From 451b77d5d761e58d5c877b2cbbc6b97b1d2bddf1 Mon Sep 17 00:00:00 2001
From: Alex Dadgar <alex.dadgar@gmail.com>
Date: Tue, 27 Feb 2018 14:08:29 -0800
Subject: [PATCH] Unblock evals once eligible

---
 nomad/fsm.go      | 15 +++++++++++++
 nomad/fsm_test.go | 54 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+)

diff --git a/nomad/fsm.go b/nomad/fsm.go
index 7df2582db..b377f09b3 100644
--- a/nomad/fsm.go
+++ b/nomad/fsm.go
@@ -344,10 +344,25 @@ func (n *nomadFSM) applyNodeEligibilityUpdate(buf []byte, index uint64) interfac
 		panic(fmt.Errorf("failed to decode request: %v", err))
 	}
 
+	// Lookup the existing node
+	node, err := n.state.NodeByID(nil, req.NodeID)
+	if err != nil {
+		n.logger.Printf("[ERR] nomad.fsm: UpdateNodeEligibility failed to lookup node %q: %v", req.NodeID, err)
+		return err
+	}
+
 	if err := n.state.UpdateNodeEligibility(index, req.NodeID, req.Eligibility); err != nil {
 		n.logger.Printf("[ERR] nomad.fsm: UpdateNodeEligibility failed: %v", err)
 		return err
 	}
+
+	// Unblock evals for the nodes computed node class if it is in a ready
+	// state.
+	if node != nil && node.SchedulingEligibility == structs.NodeSchedulingIneligible &&
+		req.Eligibility == structs.NodeSchedulingEligible {
+		n.blockedEvals.Unblock(node.ComputedClass, index)
+	}
+
 	return nil
 }
 
diff --git a/nomad/fsm_test.go b/nomad/fsm_test.go
index b834b432f..9f8ed205a 100644
--- a/nomad/fsm_test.go
+++ b/nomad/fsm_test.go
@@ -377,6 +377,60 @@ func TestFSM_UpdateNodeEligibility(t *testing.T) {
 	require.Contains(err.Error(), "draining")
 }
 
+func TestFSM_UpdateNodeEligibility_Unblock(t *testing.T) {
+	t.Parallel()
+	require := require.New(t)
+	fsm := testFSM(t)
+
+	node := mock.Node()
+	req := structs.NodeRegisterRequest{
+		Node: node,
+	}
+	buf, err := structs.Encode(structs.NodeRegisterRequestType, req)
+	require.Nil(err)
+
+	resp := fsm.Apply(makeLog(buf))
+	require.Nil(resp)
+
+	// Set the eligibility
+	req2 := structs.NodeUpdateEligibilityRequest{
+		NodeID:      node.ID,
+		Eligibility: structs.NodeSchedulingIneligible,
+	}
+	buf, err = structs.Encode(structs.NodeUpdateEligibilityRequestType, req2)
+	require.Nil(err)
+
+	resp = fsm.Apply(makeLog(buf))
+	require.Nil(resp)
+
+	// Mark an eval as blocked.
+	eval := mock.Eval()
+	eval.ClassEligibility = map[string]bool{node.ComputedClass: true}
+	fsm.blockedEvals.Block(eval)
+
+	// Set eligible
+	req4 := structs.NodeUpdateEligibilityRequest{
+		NodeID:      node.ID,
+		Eligibility: structs.NodeSchedulingEligible,
+	}
+	buf, err = structs.Encode(structs.NodeUpdateEligibilityRequestType, req4)
+	require.Nil(err)
+
+	resp = fsm.Apply(makeLog(buf))
+	require.Nil(resp)
+
+	// Verify the eval was unblocked.
+	testutil.WaitForResult(func() (bool, error) {
+		bStats := fsm.blockedEvals.Stats()
+		if bStats.TotalBlocked != 0 {
+			return false, fmt.Errorf("bad: %#v", bStats)
+		}
+		return true, nil
+	}, func(err error) {
+		t.Fatalf("err: %s", err)
+	})
+}
+
 func TestFSM_RegisterJob(t *testing.T) {
 	t.Parallel()
 	fsm := testFSM(t)