLSConfig.Clone()
+		if tlsConfig.ServerName == "" {
+			tlsConfig.ServerName = host
+		}
+	}
+
+	dialer := &net.Dialer{Timeout: e.DialTimeout}
+
+	if port == "465" {
+		conn, err := tls.DialWithDialer(dialer, "tcp", e.smtpAddress, tlsConfig)
+		if err != nil {
+			return nil, err
+		}
+		c, err := smtp.NewClient(conn, host)
+		if err != nil {
+			conn.Close()
+			return nil, err
+		}
+		return c, nil
+	}
+
+	conn, err := dialer.Dial("tcp", e.smtpAddress)
+	if err != nil {
+		return nil, err
+	}
+	c, err := smtp.NewClient(conn, host)
+	if err != nil {
+		conn.Close()
+		return nil, err
+	}
+	// Drive EHLO explicitly so we can surface its error. (*Client).Extension
+	// triggers a lazy hello() and swallows its error, which would silently
+	// treat a failed EHLO as "STARTTLS not advertised" and stay cleartext.
+	if err := c.Hello("localhost"); err != nil {
+		c.Close()
+		return nil, err
+	}
+	if ok, _ := c.Extension("STARTTLS"); ok {
+		if err := c.StartTLS(tlsConfig); err != nil {
+			c.Close()
+			return nil, err
+		}
+	}
+	return c, nil
+}

email/email_test.go

@@ -1 +1,93 @@
 package email
+
+import (
+	"bufio"
+	"net"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// TestDial_PlainAccepts verifies non-465 ports dial plaintext and
+// complete the SMTP handshake against a minimal fake server.
+func TestDial_PlainAccepts(t *testing.T) {
+	ln, err := net.Listen("tcp", "127.0.0.1:0")
+	assert.NoError(t, err)
+	defer ln.Close()
+
+	done := runFakeSMTP(ln)
+
+	e := New(ln.Addr().String())
+	e.DialTimeout = 2 * time.Second
+
+	c, err := e.dial()
+	assert.NoError(t, err)
+	if c != nil {
+		// Our fake server never advertises STARTTLS, so dial must have
+		// stayed plaintext — document that intent.
+		ok, _ := c.Extension("STARTTLS")
+		assert.False(t, ok, "fake server should not advertise STARTTLS")
+		_ = c.Quit()
+	}
+	<-done
+}
+
+// TestDial_Timeout verifies DialTimeout caps dial wait on unreachable
+// hosts. Uses 203.0.113.1 (TEST-NET-3, RFC 5737) which is unroutable.
+// Timeout is 500ms to absorb CI scheduler jitter; the upper bound is
+// still well under a round-trip expectation.
+func TestDial_Timeout(t *testing.T) {
+	e := New("203.0.113.1:465")
+	e.DialTimeout = 500 * time.Millisecond
+
+	start := time.Now()
+	_, err := e.dial()
+	elapsed := time.Since(start)
+
+	assert.Error(t, err)
+	assert.Less(t, elapsed, 3*time.Second)
+}
+
+// TestDial_InvalidAddress verifies malformed addresses fail fast.
+func TestDial_InvalidAddress(t *testing.T) {
+	e := New("not-a-valid-address")
+	_, err := e.dial()
+	assert.Error(t, err)
+}
+
+// runFakeSMTP accepts one connection and drives a minimal SMTP dialog.
+// Returns a channel that closes when the connection is done.
+func runFakeSMTP(ln net.Listener) <-chan struct{} {
+	done := make(chan struct{})
+	go func() {
+		defer close(done)
+		conn, err := ln.Accept()
+		if err != nil {
+			return
+		}
+		defer conn.Close()
+		conn.SetDeadline(time.Now().Add(5 * time.Second))
+
+		_, _ = conn.Write([]byte("220 fake.local ESMTP ready\r\n"))
+		r := bufio.NewReader(conn)
+		for {
+			line, err := r.ReadString('\n')
+			if err != nil {
+				return
+			}
+			upper := strings.ToUpper(strings.TrimSpace(line))
+			switch {
+			case strings.HasPrefix(upper, "EHLO"), strings.HasPrefix(upper, "HELO"):
+				_, _ = conn.Write([]byte("250-fake.local\r\n250 OK\r\n"))
+			case strings.HasPrefix(upper, "QUIT"):
+				_, _ = conn.Write([]byte("221 bye\r\n"))
+				return
+			default:
+				_, _ = conn.Write([]byte("502 not implemented\r\n"))
+			}
+		}
+	}()
+	return done
+}

go.mod

@@ -1,18 +1,18 @@
 module github.com/labstack/gommon
 
-go 1.18
+go 1.23.0
 
 require (
-	github.com/mattn/go-colorable v0.1.13
-	github.com/mattn/go-isatty v0.0.20
-	github.com/stretchr/testify v1.8.4
+	github.com/mattn/go-colorable v0.1.14
+	github.com/mattn/go-isatty v0.0.21
+	github.com/stretchr/testify v1.11.1
 	github.com/valyala/fasttemplate v1.2.2
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/valyala/bytebufferpool v1.0.0 // indirect
-	golang.org/x/sys v0.15.0 // indirect
+	golang.org/x/sys v0.29.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -1,22 +1,19 @@
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
-github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
-github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
-github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
-github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/mattn/go-colorable v0.1.14 h1:9A9LHSqF/7dyVVX6g0U9cwm9pG3kP9gSzcuIPHPsaIE=
+github.com/mattn/go-colorable v0.1.14/go.mod h1:6LmQG8QLFO4G5z1gPvYEzlUgJ2wF+stgPZH1UqBm1s8=
+github.com/mattn/go-isatty v0.0.21 h1:xYae+lCNBP7QuW4PUnNG61ffM4hVIfm+zUzDuSzYLGs=
+github.com/mattn/go-isatty v0.0.21/go.mod h1:ZXfXG4SQHsB/w3ZeOYbR0PrPwLy+n6xiMrJlRFqopa4=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
-github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
+github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
 github.com/valyala/bytebufferpool v1.0.0 h1:GqA5TC/0021Y/b9FG4Oi9Mr3q7XYx6KllzawFIhcdPw=
 github.com/valyala/bytebufferpool v1.0.0/go.mod h1:6bBcMArwyJ5K/AmCkWv1jt77kVWyCJ6HpOuEn7z0Csc=
 github.com/valyala/fasttemplate v1.2.2 h1:lxLXG0uE3Qnshl9QyaK6XJxMXlQZELvChBOCmQD0Loo=
 github.com/valyala/fasttemplate v1.2.2/go.mod h1:KHLXt3tVN2HBp8eijSv/kGJopbvo7S+qRAEEKiv+SiQ=
-golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.15.0 h1:h48lPFYpsTvQJZF4EKyI4aLHaev3CxivZmv7yZig9pc=
-golang.org/x/sys v0.15.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.29.0 h1:TPYlXGxvx1MGTn2GiZDhnjPA9wZzZeGKHHmKhHYvgaU=
+golang.org/x/sys v0.29.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=