environs: add Environs.Config method

environs/open.go

 // Copyright 2011, 2012, 2013 Canonical Ltd.
 // Licensed under the AGPLv3, see LICENCE file for details.
 
 package environs
 
 import (
         "fmt"
         "io/ioutil"
 
         "launchpad.net/juju-core/environs/config"
         "launchpad.net/juju-core/errors"
 )
 
-var InvalidEnvironmentError error = fmt.Errorf(
-        "environment is not a juju-core environment")
+var InvalidEnvironmentError = fmt.Errorf("environment is not a juju-core environment")
 
-// Open creates a new Environ using the environment configuration with the
-// given name. If name is empty, the default environment will be used.
-func (envs *Environs) Open(name string) (Environ, error) {
-        if name == "" {
-                name = envs.Default
-                if name == "" {
-                        return nil, fmt.Errorf("no default environment found")
-                }
-        }
-        e, ok := envs.environs[name]
-        if !ok {
-                return nil, fmt.Errorf("unknown environment %q", name)
-        }
-        if e.err != nil {
-                return nil, e.err
-        }
-        return New(e.config)
-}
-
-// ConfigForName returns the configuration for the
-// environment with the given name from the default
-// environments file. If the name is blank, the default
-// environment will be used.
+// ConfigForName returns the configuration for the environment with the
+// given name from the default environments file. If the name is blank,
+// the default environment will be used. If the configuration is not
+// found, an errors.NotFoundError is returned.
 func ConfigForName(name string) (*config.Config, error) {
         envs, err := ReadEnvirons("")
         if err != nil {
                 return nil, err
         }
-        if name == "" {
-                name = envs.Default
-                if name == "" {
-                        return nil, fmt.Errorf("no default environment found")
-                }
-        }
-        e, ok := envs.environs[name]
-        if !ok {
-                return nil, fmt.Errorf("unknown environment %q", name)
-        }
-        if e.err != nil {
-                return nil, e.err
-        }
-        return e.config, nil
+        return envs.Config(name)
 }
 
 // NewFromName opens the environment with the given
 // name from the default environments file. If the
 // name is blank, the default environment will be used.
 func NewFromName(name string) (Environ, error) {
         cfg, err := ConfigForName(name)
         if err != nil {
                 return nil, err
         }
@@ skipping 56 matching lines @@
                 return nil
         } else if err != nil {
                 return err
         } else if content, err := ioutil.ReadAll(reader); err != nil {
                 return err
         } else if string(content) != verificationContent {
                 return InvalidEnvironmentError
         }
         return nil
 }