On cli node status list print the short Node ID when possible

command/node_status.go

@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"sort"
 	"strings"
+
+	"github.com/hashicorp/nomad/api"
 )
 
 type NodeStatusCommand struct {
@@ -78,12 +80,14 @@ func (c *NodeStatusCommand) Run(args []string) int {
 			return 0
 		}
 
+		shortenNodeId := shouldShortenNodeIds(nodes)
+
 		// Format the nodes list
 		out := make([]string, len(nodes)+1)
 		out[0] = "ID|DC|Name|Class|Drain|Status"
 		for i, node := range nodes {
 			out[i+1] = fmt.Sprintf("%s|%s|%s|%s|%v|%s",
-				node.ID,
+				shortenId(node.ID, shortenNodeId),
 				node.Datacenter,
 				node.Name,
 				node.NodeClass,
@@ -160,3 +164,27 @@ func (c *NodeStatusCommand) Run(args []string) int {
 	}
 	return 0
 }
+
+// check if there is a collision if we shorten the Node ids
+func shouldShortenNodeIds(nodes []*api.NodeListStub) bool {
+	ids := map[string]bool{}
+
+	for _, node := range nodes {
+		if len(node.ID) != 36 {
+			return false //We have a custom ID, don't shorten anything
+		} else if ids[node.ID[:8]] == true {
+			return false //There is a collision
+		} else {
+			ids[node.ID[:8]] = true
+		}
+	}
+	return true
+}
+
+// shorten an UUID syntax XXXXXXXX-XX... to 8 chars XXXXXXXX
+func shortenId(id string, shouldShortenId bool) string {
+	if shouldShortenId == true {
+		return id[:8]
+	}
+	return id
+}

command/node_status_test.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/hashicorp/nomad/api"
 	"github.com/hashicorp/nomad/testutil"
 	"github.com/mitchellh/cli"
 )
@@ -108,3 +109,47 @@ func TestNodeStatusCommand_Fails(t *testing.T) {
 		t.Fatalf("expected not found error, got: %s", out)
 	}
 }
+
+func Test_ShortenId(t *testing.T) {
+	id := "1234567890"
+	shortID := "12345678"
+
+	dontShorten := shortenId(id, false)
+	if dontShorten != id {
+		t.Fatalf("Shorten ID should not short id on false, expected %s, got: %s", id, dontShorten)
+	}
+
+	shorten := shortenId(id, true)
+	if shorten != shortID {
+		t.Fatalf("Shorten ID should short id on true, expected %s, got: %s", shortID, shorten)
+	}
+}
+
+func Test_ShouldShortenNodeIds(t *testing.T) {
+	var list []*api.NodeListStub
+	nodeCustomId := &api.NodeListStub{
+		ID: "my_own_id",
+	}
+	nodeOne := &api.NodeListStub{
+		ID: "11111111-1111-1111-1111-111111111111",
+	}
+	nodeTwo := &api.NodeListStub{
+		ID: "11111111-2222-2222-2222-222222222222",
+	}
+
+	list = append(list, nodeCustomId)
+	if shouldShortenNodeIds(list) != false {
+		t.Fatalf("ShouldShortenNodeIds should return false when using custom id")
+	}
+
+	list = nil
+	list = append(list, nodeOne)
+	if shouldShortenNodeIds(list) != true {
+		t.Fatalf("ShouldShortenNodeIds should return true when no collisions")
+	}
+
+	list = append(list, nodeTwo)
+	if shouldShortenNodeIds(list) != false {
+		t.Fatalf("ShouldShortenNodeIds should return false when collision detected")
+	}
+}