Implementation of the charm state.

state/state.go

 // launchpad.net/juju/state
 //
 // Copyright (c) 2011-2012 Canonical Ltd.
 
 // The state package enables reading, observing, and changing
 // the state stored in ZooKeeper of a whole environment
 // managed by juju.
 package state
 
 import (
         "fmt"
         "launchpad.net/goyaml"
         "launchpad.net/gozk/zookeeper"
+        "launchpad.net/juju/go/charm"
         "strings"
 )
 
 // State represents the state of an environment
 // managed by juju.
 type State struct {
         zk *zookeeper.Conn
 }
 
 // Add machine creates a new machine.
 func (s *State) AddMachine() (*Machine, error) {
         path, err := s.zk.Create("/machines/machine-", "", zookeeper.SEQUENCE, zkPermAll)
         if err != nil {
                 return nil, err
         }
         key := strings.Split(path, "/")[2]
         addMachine := func(t *topology) error {
                 return t.AddMachine(key)
         }
         if err = retryTopologyChange(s.zk, addMachine); err != nil {
                 return nil, err
         }
         return &Machine{s.zk, key}, nil
 }
 
+// AddCharm registers metadata about the provided Charm.
+func (s *State) AddCharm(id string, ch charm.Charm, url string) (*Charm, error) {
+        data := &charmData{
+                Meta:   ch.Meta(),
+                Config: ch.Config(),
+                SHA256: "", // Yet missing.
+                URL:    url,
+        }
+        yaml, err := goyaml.Marshal(data)
+        if err != nil {
+                return nil, err
+        }
+        _, err = s.zk.Create(charmPath(id), string(yaml), 0, zkPermAll)
+        if err != nil {
+                return nil, err
+        }
+        return newCharm(s.zk, id, data)
+}
+
+// Charm returns a charm by the given id.
+func (s *State) Charm(id string) (*Charm, error) {
+        yaml, _, err := s.zk.Get(charmPath(id))
+        if err == zookeeper.ZNONODE {
+                return nil, fmt.Errorf("charm %q not found", id)
+        } else if err != nil {

[rog, 2012/02/16 14:29:47]

no else needed here

[TheMue, 2012/02/17 14:37:21]

Done.

+                return nil, err
+        }
+        data := &charmData{}
+        if err = goyaml.Unmarshal([]byte(yaml), data); err != nil {

[rog, 2012/02/16 14:29:47]

since you can, i'd probably use err := ...
here and avoid the unnecessary reference to the
previous err variable.

[TheMue, 2012/02/17 14:37:21]

Done.

+                return nil, err
+        }
+        return newCharm(s.zk, id, data)
+}
+
 // AddService creates a new service with the given unique name
 // and the charm state.
-func (s *State) AddService(name string, charm *Charm) (*Service, error) {
-        details := map[string]interface{}{"charm": charm.URL().String()}
+func (s *State) AddService(name string, ch *Charm) (*Service, error) {
+        details := map[string]interface{}{"charm": ch.URL().String()}
         yaml, err := goyaml.Marshal(details)
         if err != nil {
                 return nil, err
         }
         path, err := s.zk.Create("/services/service-", string(yaml), zookeeper.SEQUENCE, zkPermAll)
         if err != nil {
                 return nil, err
         }
         key := strings.Split(path, "/")[2]
         service := &Service{s.zk, key, name}
@@ skipping 116 matching lines @@
         // TODO Create node for bootstrap machine.
 
         // TODO Setup default global settings information.
 
         // Finally creation of /initialized as marker.
         if _, err := s.zk.Create("/initialized", "", 0, zkPermAll); err != nil {
                 return err
         }
         return nil
 }