mdstat: Fix parsing of RAID0 lines that contain additional attributes.

We seem to have a small number of Linux servers here that have lines in
/proc/mdstat that cannot be parsed by the node exporter, due to them
containing attributes that are not matched by the regular expression
("super 1.2").

Extend the regular expression to skip this data, just like we do for all
of the other status lines.

collector/fixtures/e2e-output.txt

@@ -715,6 +715,7 @@ node_load5 0.37
 node_md_blocks{device="md0"} 248896
 node_md_blocks{device="md10"} 3.14159265e+08
 node_md_blocks{device="md11"} 4.190208e+06
+node_md_blocks{device="md12"} 3.886394368e+09
 node_md_blocks{device="md127"} 3.12319552e+08
 node_md_blocks{device="md3"} 5.853468288e+09
 node_md_blocks{device="md4"} 4.883648e+06
@@ -727,6 +728,7 @@ node_md_blocks{device="md9"} 523968
 node_md_blocks_synced{device="md0"} 248896
 node_md_blocks_synced{device="md10"} 3.14159265e+08
 node_md_blocks_synced{device="md11"} 4.190208e+06
+node_md_blocks_synced{device="md12"} 3.886394368e+09
 node_md_blocks_synced{device="md127"} 3.12319552e+08
 node_md_blocks_synced{device="md3"} 5.853468288e+09
 node_md_blocks_synced{device="md4"} 4.883648e+06
@@ -739,6 +741,7 @@ node_md_blocks_synced{device="md9"} 523968
 node_md_disks{device="md0"} 2
 node_md_disks{device="md10"} 2
 node_md_disks{device="md11"} 2
+node_md_disks{device="md12"} 2
 node_md_disks{device="md127"} 2
 node_md_disks{device="md3"} 8
 node_md_disks{device="md4"} 2
@@ -751,6 +754,7 @@ node_md_disks{device="md9"} 4
 node_md_disks_active{device="md0"} 2
 node_md_disks_active{device="md10"} 2
 node_md_disks_active{device="md11"} 2
+node_md_disks_active{device="md12"} 2
 node_md_disks_active{device="md127"} 2
 node_md_disks_active{device="md3"} 8
 node_md_disks_active{device="md4"} 2
@@ -763,6 +767,7 @@ node_md_disks_active{device="md9"} 4
 node_md_is_active{device="md0"} 1
 node_md_is_active{device="md10"} 1
 node_md_is_active{device="md11"} 1
+node_md_is_active{device="md12"} 1
 node_md_is_active{device="md127"} 1
 node_md_is_active{device="md3"} 1
 node_md_is_active{device="md4"} 0

collector/fixtures/proc/mdstat

@@ -34,4 +34,7 @@ md11 : active (auto-read-only) raid1 sdb2[0] sdc2[1]
       4190208 blocks super 1.2 [2/2] [UU]
 	resync=PENDING
 
+md12 : active raid0 sdc2[0] sdd2[1]
+      3886394368 blocks super 1.2 512k chunks
+
 unused devices: <none>

collector/mdadm_linux.go

@@ -29,7 +29,7 @@ import (
 
 var (
 	statuslineRE = regexp.MustCompile(`(\d+) blocks .*\[(\d+)/(\d+)\] \[[U_]+\]`)
-	raid0lineRE  = regexp.MustCompile(`(\d+) blocks \d+k chunks`)
+	raid0lineRE  = regexp.MustCompile(`(\d+) blocks .*\d+k chunks`)
 	buildlineRE  = regexp.MustCompile(`\((\d+)/\d+\)`)
 )
 

collector/mdadm_linux_test.go

@@ -35,6 +35,7 @@ func TestMdadm(t *testing.T) {
 		"md9":   {"md9", true, 4, 4, 523968, 523968},
 		"md10":  {"md10", true, 2, 2, 314159265, 314159265},
 		"md11":  {"md11", true, 2, 2, 4190208, 4190208},
+		"md12":  {"md12", true, 2, 2, 3886394368, 3886394368},
 	}
 
 	for _, md := range mdStates {