fix portmap envvars in docker driver

client/taskenv/env.go

@@ -730,6 +730,14 @@ func buildPortEnv(envMap map[string]string, p structs.Port, ip string, driverNet
 	}
 }
 
+func WithPortMapEnvs(envs map[string]string, ports map[string]int) map[string]string {
+	for portLabel, port := range ports {
+		portEnv := PortPrefix + portLabel
+		envs[portEnv] = strconv.Itoa(port)
+	}
+	return envs
+}
+
 // SetHostEnvvars adds the host environment variables to the tasks. The filter
 // parameter can be use to filter host environment from entering the tasks.
 func (b *Builder) SetHostEnvvars(filter []string) *Builder {

drivers/docker/driver.go

@@ -967,6 +967,7 @@ func (d *Driver) createContainerConfig(task *drivers.TaskConfig, driverConfig *T
 		logger.Debug("applied labels on the container", "labels", config.Labels)
 	}
 
+	task.Env = taskenv.WithPortMapEnvs(task.Env, driverConfig.PortMap)
 	config.Env = task.EnvList()
 
 	containerName := fmt.Sprintf("%s-%s", strings.Replace(task.Name, "/", "_", -1), task.AllocID)