Initial distributor implementation

common/api/dm/service/v1/attempt_state_evolve.go

 // Copyright 2016 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 package dm
 
 import (
         "fmt"
 )
 
 // validAttemptStateEvolution defines all valid {From -> []To} state
 // transitions. The identity transition (X -> X) is implied, as long as X has an
 // entry in this mapping.
 var validAttemptStateEvolution = map[Attempt_State][]Attempt_State{
-        Attempt_ADDING_DEPS:              {Attempt_BLOCKED, Attempt_NEEDS_EXECUTION},
-        Attempt_BLOCKED:                  {Attempt_AWAITING_EXECUTION_STATE, Attempt_NEEDS_EXECUTION},
-        Attempt_AWAITING_EXECUTION_STATE: {Attempt_NEEDS_EXECUTION},
-        Attempt_EXECUTING:                {Attempt_ADDING_DEPS, Attempt_FINISHED},
-        Attempt_FINISHED:                 {},
-        Attempt_NEEDS_EXECUTION:          {Attempt_EXECUTING},
+        Attempt_SCHEDULING: {
+                Attempt_EXECUTING,         // scheduled
+                Attempt_ABNORMAL_FINISHED, // cancelled/timeout/err/etc.
+        },
+        Attempt_EXECUTING: {
+                Attempt_SCHEDULING,        // Retry
+                Attempt_WAITING,           // EnsureGraphData
+                Attempt_FINISHED,          // FinishAttempt
+                Attempt_ABNORMAL_FINISHED, // cancel/timeout/err/etc.
+        },
+        Attempt_WAITING: {
+                Attempt_SCHEDULING,        // unblocked
+                Attempt_ABNORMAL_FINISHED, // cancelled
+        },
+
+        Attempt_FINISHED:          {},
+        Attempt_ABNORMAL_FINISHED: {},
 }
 
 // Evolve attempts to evolve the state of this Attempt. If the state evolution
 // is not allowed (e.g. invalid state transition), this returns an error.
 func (s *Attempt_State) Evolve(newState Attempt_State) error {
         nextStates := validAttemptStateEvolution[*s]
         if nextStates == nil {
                 return fmt.Errorf("invalid state transition: no transitions defined for %s", *s)
         }
 
@@ skipping 17 matching lines @@
         if err != nil {
                 panic(err)
         }
 }
 
 // Terminal returns true iff there are no valid evolutions from the current
 // state.
 func (s Attempt_State) Terminal() bool {
         return len(validAttemptStateEvolution[s]) == 0
 }