feat(nats): WithConfigFile - pass a configuration file to nats server

modules/nats/nats.go

@@ -58,6 +58,19 @@ func Run(ctx context.Context, img string, opts ...testcontainers.ContainerCustom
 		genericContainerReq.Cmd = append(genericContainerReq.Cmd, []string{"--" + k, v}...)
 	}
 
+	// Pass a configuration file if provided
+	if settings.ConfigFile != nil {
+		genericContainerReq.Cmd = append(genericContainerReq.Cmd, "-config", "/etc/nats.conf")
+		genericContainerReq.Files = append(
+			genericContainerReq.Files,
+			testcontainers.ContainerFile{
+				Reader:            settings.ConfigFile,
+				ContainerFilePath: "/etc/nats.conf",
+				FileMode:          0o644,
+			},
+		)
+	}
+
 	container, err := testcontainers.GenericContainer(ctx, genericContainerReq)
 	var c *NATSContainer
 	if container != nil {

modules/nats/nats_test.go

@@ -1,7 +1,9 @@
 package nats_test
 
 import (
+	"bufio"
 	"context"
+	"strings"
 	"testing"
 
 	"github.com/nats-io/nats.go"
@@ -57,3 +59,52 @@ func TestNATS(t *testing.T) {
 
 	require.Equal(t, "hello", string(msg.Data))
 }
+
+func TestNATSWithConfigFile(t *testing.T) {
+	const natsConf = `
+listen: 0.0.0.0:4222
+authorization {
+    token: "s3cr3t"
+}
+`
+	ctx := context.Background()
+
+	//  createNATSContainer {
+	ctr, err := tcnats.Run(ctx, "nats:2.9", tcnats.WithConfigFile(strings.NewReader(natsConf)))
+	//  }
+	testcontainers.CleanupContainer(t, ctr)
+	require.NoError(t, err)
+
+	// connectionString {
+	uri, err := ctr.ConnectionString(ctx)
+	// }
+	require.NoError(t, err)
+
+	// connect without token {
+	mallory, err := nats.Connect(uri, nats.Name("Mallory"), nats.Token("secret"))
+	// }
+	require.Error(t, err)
+	require.ErrorIs(t, err, nats.ErrAuthorization)
+	t.Cleanup(mallory.Close)
+
+	// connect via token {
+	nc, err := nats.Connect(uri, nats.Name("API Token Test"), nats.Token("s3cr3t"))
+	// }
+	require.NoError(t, err)
+	t.Cleanup(nc.Close)
+
+	// validate /etc/nats.conf mentioned in logs {
+	const expected = "Using configuration file: /etc/nats.conf"
+	logs, err := ctr.Logs(ctx)
+	require.NoError(t, err)
+	sc := bufio.NewScanner(logs)
+	found := false
+	for sc.Scan() {
+		if strings.Contains(sc.Text(), expected) {
+			found = true
+			break
+		}
+	}
+	// }
+	require.Truef(t, found, "expected log line not found: %s", expected)
+}

modules/nats/options.go

@@ -1,18 +1,21 @@
 package nats
 
 import (
+	"io"
 	"strings"
 
 	"github.com/testcontainers/testcontainers-go"
 )
 
 type options struct {
-	CmdArgs map[string]string
+	CmdArgs    map[string]string
+	ConfigFile io.Reader
 }
 
 func defaultOptions() options {
 	return options{
-		CmdArgs: make(map[string]string, 0),
+		CmdArgs:    make(map[string]string, 0),
+		ConfigFile: nil,
 	}
 }
 
@@ -49,3 +52,11 @@ func WithArgument(flag string, value string) CmdOption {
 		o.CmdArgs[flag] = value
 	}
 }
+
+// WithConfigFile pass io.Reader to the NATS container as /etc/nats.conf
+// Changes of a connectivity (listen address, or ports) may break a testcontainer
+func WithConfigFile(config io.Reader) CmdOption {
+	return func(o *options) {
+		o.ConfigFile = config
+	}
+}