From 413b3773a0459dbb657fccf05227f43290c94466 Mon Sep 17 00:00:00 2001
From: Spencer Brower <foxtrotalphalima@gmail.com>
Date: Tue, 14 Apr 2020 20:32:21 -0400
Subject: [PATCH] feat: Added ability to use `exec` on filesystems. Currently
 works only for the docker plugin.

---
 plugin/docker/container.go |  2 +-
 plugin/types.go            |  3 ++
 volume/core.go             |  5 +++-
 volume/execable_dir.go     | 59 ++++++++++++++++++++++++++++++++++++++
 volume/fs.go               |  6 ++++
 5 files changed, 73 insertions(+), 2 deletions(-)
 create mode 100644 volume/execable_dir.go

diff --git a/plugin/docker/container.go b/plugin/docker/container.go
index 4992afd1e..351afbe45 100644
--- a/plugin/docker/container.go
+++ b/plugin/docker/container.go
@@ -105,7 +105,7 @@ func (c *container) Exec(ctx context.Context, cmd string, args []string, opts pl
 	command := append([]string{cmd}, args...)
 	activity.Record(ctx, "Exec %v on %v", command, c.Name())
 
-	cfg := types.ExecConfig{Cmd: command, AttachStdout: true, AttachStderr: true, Tty: opts.Tty}
+	cfg := types.ExecConfig{Cmd: command, AttachStdout: true, AttachStderr: true, Tty: opts.Tty, WorkingDir: opts.WorkingDir}
 	if opts.Stdin != nil || opts.Tty {
 		cfg.AttachStdin = true
 	}
diff --git a/plugin/types.go b/plugin/types.go
index 859fd51a4..b698b9611 100644
--- a/plugin/types.go
+++ b/plugin/types.go
@@ -141,6 +141,9 @@ type ExecOptions struct {
 
 	// Elevate execution to run as a privileged user if not already running as a privileged user.
 	Elevate bool `json:"elevate"`
+
+	// WorkingDir is the directory in which to execute the command.
+	WorkingDir string
 }
 
 // ExecPacketType identifies the packet type.
diff --git a/volume/core.go b/volume/core.go
index 4659e1c52..d9cc697a5 100644
--- a/volume/core.go
+++ b/volume/core.go
@@ -53,7 +53,7 @@ type dirMap struct {
 // ChildSchemas returns a volume's child schema
 func ChildSchemas() []*plugin.EntrySchema {
 	return []*plugin.EntrySchema{
-		(&dir{}).Schema(),
+		(&execableDir{}).Schema(),
 		(&file{}).Schema(),
 	}
 }
@@ -66,6 +66,9 @@ const RootPath = ""
 // Requests are cached against the supplied Interface using the VolumeListCB op.
 func List(ctx context.Context, impl Interface) ([]plugin.Entry, error) {
 	// Start with the implementation as the cache key so we re-use data we get from it for subdirectory queries.
+	if exImpl, ok := impl.(execableInterface); ok {
+		return newExecDir("dummy", plugin.EntryAttributes{}, exImpl, RootPath).List(ctx)
+	}
 	return newDir("dummy", plugin.EntryAttributes{}, impl, RootPath).List(ctx)
 }
 
diff --git a/volume/execable_dir.go b/volume/execable_dir.go
new file mode 100644
index 000000000..7dafdf470
--- /dev/null
+++ b/volume/execable_dir.go
@@ -0,0 +1,59 @@
+package volume
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/puppetlabs/wash/plugin"
+)
+
+type execableInterface interface {
+	Interface
+	VolumeExec(ctx context.Context, path string, cmd string, args []string, opts plugin.ExecOptions) (plugin.ExecCommand, error)
+}
+
+// execableDir adds the exec action to dir.
+type execableDir struct {
+	dir
+	impl execableInterface
+}
+
+func newExecDir(name string, attr plugin.EntryAttributes, impl execableInterface, path string) *execableDir {
+	e := new(execableDir)
+	e.dir = *newDir(name, attr, impl, path)
+	e.impl = impl
+	return e
+}
+
+func (v *execableDir) Exec(ctx context.Context, cmd string, args []string, opts plugin.ExecOptions) (plugin.ExecCommand, error) {
+	return v.impl.VolumeExec(ctx, v.path, cmd, args, opts)
+}
+
+func (v *execableDir) generateChildren(dirmap *dirMap) []plugin.Entry {
+	entries := v.dir.generateChildren(dirmap)
+
+	for i, entry := range entries {
+		dir, ok := entry.(*dir)
+		if ok {
+			fmt.Println(dir)
+			entries[i] = &execableDir{dir: *dir, impl: v.impl}
+		}
+	}
+	return entries
+}
+
+// List lists the children of the directory.
+func (v *execableDir) List(ctx context.Context) ([]plugin.Entry, error) {
+	if v.dirmap != nil {
+		// Children have been pre-populated by a source parent.
+		return v.generateChildren(v.dirmap), nil
+	}
+
+	// Generate child hierarchy. Don't store it on this entry, but populate new dirs from it.
+	dirmap, err := v.impl.VolumeList(ctx, v.path)
+	if err != nil {
+		return nil, err
+	}
+
+	return v.generateChildren(&dirMap{mp: dirmap}), nil
+}
diff --git a/volume/fs.go b/volume/fs.go
index 16064586c..555139222 100644
--- a/volume/fs.go
+++ b/volume/fs.go
@@ -243,6 +243,12 @@ func (d *FS) loginShell() plugin.Shell {
 	return plugin.POSIXShell
 }
 
+// VolumeExec executes cmd in the directory at path.
+func (d *FS) VolumeExec(ctx context.Context, path string, cmd string, args []string, opts plugin.ExecOptions) (plugin.ExecCommand, error) {
+	opts.WorkingDir = path
+	return d.executor.Exec(ctx, cmd, args, opts)
+}
+
 const fsDescription = `
 This represents the root directory of a container/VM. It lets you navigate
 and interact with that container/VM's filesystem as if you were logged into