environs: remove VarDir global

worker/uniter/uniter.go

 package uniter
 
 import (
         "errors"
         "fmt"
         "launchpad.net/juju-core/cmd"
         "launchpad.net/juju-core/cmd/jujuc/server"
         "launchpad.net/juju-core/log"
         "launchpad.net/juju-core/state"
         "launchpad.net/juju-core/state/presence"
@@ skipping 19 matching lines @@
         service *state.Service
         hook    *hook.StateFile
         charm   *charm.Manager
         rand    *rand.Rand
         pinger  *presence.Pinger
 }
 
 // NewUniter creates a new Uniter which will install, run, and upgrade a
 // charm on behalf of the named unit, by executing hooks and operations
 // provoked by changes in st.
-func NewUniter(st *state.State, name string, varDir string) (u *Uniter, err error) {
+func NewUniter(st *state.State, name string, dataDir string) (u *Uniter, err error) {
         defer trivial.ErrorContextf(&err, "failed to create uniter for unit %q", name)
-        path, err := ensureFs(varDir, name)
+        path, err := ensureFs(dataDir, name)
         if err != nil {
                 return nil, err
         }
         unit, err := st.Unit(name)
         if err != nil {
                 return nil, err
         }
         service, err := st.Service(unit.ServiceName())
         if err != nil {
                 return nil, err
@@ skipping 139 matching lines @@
                 // TODO: commit relation state changes.
         }
         if err := u.hook.Write(hi, hook.Complete); err != nil {
                 return err
         }
         log.Printf("hook complete")
         return nil
 }
 
 // ensureFs ensures that files and directories required by the named uniter
-// exist inside varDir. It returns the path to the directory within which the uniter must
+// exist inside dataDir. It returns the path to the directory within which the uniter must
 // store its data.
-func ensureFs(varDir, name string) (string, error) {
+func ensureFs(dataDir, name string) (string, error) {
         // TODO: do this OAOO at packaging time?
-        if err := EnsureJujucSymlinks(varDir, name); err != nil {
+        if err := EnsureJujucSymlinks(dataDir, name); err != nil {
                 return "", err
         }
-        path := filepath.Join(varDir, "units", strings.Replace(name, "/", "-", 1))
+        path := filepath.Join(dataDir, "units", strings.Replace(name, "/", "-", 1))
         if err := trivial.EnsureDir(filepath.Join(path, "state")); err != nil {
                 return "", err
         }
         return path, nil
 }