// Write atomically writes to disk the relation state change in hi.
// It must be called after the respective hook was executed successfully.
// Write doesn't validate hi but guarantees that successive writes of
// the same hi are idempotent.
func (d *StateDir) Write(hi hook.Info) (err error) {
defer trivial.ErrorContextf(&err, "failed to write %q hook info for %q on state directory", hi.Kind, hi.RemoteUnit)
if hi.Kind == hook.RelationBroken {
return d.Remove()
}
name := strings.Replace(hi.RemoteUnit, "/", "-", 1)
path := filepath.Join(d.path, name)
if hi.Kind == hook.RelationDeparted {
if err = os.Remove(path); err != nil && !os.IsNotExist(err) {
return err
}
// If atomic delete succeeded, update own state.
delete(d.state.Members, hi.RemoteUnit)
return nil
}
di := diskInfo{&hi.ChangeVersion, hi.Kind == hook.RelationJoined}
if err := trivial.WriteYaml(path, &di); err != nil {
return err
}
// If write was successful, update own state.
d.state.Members[hi.RemoteUnit] = hi.ChangeVersion
if hi.Kind == hook.RelationJoined {
d.state.ChangedPending = hi.RemoteUnit
} else {
d.state.ChangedPending = ""
}
return nil
}
func (s *StateFileSuite) TestStates(c *C) {
for i, t := range stateTests {
c.Logf("test %d", i)
path := filepath.Join(c.MkDir(), "uniter")
file := uniter.NewStateFile(path)
_, err := file.Read()
c.Assert(err, Equals, uniter.ErrNoStateFile)
write := func() {
err := file.Write(t.st.Started, t.st.Op, t.st.OpStep, t.st.Hook, t.st.CharmURL)
c.Assert(err, IsNil)
}
if t.err != "" {
c.Assert(write, PanicMatches, "invalid uniter state: "+t.err)
err := trivial.WriteYaml(path, &t.st)
c.Assert(err, IsNil)
_, err = file.Read()
c.Assert(err, ErrorMatches, "cannot read charm state at .*: invalid uniter state: "+t.err)
continue
}
write()
st, err := file.Read()
c.Assert(err, IsNil)
if st.Hook != nil {
c.Assert(st.Hook.Members, HasLen, 0)
st.Hook.Members = t.st.Hook.Members
}
c.Assert(*st, DeepEquals, t.st)
}
}
// Write stores the supplied state to the file.
func (f *StateFile) Write(started bool, op Op, step OpStep, hi *hook.Info, url *charm.URL) error {
if hi != nil {
// Strip membership info: it's potentially large, and can
// be reconstructed from relation state when required.
hiCopy := *hi
hiCopy.Members = nil
hi = &hiCopy
}
st := &State{
Started: started,
Op: op,
OpStep: step,
Hook: hi,
CharmURL: url,
}
if err := st.validate(); err != nil {
panic(err)
}
return trivial.WriteYaml(f.path, st)
}
// WriteCharmURL writes a charm identity file into the directory.
func WriteCharmURL(d *GitDir, url *charm.URL) error {
return trivial.WriteYaml(filepath.Join(d.path, ".juju-charm"), url.String())
}