@@ -11,7 +11,9 @@ import (

 	"github.com/docker/docker/cli"

 	"github.com/docker/docker/cli/command"

 	apiclient "github.com/docker/docker/client"

+	options "github.com/docker/docker/opts"

 	"github.com/docker/docker/pkg/promise"

+	runconfigopts "github.com/docker/docker/runconfig/opts"

 	"github.com/spf13/cobra"

 )

@@ -22,11 +24,19 @@ type execOptions struct {

 	detach      bool

 	user        string

 	privileged  bool

+	env         *options.ListOpts

+}

+

+func newExecOptions() *execOptions {

+	var values []string

+	return &execOptions{

+		env: options.NewListOptsRef(&values, runconfigopts.ValidateEnv),

+	}

 }

 // NewExecCommand creats a new cobra.Command for `docker exec`

 func NewExecCommand(dockerCli *command.DockerCli) *cobra.Command {

-	var opts execOptions

+	opts := newExecOptions()

 	cmd := &cobra.Command{

 		Use:   "exec [OPTIONS] CONTAINER COMMAND [ARG...]",

@@ -35,7 +45,7 @@ func NewExecCommand(dockerCli *command.DockerCli) *cobra.Command {

 		RunE: func(cmd *cobra.Command, args []string) error {

 			container := args[0]

 			execCmd := args[1:]

-			return runExec(dockerCli, &opts, container, execCmd)

+			return runExec(dockerCli, opts, container, execCmd)

 		},

 	}

@@ -48,6 +58,7 @@ func NewExecCommand(dockerCli *command.DockerCli) *cobra.Command {

 	flags.BoolVarP(&opts.detach, "detach", "d", false, "Detached mode: run command in the background")

 	flags.StringVarP(&opts.user, "user", "u", "", "Username or UID (format: <name|uid>[:<group|gid>])")

 	flags.BoolVarP(&opts.privileged, "privileged", "", false, "Give extended privileges to the command")

+	flags.VarP(opts.env, "env", "e", "Set environment variables")

 	return cmd

 }

@@ -188,5 +199,9 @@ func parseExec(opts *execOptions, container string, execCmd []string) (*types.Ex

 		}

 	}

+	if opts.env != nil {

+		execConfig.Env = opts.env.GetAll()

+	}

+

 	return execConfig, nil

 }

@@ -1274,7 +1274,7 @@ _docker_exec() {

 	case "$cur" in

 		-*)

-			COMPREPLY=( $( compgen -W "--detach -d --detach-keys --help --interactive -i --privileged -t --tty -u --user" -- "$cur" ) )

+			COMPREPLY=( $( compgen -W "--detach -d --detach-keys -e --env --help --interactive -i --privileged -t --tty -u --user" -- "$cur" ) )

 			;;

 		*)

 			__docker_complete_containers_running

@@ -1679,6 +1679,7 @@ __docker_subcommand() {

                 $opts_help \

                 $opts_attach_exec_run_start \

                 "($help -d --detach)"{-d,--detach}"[Detached mode: leave the container running in the background]" \

+                "($help -e --env)"{-e,--env}"[Set environment variables]" \

                 "($help -i --interactive)"{-i,--interactive}"[Keep stdin open even if not attached]" \

                 "($help)--privileged[Give extended Linux capabilities to the command]" \

                 "($help -t --tty)"{-t,--tty}"[Allocate a pseudo-tty]" \

@@ -127,7 +127,7 @@ func (d *Daemon) ContainerExecCreate(name string, config *types.ExecConfig) (str

 	if err != nil {

 		return "", err

 	}

-	execConfig.Env = utils.ReplaceOrAppendEnvValues(container.CreateDaemonEnvironment(config.Tty, linkedEnv), execConfig.Env)

+	execConfig.Env = utils.ReplaceOrAppendEnvValues(container.CreateDaemonEnvironment(config.Tty, linkedEnv), config.Env)

 	if len(execConfig.User) == 0 {

 		execConfig.User = container.Config.User

 	}

@@ -131,6 +131,7 @@ This section lists each version from latest to oldest.  Each listing includes a

 * `POST /containers/create` now takes `StopTimeout` field.

 * `POST /services/create` and `POST /services/(id or name)/update` now accept `Monitor` and `MaxFailureRatio` parameters, which control the response to failures during service updates.

 * `GET /networks/(name)` now returns `Created`.

+* `POST /containers/(id or name)/exec` now accepts an `Env` field, which holds a list of environment variables to be set in the context of the command execution.

 ### v1.24 API changes

@@ -3151,6 +3151,10 @@ Sets up an exec instance in a running container `id`

       "AttachStderr": true,

       "Cmd": ["sh"],

       "DetachKeys": "ctrl-p,ctrl-q",

+      "Env": [

+        "FOO=bar",

+        "BAZ=quux"

+      ],

       "Privileged": true,

       "Tty": true,

       "User": "123:456"

@@ -3175,6 +3179,7 @@ Sets up an exec instance in a running container `id`

         container. Format is a single character `[a-Z]` or `ctrl-<value>`

         where `<value>` is one of: `a-z`, `@`, `^`, `[`, `,` or `_`.

 -   **Tty** - Boolean value to allocate a pseudo-TTY.

+-   **Env** - A list of environment variables in the form of `["VAR=value", ...]`

 -   **Cmd** - Command to run specified as a string or an array of strings.

 -   **Privileged** - Boolean value, runs the exec process with extended privileges.

 -   **User** - A string value specifying the user, and optionally, group to run

@@ -14,6 +14,7 @@ Run a command in a running container

 Options:

   -d, --detach         Detached mode: run command in the background

       --detach-keys    Override the key sequence for detaching a container

+  -e, --env=[]         Set environment variables

       --help           Print usage

   -i, --interactive    Keep STDIN open even if not attached

       --privileged     Give extended privileges to the command

@@ -119,6 +119,17 @@ func (s *DockerSuite) TestExecEnv(c *check.C) {

 	c.Assert(out, checker.Contains, "HOME=/root")

 }

+func (s *DockerSuite) TestExecSetEnv(c *check.C) {

+	testRequires(c, DaemonIsLinux)

+	runSleepingContainer(c, "-e", "HOME=/root", "-d", "--name", "testing")

+	c.Assert(waitRun("testing"), check.IsNil)

+

+	out, _ := dockerCmd(c, "exec", "-e", "HOME=/another", "-e", "ABC=xyz", "testing", "env")

+	c.Assert(out, checker.Not(checker.Contains), "HOME=/root")

+	c.Assert(out, checker.Contains, "HOME=/another")

+	c.Assert(out, checker.Contains, "ABC=xyz")

+}

+

 func (s *DockerSuite) TestExecExitStatus(c *check.C) {

 	runSleepingContainer(c, "-d", "--name", "top")

@@ -45,7 +45,7 @@ func (clnt *client) AddProcess(ctx context.Context, containerID, processFriendly

 	sp := spec.Process

 	sp.Args = specp.Args

 	sp.Terminal = specp.Terminal

-	if specp.Env != nil {

+	if len(specp.Env) > 0 {

 		sp.Env = specp.Env

 	}

 	if specp.Cwd != nil {

@@ -8,6 +8,7 @@ docker-exec - Run a command in a running container

 **docker exec**

 [**-d**|**--detach**]

 [**--detach-keys**[=*[]*]]

+[**-e**|**--env**[=*[]*]]

 [**--help**]

 [**-i**|**--interactive**]

 [**--privileged**]

@@ -32,6 +33,12 @@ container is unpaused, and then run

 **--detach-keys**=""

   Override the key sequence for detaching a container. Format is a single character `[a-Z]` or `ctrl-<value>` where `<value>` is one of: `a-z`, `@`, `^`, `[`, `,` or `_`.

+**-e**, **--env**=[]

+   Set environment variables

+

+   This option allows you to specify arbitrary environment variables that are

+available for the command to be executed.

+

 **--help**

   Print usage statement