Adds context (#18)

internal/provider/default/default.go

@@ -1,6 +1,7 @@
 package local
 
 import (
+	"context"
 	"fmt"
 	"log"
 	"net/mail"
@@ -22,7 +23,15 @@ const (
 )
 
 // Send the email to Mailhog.
-func Send(to []string, msg *mail.Message) error {
+func Send(ctx context.Context, to []string, msg *mail.Message) error {
+	// The GO SMTP package is difficult to cancel using context.
+	// This provider should only ever be used for local development tasks.
+	go func() {
+		<-ctx.Done()
+		fmt.Println("Context cancelled")
+		os.Exit(1)
+	}()
+
 	data, err := mailutils.MessageToBytes(msg)
 	if err != nil {
 		return err
@@ -38,7 +47,7 @@ func Send(to []string, msg *mail.Message) error {
 	}
 
 	from := os.Getenv(EnvFrom)
-	if addr == "" {
+	if from == "" {
 		addr = FallbackFrom
 	}
 

internal/provider/ses/ses.go

@@ -20,8 +20,8 @@ import (
 const AccessKeyPrefix = "AKIA"
 
 // Send email via AWS SES.
-func Send(region, username, password, from string, to []string, msg *mail.Message) error {
-	cfg, err := config.LoadDefaultConfig(context.TODO(),
+func Send(ctx context.Context, region, username, password, from string, to []string, msg *mail.Message) error {
+	cfg, err := config.LoadDefaultConfig(ctx,
 		config.WithRegion(region),
 		config.WithCredentialsProvider(
 			credentials.NewStaticCredentialsProvider(username, password, ""),
@@ -53,7 +53,7 @@ func Send(region, username, password, from string, to []string, msg *mail.Messag
 		Source: aws.String(from),
 	}
 
-	output, err := ses.NewFromConfig(cfg).SendRawEmail(context.TODO(), input)
+	output, err := ses.NewFromConfig(cfg).SendRawEmail(ctx, input)
 	if err != nil {
 		return fmt.Errorf("failed to send message via ses %w", err)
 	}

main.go

@@ -1,15 +1,16 @@
 package main
 
 import (
+	"context"
 	"errors"
 	"log"
 	"net/mail"
 	"os"
 	"strings"
 
 	kingpin "github.com/alecthomas/kingpin/v2"
-
 	skprconfig "github.com/skpr/go-config"
+
 	defaultprovider "github.com/skpr/mail/internal/provider/default"
 	"github.com/skpr/mail/internal/provider/ses"
 )
@@ -38,6 +39,7 @@ var (
 	cliFrom              = kingpin.Flag("from", "The from address (ignored)").Short('f').String()
 	cliRecipientsFromMsg = kingpin.Flag("to-from-message", "Read message for to (ignored)").Short('t').Bool()
 	cliIgnoreDots        = kingpin.Flag("ignore-dots", "Ignore dots alone on lines by themselves in incoming messages (ignored).").Short('i').Bool()
+	cliTimeout           = kingpin.Flag("timeout", "How long to wait before timing out and exiting.").Default("30s").Duration()
 )
 
 func main() {
@@ -73,18 +75,21 @@ func main() {
 		log.Fatalf("failed to read message from stdin: %s", err)
 	}
 
-	err = send(region, username, password, from, *cliTo, msg)
+	ctx, cancel := context.WithTimeout(context.Background(), *cliTimeout)
+	defer cancel()
+
+	err = send(ctx, region, username, password, from, *cliTo, msg)
 	if err != nil {
 		log.Fatalf("failed to send message: %s", err)
 	}
 }
 
 // Send email based on parameters.
-func send(region, username, password, from string, to []string, msg *mail.Message) error {
+func send(ctx context.Context, region, username, password, from string, to []string, msg *mail.Message) error {
 	// Use AWS if the credentials match what we would expect for IAM.
 	if strings.HasPrefix(username, ses.AccessKeyPrefix) {
-		return ses.Send(region, username, password, from, to, msg)
+		return ses.Send(ctx, region, username, password, from, to, msg)
 	}
 
-	return defaultprovider.Send(to, msg)
+	return defaultprovider.Send(ctx, to, msg)
 }