cobra/commands: cancel command context on signal

See docker/cli#4599 and
docker/cli#4769.

Since we switched to using the cobra command context instead of
`appcontext`, we need to set up the signal handling that was being
provided by `appcontext`, as well as configuring the context with
the OTEL tracing utilities also used by `appcontext`.

This commit introduces `cobrautil.ConfigureContext` which implements
the pre-existing signal handling logic from `appcontext` and cancels
the command's context when a signal is received, as well as doing
the relevant OTEL config.

Signed-off-by: Laura Brehm <[email protected]>

commands/bake.go

@@ -15,6 +15,7 @@ import (
 	"github.com/docker/buildx/builder"
 	"github.com/docker/buildx/localstate"
 	"github.com/docker/buildx/util/buildflags"
+	"github.com/docker/buildx/util/cobrautil"
 	"github.com/docker/buildx/util/cobrautil/completion"
 	"github.com/docker/buildx/util/confutil"
 	"github.com/docker/buildx/util/desktop"
@@ -261,7 +262,7 @@ func bakeCmd(dockerCli command.Cli, rootOpts *rootOptions) *cobra.Command {
 		Use:     "bake [OPTIONS] [TARGET...]",
 		Aliases: []string{"f"},
 		Short:   "Build from a file",
-		RunE: func(cmd *cobra.Command, args []string) error {
+		RunE: cobrautil.ConfigureContext(func(cmd *cobra.Command, args []string) error {
 			// reset to nil to avoid override is unset
 			if !cmd.Flags().Lookup("no-cache").Changed {
 				cFlags.noCache = nil
@@ -273,7 +274,7 @@ func bakeCmd(dockerCli command.Cli, rootOpts *rootOptions) *cobra.Command {
 			options.metadataFile = cFlags.metadataFile
 			// Other common flags (noCache, pull and progress) are processed in runBake function.
 			return runBake(cmd.Context(), dockerCli, args, options, cFlags)
-		},
+		}),
 		ValidArgsFunction: completion.BakeTargets(options.files),
 	}
 

commands/build.go

@@ -27,6 +27,7 @@ import (
 	"github.com/docker/buildx/store"
 	"github.com/docker/buildx/store/storeutil"
 	"github.com/docker/buildx/util/buildflags"
+	"github.com/docker/buildx/util/cobrautil"
 	"github.com/docker/buildx/util/desktop"
 	"github.com/docker/buildx/util/ioset"
 	"github.com/docker/buildx/util/metrics"
@@ -460,7 +461,7 @@ func buildCmd(dockerCli command.Cli, rootOpts *rootOptions, debugConfig *debug.D
 		Aliases: []string{"b"},
 		Short:   "Start a build",
 		Args:    cli.ExactArgs(1),
-		RunE: func(cmd *cobra.Command, args []string) error {
+		RunE: cobrautil.ConfigureContext(func(cmd *cobra.Command, args []string) error {
 			options.contextPath = args[0]
 			options.builder = rootOpts.builder
 			options.metadataFile = cFlags.metadataFile
@@ -484,7 +485,7 @@ func buildCmd(dockerCli command.Cli, rootOpts *rootOptions, debugConfig *debug.D
 			}
 
 			return runBuild(cmd.Context(), dockerCli, *options)
-		},
+		}),
 		ValidArgsFunction: func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
 			return nil, cobra.ShellCompDirectiveFilterDirs
 		},

commands/create.go

@@ -95,9 +95,9 @@ func createCmd(dockerCli command.Cli) *cobra.Command {
 		Use:   "create [OPTIONS] [CONTEXT|ENDPOINT]",
 		Short: "Create a new builder instance",
 		Args:  cli.RequiresMaxArgs(1),
-		RunE: func(cmd *cobra.Command, args []string) error {
+		RunE: cobrautil.ConfigureContext(func(cmd *cobra.Command, args []string) error {
 			return runCreate(cmd.Context(), dockerCli, options, args)
-		},
+		}),
 		ValidArgsFunction: completion.Disable,
 	}
 

commands/diskusage.go

@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/docker/buildx/builder"
+	"github.com/docker/buildx/util/cobrautil"
 	"github.com/docker/buildx/util/cobrautil/completion"
 	"github.com/docker/cli/cli"
 	"github.com/docker/cli/cli/command"
@@ -110,10 +111,10 @@ func duCmd(dockerCli command.Cli, rootOpts *rootOptions) *cobra.Command {
 		Use:   "du",
 		Short: "Disk usage",
 		Args:  cli.NoArgs,
-		RunE: func(cmd *cobra.Command, args []string) error {
+		RunE: cobrautil.ConfigureContext(func(cmd *cobra.Command, args []string) error {
 			options.builder = rootOpts.builder
 			return runDiskUsage(cmd.Context(), dockerCli, options)
-		},
+		}),
 		ValidArgsFunction: completion.Disable,
 	}
 

commands/imagetools/create.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/distribution/reference"
 	"github.com/docker/buildx/builder"
+	"github.com/docker/buildx/util/cobrautil"
 	"github.com/docker/buildx/util/cobrautil/completion"
 	"github.com/docker/buildx/util/imagetools"
 	"github.com/docker/buildx/util/progress"
@@ -269,10 +270,10 @@ func createCmd(dockerCli command.Cli, opts RootOptions) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "create [OPTIONS] [SOURCE] [SOURCE...]",
 		Short: "Create a new image based on source images",
-		RunE: func(cmd *cobra.Command, args []string) error {
+		RunE: cobrautil.ConfigureContext(func(cmd *cobra.Command, args []string) error {
 			options.builder = *opts.Builder
 			return runCreate(cmd.Context(), dockerCli, options, args)
-		},
+		}),
 		ValidArgsFunction: completion.Disable,
 	}
 

commands/imagetools/inspect.go

@@ -4,6 +4,7 @@ import (
 	"context"
 
 	"github.com/docker/buildx/builder"
+	"github.com/docker/buildx/util/cobrautil"
 	"github.com/docker/buildx/util/cobrautil/completion"
 	"github.com/docker/buildx/util/imagetools"
 	"github.com/docker/cli-docs-tool/annotation"
@@ -48,10 +49,10 @@ func inspectCmd(dockerCli command.Cli, rootOpts RootOptions) *cobra.Command {
 		Use:   "inspect [OPTIONS] NAME",
 		Short: "Show details of an image in the registry",
 		Args:  cli.ExactArgs(1),
-		RunE: func(cmd *cobra.Command, args []string) error {
+		RunE: cobrautil.ConfigureContext(func(cmd *cobra.Command, args []string) error {
 			options.builder = *rootOpts.Builder
 			return runInspect(cmd.Context(), dockerCli, options, args[0])
-		},
+		}),
 		ValidArgsFunction: completion.Disable,
 	}
 

commands/inspect.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/docker/buildx/builder"
 	"github.com/docker/buildx/driver"
+	"github.com/docker/buildx/util/cobrautil"
 	"github.com/docker/buildx/util/cobrautil/completion"
 	"github.com/docker/buildx/util/platformutil"
 	"github.com/docker/cli/cli"
@@ -142,13 +143,13 @@ func inspectCmd(dockerCli command.Cli, rootOpts *rootOptions) *cobra.Command {
 		Use:   "inspect [NAME]",
 		Short: "Inspect current builder instance",
 		Args:  cli.RequiresMaxArgs(1),
-		RunE: func(cmd *cobra.Command, args []string) error {
+		RunE: cobrautil.ConfigureContext(func(cmd *cobra.Command, args []string) error {
 			options.builder = rootOpts.builder
 			if len(args) > 0 {
 				options.builder = args[0]
 			}
 			return runInspect(cmd.Context(), dockerCli, options)
-		},
+		}),
 		ValidArgsFunction: completion.BuilderNames(dockerCli),
 	}
 

commands/ls.go

@@ -99,9 +99,9 @@ func lsCmd(dockerCli command.Cli) *cobra.Command {
 		Use:   "ls",
 		Short: "List builder instances",
 		Args:  cli.ExactArgs(0),
-		RunE: func(cmd *cobra.Command, args []string) error {
+		RunE: cobrautil.ConfigureContext(func(cmd *cobra.Command, args []string) error {
 			return runLs(cmd.Context(), dockerCli, options)
-		},
+		}),
 		ValidArgsFunction: completion.Disable,
 	}
 

commands/prune.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/docker/buildx/builder"
+	"github.com/docker/buildx/util/cobrautil"
 	"github.com/docker/buildx/util/cobrautil/completion"
 	"github.com/docker/cli/cli"
 	"github.com/docker/cli/cli/command"
@@ -134,10 +135,10 @@ func pruneCmd(dockerCli command.Cli, rootOpts *rootOptions) *cobra.Command {
 		Use:   "prune",
 		Short: "Remove build cache",
 		Args:  cli.NoArgs,
-		RunE: func(cmd *cobra.Command, args []string) error {
+		RunE: cobrautil.ConfigureContext(func(cmd *cobra.Command, args []string) error {
 			options.builder = rootOpts.builder
 			return runPrune(cmd.Context(), dockerCli, options)
-		},
+		}),
 		ValidArgsFunction: completion.Disable,
 	}
 

commands/rm.go

@@ -8,6 +8,7 @@ import (
 	"github.com/docker/buildx/builder"
 	"github.com/docker/buildx/store"
 	"github.com/docker/buildx/store/storeutil"
+	"github.com/docker/buildx/util/cobrautil"
 	"github.com/docker/buildx/util/cobrautil/completion"
 	"github.com/docker/cli/cli/command"
 	"github.com/pkg/errors"
@@ -97,7 +98,7 @@ func rmCmd(dockerCli command.Cli, rootOpts *rootOptions) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "rm [OPTIONS] [NAME] [NAME...]",
 		Short: "Remove one or more builder instances",
-		RunE: func(cmd *cobra.Command, args []string) error {
+		RunE: cobrautil.ConfigureContext(func(cmd *cobra.Command, args []string) error {
 			options.builders = []string{rootOpts.builder}
 			if len(args) > 0 {
 				if options.allInactive {
@@ -106,7 +107,7 @@ func rmCmd(dockerCli command.Cli, rootOpts *rootOptions) *cobra.Command {
 				options.builders = args
 			}
 			return runRm(cmd.Context(), dockerCli, options)
-		},
+		}),
 		ValidArgsFunction: completion.BuilderNames(dockerCli),
 	}
 

commands/stop.go

@@ -4,6 +4,7 @@ import (
 	"context"
 
 	"github.com/docker/buildx/builder"
+	"github.com/docker/buildx/util/cobrautil"
 	"github.com/docker/buildx/util/cobrautil/completion"
 	"github.com/docker/cli/cli"
 	"github.com/docker/cli/cli/command"
@@ -37,13 +38,13 @@ func stopCmd(dockerCli command.Cli, rootOpts *rootOptions) *cobra.Command {
 		Use:   "stop [NAME]",
 		Short: "Stop builder instance",
 		Args:  cli.RequiresMaxArgs(1),
-		RunE: func(cmd *cobra.Command, args []string) error {
+		RunE: cobrautil.ConfigureContext(func(cmd *cobra.Command, args []string) error {
 			options.builder = rootOpts.builder
 			if len(args) > 0 {
 				options.builder = args[0]
 			}
 			return runStop(cmd.Context(), dockerCli, options)
-		},
+		}),
 		ValidArgsFunction: completion.BuilderNames(dockerCli),
 	}
 

util/cobrautil/cobrautil.go

@@ -1,6 +1,15 @@
 package cobrautil
 
-import "github.com/spf13/cobra"
+import (
+	"context"
+	"os"
+	"os/signal"
+
+	"github.com/moby/buildkit/util/bklog"
+	detect "github.com/moby/buildkit/util/tracing/env"
+	"github.com/pkg/errors"
+	"github.com/spf13/cobra"
+)
 
 // HideInheritedFlags hides inherited flags
 func HideInheritedFlags(cmd *cobra.Command, hidden ...string) {
@@ -12,3 +21,35 @@ func HideInheritedFlags(cmd *cobra.Command, hidden ...string) {
 		_ = cmd.Flags().MarkHidden(h)
 	}
 }
+
+// ConfigureContext sets up signal handling and hooks into the command's
+// context so that it will be cancelled when signalled, as well as implementing
+// the "hard exit after 3 signals" logic. It also configures OTEL tracing
+// for the relevant context.
+func ConfigureContext(fn func(*cobra.Command, []string) error) func(cmd *cobra.Command, args []string) error {
+	return func(cmd *cobra.Command, args []string) error {
+		ctx := detect.InitContext(cmd.Context())
+		cancellableCtx, cancel := context.WithCancelCause(ctx)
+		ctx = cancellableCtx
+
+		signalLimit := 3
+		s := make(chan os.Signal, signalLimit)
+		signal.Notify(s, interruptSignals...)
+		go func() {
+			retries := 0
+			for {
+				<-s
+				retries++
+				err := errors.Errorf("got %d SIGTERM/SIGINTs, forcing shutdown", retries)
+				cancel(err)
+				if retries >= signalLimit {
+					bklog.G(ctx).Errorf(err.Error())
+					os.Exit(1)
+				}
+			}
+		}()
+
+		cmd.SetContext(ctx)
+		return fn(cmd, args)
+	}
+}

util/cobrautil/signals_unix.go

@@ -0,0 +1,10 @@
+//go:build !windows
+
+package cobrautil
+
+import (
+	"golang.org/x/sys/unix"
+	"os"
+)
+
+var interruptSignals = []os.Signal{unix.SIGTERM, unix.SIGINT}

util/cobrautil/signals_windows.go

@@ -0,0 +1,9 @@
+//go:build windows
+
+package cobrautil
+
+import (
+	"os"
+)
+
+var interruptSignals = []os.Signal{os.Interrupt}