Support environment vars in Swarm plugins services

Allow specifying environment variables when installing an engine plugin
as a Swarm service. Invalid environment variable entries (without an
equals (`=`) char) will be ignored.

Signed-off-by: Sune Keller <absukl@almbrand.dk>

api/types/swarm/runtime/plugin.proto

@@ -9,6 +9,7 @@ message PluginSpec {
 	string remote = 2;
 	repeated PluginPrivilege privileges = 3;
 	bool disabled = 4;
+	repeated string env = 5;
 }
 
 // PluginPrivilege describes a permission the user has to accept

daemon/cluster/controllers/plugin/controller.go

@@ -122,7 +122,7 @@ func (p *Controller) Prepare(ctx context.Context) (err error) {
 		return p.backend.Upgrade(ctx, remote, p.spec.Name, nil, &authConfig, privs, ioutil.Discard)
 	}
 
-	if err := p.backend.Pull(ctx, remote, p.spec.Name, nil, &authConfig, privs, ioutil.Discard, plugin.WithSwarmService(p.serviceID)); err != nil {
+	if err := p.backend.Pull(ctx, remote, p.spec.Name, nil, &authConfig, privs, ioutil.Discard, plugin.WithSwarmService(p.serviceID), plugin.WithEnv(p.spec.Env)); err != nil {
 		return err
 	}
 	pl, err = p.backend.Get(p.spec.Name)

integration/service/plugin_test.go

@@ -6,9 +6,11 @@ import (
 	"io/ioutil"
 	"os"
 	"path"
+	"strings"
 	"testing"
 
 	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/api/types/filters"
 	swarmtypes "github.com/docker/docker/api/types/swarm"
 	"github.com/docker/docker/api/types/swarm/runtime"
 	"github.com/docker/docker/integration/internal/swarm"
@@ -68,7 +70,25 @@ func TestServicePlugin(t *testing.T) {
 	poll.WaitOn(t, d2.PluginIsRunning(t, name), swarm.ServicePoll)
 	poll.WaitOn(t, d3.PluginIsRunning(t, name), swarm.ServicePoll)
 
+	// test that environment variables are passed from plugin service to plugin instance
 	service := d1.GetService(t, id)
+	tasks := d1.GetServiceTasks(t, service.Spec.Annotations.Name, filters.Arg("runtime", "plugin"))
+	if len(tasks) == 0 {
+		t.Log("No tasks found for plugin service")
+		t.Fail()
+	}
+	plugin, _, err := d1.NewClientT(t).PluginInspectWithRaw(context.Background(), name)
+	assert.NilError(t, err, "Error inspecting service plugin")
+	found := false
+	for _, env := range plugin.Settings.Env {
+		assert.Equal(t, strings.HasPrefix(env, "baz"), false, "Environment variable entry %q is invalid and should not be present", "baz")
+		if strings.HasPrefix(env, "foo=") {
+			found = true
+			assert.Equal(t, env, "foo=bar")
+		}
+	}
+	assert.Equal(t, true, found, "Environment variable %q not found in plugin", "foo")
+
 	d1.UpdateService(t, service, makePlugin(repo2, name, nil))
 	poll.WaitOn(t, d1.PluginReferenceIs(t, name, repo2), swarm.ServicePoll)
 	poll.WaitOn(t, d2.PluginReferenceIs(t, name, repo2), swarm.ServicePoll)
@@ -111,6 +131,10 @@ func makePlugin(repo, name string, constraints []string) func(*swarmtypes.Servic
 		s.Spec.TaskTemplate.PluginSpec = &runtime.PluginSpec{
 			Name:   name,
 			Remote: repo,
+			Env: []string{
+				"baz",     // invalid environment variable entries are ignored
+				"foo=bar", // "foo" will be the single environment variable
+			},
 		}
 		if constraints != nil {
 			s.Spec.TaskTemplate.Placement = &swarmtypes.Placement{

internal/test/daemon/service.go

@@ -56,7 +56,7 @@ func (d *Daemon) GetService(t assert.TestingT, id string) *swarm.Service {
 }
 
 // GetServiceTasks returns the swarm tasks for the specified service
-func (d *Daemon) GetServiceTasks(t assert.TestingT, service string) []swarm.Task {
+func (d *Daemon) GetServiceTasks(t assert.TestingT, service string, additionalFilters ...filters.KeyValuePair) []swarm.Task {
 	if ht, ok := t.(test.HelperT); ok {
 		ht.Helper()
 	}
@@ -66,6 +66,9 @@ func (d *Daemon) GetServiceTasks(t assert.TestingT, service string) []swarm.Task
 	filterArgs := filters.NewArgs()
 	filterArgs.Add("desired-state", "running")
 	filterArgs.Add("service", service)
+	for _, filter := range additionalFilters {
+		filterArgs.Add(filter.Key, filter.Value)
+	}
 
 	options := types.TaskListOptions{
 		Filters: filterArgs,

plugin/defs.go

@@ -1,6 +1,8 @@
 package plugin // import "github.com/docker/docker/plugin"
 
 import (
+	"fmt"
+	"strings"
 	"sync"
 
 	"github.com/docker/docker/pkg/plugins"
@@ -42,6 +44,31 @@ func WithSwarmService(id string) CreateOpt {
 	}
 }
 
+// WithEnv is a CreateOpt that passes the user-provided environment variables
+// to the plugin container, de-duplicating variables with the same names case
+// sensitively and only appends valid key=value pairs
+func WithEnv(env []string) CreateOpt {
+	return func(p *v2.Plugin) {
+		effectiveEnv := make(map[string]string)
+		for _, penv := range p.PluginObj.Config.Env {
+			if penv.Value != nil {
+				effectiveEnv[penv.Name] = *penv.Value
+			}
+		}
+		for _, line := range env {
+			if pair := strings.SplitN(line, "=", 2); len(pair) > 1 {
+				effectiveEnv[pair[0]] = pair[1]
+			}
+		}
+		p.PluginObj.Settings.Env = make([]string, len(effectiveEnv))
+		i := 0
+		for key, value := range effectiveEnv {
+			p.PluginObj.Settings.Env[i] = fmt.Sprintf("%s=%s", key, value)
+			i++
+		}
+	}
+}
+
 // WithSpecMounts is a SpecOpt which appends the provided mounts to the runtime spec
 func WithSpecMounts(mounts []specs.Mount) SpecOpt {
 	return func(s *specs.Spec) {