Add State method to juju.Conn

juju/conn.go

 package juju
 
 import (
         "launchpad.net/juju/go/environs"
         "launchpad.net/juju/go/state"
         "regexp"
+        "sync"
 )
 
 var (
         ValidService = regexp.MustCompile("^[a-z][a-z0-9]*(-[a-z0-9]*[a-z][a-z0-9]*)*$")
         ValidUnit    = regexp.MustCompile("^[a-z][a-z0-9]*(-[a-z0-9]*[a-z][a-z0-9]*)*/[0-9]+$")
 )
 
 // Conn holds a connection to a juju.
 type Conn struct {
         Environ environs.Environ
         state   *state.State
+        mu      sync.Mutex
 }
 
 // NewConn returns a Conn pointing at the environName environment, or the
 // default environment if not specified.
 func NewConn(environName string) (*Conn, error) {
         environs, err := environs.ReadEnvirons("")
         if err != nil {
                 return nil, err
         }
         environ, err := environs.Open(environName)
         if err != nil {
                 return nil, err
         }
         return &Conn{Environ: environ}, nil
 }
 
 // Bootstrap initializes the Conn's environment and makes it ready to deploy
 // services.
 func (c *Conn) Bootstrap(uploadTools bool) error {
         return c.Environ.Bootstrap(uploadTools)
 }
 
 // Destroy destroys the Conn's environment and all its instances.
 func (c *Conn) Destroy() error {
         return c.Environ.Destroy(nil)
 }
 
 // State returns the conn's State.
 func (c *Conn) State() (*state.State, error) {
+        c.mu.Lock()
+        defer c.mu.Unlock()
         if c.state == nil {
                 info, err := c.Environ.StateInfo()
                 if err != nil {
                         return nil, err
                 }
                 st, err := state.Open(info)
                 if err != nil {
                         return nil, err
                 }
                 c.state = st
         }
         return c.state, nil
 }