client: refactor ContainerLogs to wrap result

Signed-off-by: Austin Vazquez <austin.vazquez@docker.com>

client/container_logs.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io"
 	"net/url"
+	"sync"
 	"time"
 
 	"github.com/moby/moby/client/internal/timestamp"
@@ -22,6 +23,12 @@ type ContainerLogsOptions struct {
 	Details    bool
 }
 
+// ContainerLogsResult is the result of a container logs operation.
+type ContainerLogsResult struct {
+	rc    io.ReadCloser
+	close func() error
+}
+
 // ContainerLogs returns the logs generated by a container in an [io.ReadCloser].
 // It's up to the caller to close the stream.
 //
@@ -48,10 +55,10 @@ type ContainerLogsOptions struct {
 // [stdcopy.StdType]: https://pkg.go.dev/github.com/moby/moby/api/pkg/stdcopy#StdType
 // [Stdout]: https://pkg.go.dev/github.com/moby/moby/api/pkg/stdcopy#Stdout
 // [Stderr]: https://pkg.go.dev/github.com/moby/moby/api/pkg/stdcopy#Stderr
-func (cli *Client) ContainerLogs(ctx context.Context, containerID string, options ContainerLogsOptions) (io.ReadCloser, error) {
+func (cli *Client) ContainerLogs(ctx context.Context, containerID string, options ContainerLogsOptions) (ContainerLogsResult, error) {
 	containerID, err := trimID("container", containerID)
 	if err != nil {
-		return nil, err
+		return ContainerLogsResult{}, err
 	}
 
 	query := url.Values{}
@@ -66,7 +73,7 @@ func (cli *Client) ContainerLogs(ctx context.Context, containerID string, option
 	if options.Since != "" {
 		ts, err := timestamp.GetTimestamp(options.Since, time.Now())
 		if err != nil {
-			return nil, fmt.Errorf(`invalid value for "since": %w`, err)
+			return ContainerLogsResult{}, fmt.Errorf(`invalid value for "since": %w`, err)
 		}
 		query.Set("since", ts)
 	}
@@ -74,7 +81,7 @@ func (cli *Client) ContainerLogs(ctx context.Context, containerID string, option
 	if options.Until != "" {
 		ts, err := timestamp.GetTimestamp(options.Until, time.Now())
 		if err != nil {
-			return nil, fmt.Errorf(`invalid value for "until": %w`, err)
+			return ContainerLogsResult{}, fmt.Errorf(`invalid value for "until": %w`, err)
 		}
 		query.Set("until", ts)
 	}
@@ -94,7 +101,33 @@ func (cli *Client) ContainerLogs(ctx context.Context, containerID string, option
 
 	resp, err := cli.get(ctx, "/containers/"+containerID+"/logs", query, nil)
 	if err != nil {
-		return nil, err
+		return ContainerLogsResult{}, err
 	}
-	return resp.Body, nil
+	return newContainerLogsResult(resp.Body), nil
+}
+
+func newContainerLogsResult(rc io.ReadCloser) ContainerLogsResult {
+	if rc == nil {
+		panic("rc cannot be nil")
+	}
+	return ContainerLogsResult{
+		rc:    rc,
+		close: sync.OnceValue(rc.Close),
+	}
+}
+
+// Read implements the io.Reader interface.
+func (r ContainerLogsResult) Read(p []byte) (n int, err error) {
+	if r.rc == nil {
+		return 0, io.EOF
+	}
+	return r.rc.Read(p)
+}
+
+// Close closes the underlying reader.
+func (r ContainerLogsResult) Close() error {
+	if r.close == nil {
+		return nil
+	}
+	return r.close()
 }