From 32ade79a6273c9209dfc4c36d1df39eea73295a9 Mon Sep 17 00:00:00 2001
From: Sean Chittenden <sean@chittenden.org>
Date: Mon, 9 May 2016 00:54:33 -0700
Subject: [PATCH] cgroups are a decidedly Linux-only feature.  Build and test
 as such.

---
 client/fingerprint/cgroup.go         | 31 --------------------------
 client/fingerprint/cgroup_default.go | 10 +++++++++
 client/fingerprint/cgroup_linux.go   | 33 ++++++++++++++++++++++++++++
 3 files changed, 43 insertions(+), 31 deletions(-)

diff --git a/client/fingerprint/cgroup.go b/client/fingerprint/cgroup.go
index 3fb14a2f3..c0ec7c674 100644
--- a/client/fingerprint/cgroup.go
+++ b/client/fingerprint/cgroup.go
@@ -1,11 +1,9 @@
 package fingerprint
 
 import (
-	"fmt"
 	"log"
 	"time"
 
-	client "github.com/hashicorp/nomad/client/config"
 	"github.com/hashicorp/nomad/nomad/structs"
 )
 
@@ -47,35 +45,6 @@ func NewCGroupFingerprint(logger *log.Logger) Fingerprint {
 	return f
 }
 
-// Fingerprint tries to find a valid cgroup moint point
-func (f *CGroupFingerprint) Fingerprint(cfg *client.Config, node *structs.Node) (bool, error) {
-	mount, err := f.mountPointDetector.MountPoint()
-	if err != nil {
-		f.clearCGroupAttributes(node)
-		return false, fmt.Errorf("Failed to discover cgroup mount point: %s", err)
-	}
-
-	// Check if a cgroup mount point was found
-	if mount == "" {
-		// Clear any attributes from the previous fingerprint.
-		f.clearCGroupAttributes(node)
-
-		if f.lastState == cgroupAvailable {
-			f.logger.Printf("[INFO] fingerprint.cgroups: cgroups are unavailable")
-		}
-		f.lastState = cgroupUnavailable
-		return true, nil
-	}
-
-	node.Attributes["unique.cgroup.mountpoint"] = mount
-
-	if f.lastState == cgroupUnavailable {
-		f.logger.Printf("[INFO] fingerprint.cgroups: cgroups are available")
-	}
-	f.lastState = cgroupAvailable
-	return true, nil
-}
-
 // clearCGroupAttributes clears any node attributes related to cgroups that might
 // have been set in a previous fingerprint run.
 func (f *CGroupFingerprint) clearCGroupAttributes(n *structs.Node) {
diff --git a/client/fingerprint/cgroup_default.go b/client/fingerprint/cgroup_default.go
index eeeade435..43c55fd85 100644
--- a/client/fingerprint/cgroup_default.go
+++ b/client/fingerprint/cgroup_default.go
@@ -2,7 +2,17 @@
 
 package fingerprint
 
+import (
+	client "github.com/hashicorp/nomad/client/config"
+	"github.com/hashicorp/nomad/nomad/structs"
+)
+
 // FindCgroupMountpointDir returns an empty path on non-Linux systems
 func FindCgroupMountpointDir() (string, error) {
 	return "", nil
 }
+
+// Fingerprint tries to find a valid cgroup moint point
+func (f *CGroupFingerprint) Fingerprint(cfg *client.Config, node *structs.Node) (bool, error) {
+	return false, nil
+}
diff --git a/client/fingerprint/cgroup_linux.go b/client/fingerprint/cgroup_linux.go
index 25171c1f4..9abb959b5 100644
--- a/client/fingerprint/cgroup_linux.go
+++ b/client/fingerprint/cgroup_linux.go
@@ -3,6 +3,10 @@
 package fingerprint
 
 import (
+	"fmt"
+
+	client "github.com/hashicorp/nomad/client/config"
+	"github.com/hashicorp/nomad/nomad/structs"
 	"github.com/opencontainers/runc/libcontainer/cgroups"
 )
 
@@ -22,3 +26,32 @@ func FindCgroupMountpointDir() (string, error) {
 	}
 	return mount, nil
 }
+
+// Fingerprint tries to find a valid cgroup moint point
+func (f *CGroupFingerprint) Fingerprint(cfg *client.Config, node *structs.Node) (bool, error) {
+	mount, err := f.mountPointDetector.MountPoint()
+	if err != nil {
+		f.clearCGroupAttributes(node)
+		return false, fmt.Errorf("Failed to discover cgroup mount point: %s", err)
+	}
+
+	// Check if a cgroup mount point was found
+	if mount == "" {
+		// Clear any attributes from the previous fingerprint.
+		f.clearCGroupAttributes(node)
+
+		if f.lastState == cgroupAvailable {
+			f.logger.Printf("[INFO] fingerprint.cgroups: cgroups are unavailable")
+		}
+		f.lastState = cgroupUnavailable
+		return true, nil
+	}
+
+	node.Attributes["unique.cgroup.mountpoint"] = mount
+
+	if f.lastState == cgroupUnavailable {
+		f.logger.Printf("[INFO] fingerprint.cgroups: cgroups are available")
+	}
+	f.lastState = cgroupAvailable
+	return true, nil
+}