Issue with Regex and NORRDDISKS Setting

6 messages in this thread

list Matt Vander Werf · Wed, 2 Mar 2016 11:31:33 -0500 ·

Hello,

Looking at past list e-mails, it is my understanding that the NORRDDISKS
setting in xymonserver.cfg allows for PCRE regular expressions. Is this
correct? Or does it only allow certain PCRE regular expressions, but not
everything?

I ask because I'm experiencing an issue with my NORRDDISKS setting.

I'd like to ignore disks for graphing that have mount points "/tmp", but
not ignore disks with mount points that have "tmp" in them, like
"/tmpscratch".

I noticed that for other disk mount point names that if you just use
"^/<name>" with no modifiers, then it only ignores disk mount points with
only exactly "^/<name>" and not "^/<name><additional text>" or
"^/<name>/<more name>" (at least from what I can tell).

For example when using:

NORRDDISKS="^/dev|^/tmp|^/var"

It ignores disks with mount points "/dev" and "/var", but also "/tmp" AND
"/tmpscratch". But it doesn't look like it ignores "/var/tmp" (at least as
far as I can tell).

I tried using "^/tmp$" and that didn't work either (still ignored both
names).


Any idea what's going on here? Or how this can be done correctly? Is the
"$" metacharacter not allowed in this setting?


If it's needed, I'm running the latest 4.3.26-1 Terabithia RPM on RHEL 7.

Thanks for any help!!

--
Matt Vander Werf

list Japheth Cleaver · Wed, 2 Mar 2016 08:50:50 -0800 ·

▸ quoted from Matt Vander Werf


On Wed, March 2, 2016 8:31 am, Matt Vander Werf wrote:

Hello,

Looking at past list e-mails, it is my understanding that the NORRDDISKS
setting in xymonserver.cfg allows for PCRE regular expressions. Is this
correct? Or does it only allow certain PCRE regular expressions, but not
everything?

I ask because I'm experiencing an issue with my NORRDDISKS setting.

I'd like to ignore disks for graphing that have mount points "/tmp", but
not ignore disks with mount points that have "tmp" in them, like
"/tmpscratch".

I noticed that for other disk mount point names that if you just use
"^/<name>" with no modifiers, then it only ignores disk mount points with
only exactly "^/<name>" and not "^/<name><additional text>" or
"^/<name>/<more name>" (at least from what I can tell).

For example when using:

NORRDDISKS="^/dev|^/tmp|^/var"

It ignores disks with mount points "/dev" and "/var", but also "/tmp" AND
"/tmpscratch". But it doesn't look like it ignores "/var/tmp" (at least as
far as I can tell).

I tried using "^/tmp$" and that didn't work either (still ignored both
names).


Any idea what's going on here? Or how this can be done correctly? Is the
"$" metacharacter not allowed in this setting?


If it's needed, I'm running the latest 4.3.26-1 Terabithia RPM on RHEL 7.

Thanks for any help!!

--
Matt Vander Werf


Try checking the output of 'xymoncmd env | grep NORRD' ? If the '$' is not
coming through, it might be getting read in as an attempt at a shell
variable.

If so, can you try escaping it as \$ instead?

Alternatively: '^(/dev|/tmp|/var)$'


HTH,
-jc

list Matt Vander Werf · Wed, 2 Mar 2016 14:23:15 -0500 ·

Hi J.C.,

It doesn't seem to be working with or without the escape backslash. It
doesn't show up in the env output either way.

root@<host> ~]# grep NORRDDISK /etc/xymon/xymonserver.cfg
NORRDDISKS="^/dev|^/var|^/tmp$"
[root@<host> ~]# xymoncmd env | grep NORRD
2016-03-02 14:18:47.151545 xgetenv: Cannot find value for variable
NORRDDISKS=^/dev|^/var|^/tmp

[root@<host> ~]# grep NORRDDISK /etc/xymon/xymonserver.cfg
NORRDDISKS="^/dev|^/var|^/tmp\$"
[root@<host> ~]# xymoncmd env | grep NORRD
2016-03-02 14:17:47.233910 xgetenv: Cannot find value for variable
NORRDDISKS=^/dev|^/var|^/tmp


When I do it with them grouped together, it gives me the same result:

[root@<host> ~]# grep NORRDDISK /etc/xymon/xymonserver.cfg
NORRDDISKS="^(/dev|/var|/tmp)$"
[root@<host> ~]# xymoncmd env | grep NORRD
2016-03-02 14:20:35.984507 xgetenv: Cannot find value for variable
NORRDDISKS=^(/dev|/var|/tmp)

Any ideas?

Thanks!!

--
Matt Vander Werf

On Wed, Mar 2, 2016 at 11:50 AM, J.C. Cleaver <user-87556346d4af@xymon.invalid>

▸ quoted from Japheth Cleaver

wrote:

On Wed, March 2, 2016 8:31 am, Matt Vander Werf wrote:

Hello,

Looking at past list e-mails, it is my understanding that the NORRDDISKS
setting in xymonserver.cfg allows for PCRE regular expressions. Is this
correct? Or does it only allow certain PCRE regular expressions, but not
everything?

I ask because I'm experiencing an issue with my NORRDDISKS setting.

I'd like to ignore disks for graphing that have mount points "/tmp", but
not ignore disks with mount points that have "tmp" in them, like
"/tmpscratch".

I noticed that for other disk mount point names that if you just use
"^/<name>" with no modifiers, then it only ignores disk mount points with
only exactly "^/<name>" and not "^/<name><additional text>" or
"^/<name>/<more name>" (at least from what I can tell).

For example when using:

NORRDDISKS="^/dev|^/tmp|^/var"

It ignores disks with mount points "/dev" and "/var", but also "/tmp" AND
"/tmpscratch". But it doesn't look like it ignores "/var/tmp" (at least
as
far as I can tell).

I tried using "^/tmp$" and that didn't work either (still ignored both
names).


Any idea what's going on here? Or how this can be done correctly? Is the
"$" metacharacter not allowed in this setting?


If it's needed, I'm running the latest 4.3.26-1 Terabithia RPM on RHEL 7.

Thanks for any help!!

--
Matt Vander Werf


Try checking the output of 'xymoncmd env | grep NORRD' ? If the '$' is not
coming through, it might be getting read in as an attempt at a shell
variable.

If so, can you try escaping it as \$ instead?

Alternatively: '^(/dev|/tmp|/var)$'


HTH,
-jc

list Japheth Cleaver · Wed, 2 Mar 2016 12:06:17 -0800 ·

Hmm. Taking a look at the code, there's not really a provision for
escaping in this manner. And unfortunately, this is parsed in various
places throughout xymonlaunch (and passed onto the shell).

The only workaround that seems to work properly is substitution prior to
xymoncmd's reading:

in xymonserver.cfg:
NORRDDISKS='^(/dev|/tmp|/var)$FOO'

then run:
env FOO='$' xymoncmd env | grep NORRD


You could either place FOO='$' in a shell wrapper launched from tasks.cfg,
or stick it way up in /etc/sysconfig/xymonlaunch (if you're using the
RPM).

I'm tempted to try a patch allowing '$$' to mean an unprocessed '$', but
that might interfere with people who want a shell PID for some reason.
Alternatively, adding '\' escaping globally in environment files might
cause other sorts of problems for folks.


Alternatively-alternatively, NORRDDISKS='^(/dev|/tmp|/var)\Z' might work
for you, since this *is* just straight PCRE...


-jc

▸ quoted from Matt Vander Werf



On Wed, March 2, 2016 11:23 am, Matt Vander Werf wrote:

Hi J.C.,

It doesn't seem to be working with or without the escape backslash. It
doesn't show up in the env output either way.

root@<host> ~]# grep NORRDDISK /etc/xymon/xymonserver.cfg
NORRDDISKS="^/dev|^/var|^/tmp$"
[root@<host> ~]# xymoncmd env | grep NORRD
2016-03-02 14:18:47.151545 xgetenv: Cannot find value for variable
NORRDDISKS=^/dev|^/var|^/tmp

[root@<host> ~]# grep NORRDDISK /etc/xymon/xymonserver.cfg
NORRDDISKS="^/dev|^/var|^/tmp\$"
[root@<host> ~]# xymoncmd env | grep NORRD
2016-03-02 14:17:47.233910 xgetenv: Cannot find value for variable
NORRDDISKS=^/dev|^/var|^/tmp


When I do it with them grouped together, it gives me the same result:

[root@<host> ~]# grep NORRDDISK /etc/xymon/xymonserver.cfg
NORRDDISKS="^(/dev|/var|/tmp)$"
[root@<host> ~]# xymoncmd env | grep NORRD
2016-03-02 14:20:35.984507 xgetenv: Cannot find value for variable
NORRDDISKS=^(/dev|/var|/tmp)

Any ideas?

Thanks!!

--
Matt Vander Werf

On Wed, Mar 2, 2016 at 11:50 AM, J.C. Cleaver <user-87556346d4af@xymon.invalid>
wrote:

On Wed, March 2, 2016 8:31 am, Matt Vander Werf wrote:

Hello,

Looking at past list e-mails, it is my understanding that the

NORRDDISKS

setting in xymonserver.cfg allows for PCRE regular expressions. Is
this
correct? Or does it only allow certain PCRE regular expressions, but
not
everything?

I ask because I'm experiencing an issue with my NORRDDISKS setting.

I'd like to ignore disks for graphing that have mount points "/tmp",
but
not ignore disks with mount points that have "tmp" in them, like
"/tmpscratch".

I noticed that for other disk mount point names that if you just use
"^/<name>" with no modifiers, then it only ignores disk mount points
with
only exactly "^/<name>" and not "^/<name><additional text>" or
"^/<name>/<more name>" (at least from what I can tell).

For example when using:

NORRDDISKS="^/dev|^/tmp|^/var"

It ignores disks with mount points "/dev" and "/var", but also "/tmp"

AND

"/tmpscratch". But it doesn't look like it ignores "/var/tmp" (at
least
as
far as I can tell).

I tried using "^/tmp$" and that didn't work either (still ignored both
names).


Any idea what's going on here? Or how this can be done correctly? Is
the
"$" metacharacter not allowed in this setting?


If it's needed, I'm running the latest 4.3.26-1 Terabithia RPM on RHEL

7.

Thanks for any help!!

--
Matt Vander Werf


Try checking the output of 'xymoncmd env | grep NORRD' ? If the '$' is
not
coming through, it might be getting read in as an attempt at a shell
variable.

If so, can you try escaping it as \$ instead?

Alternatively: '^(/dev|/tmp|/var)$'


HTH,
-jc

list Matt Vander Werf · Wed, 2 Mar 2016 16:01:33 -0500 ·

Hi J.C.,

Adding the '\Z' instead of '$' doesn't seem to work either.

[root@<host> ~]# xymoncmd env | grep NORRD
NORRDDISKS=^/dev|^/var|^/tmpZ


How would I do that shell wrapper launched from tasks.cfg?

I tried to stick it in /etc/sysconfig/xymonlaunch and it came back with an
error message "Ignoring invalid environment assignment 'env FOO=$':
/etc/sysconfig/xymonlaunch" and "xymoncmd[15102]: 2016-03-02
15:55:16.622168 xgetenv: Cannot find value for variable FOO".

Just putting in FOO='$' without the 'env' didn't work either.


Thanks for your help!!

▸ quoted from Japheth Cleaver


--
Matt Vander Werf

On Wed, Mar 2, 2016 at 3:06 PM, J.C. Cleaver <user-87556346d4af@xymon.invalid> wrote:

Hmm. Taking a look at the code, there's not really a provision for
escaping in this manner. And unfortunately, this is parsed in various
places throughout xymonlaunch (and passed onto the shell).

The only workaround that seems to work properly is substitution prior to
xymoncmd's reading:

in xymonserver.cfg:
NORRDDISKS='^(/dev|/tmp|/var)$FOO'

then run:
env FOO='$' xymoncmd env | grep NORRD


You could either place FOO='$' in a shell wrapper launched from tasks.cfg,
or stick it way up in /etc/sysconfig/xymonlaunch (if you're using the
RPM).

I'm tempted to try a patch allowing '$$' to mean an unprocessed '$', but
that might interfere with people who want a shell PID for some reason.
Alternatively, adding '\' escaping globally in environment files might
cause other sorts of problems for folks.


Alternatively-alternatively, NORRDDISKS='^(/dev|/tmp|/var)\Z' might work
for you, since this *is* just straight PCRE...


-jc


On Wed, March 2, 2016 11:23 am, Matt Vander Werf wrote:

Hi J.C.,

It doesn't seem to be working with or without the escape backslash. It
doesn't show up in the env output either way.

root@<host> ~]# grep NORRDDISK /etc/xymon/xymonserver.cfg
NORRDDISKS="^/dev|^/var|^/tmp$"
[root@<host> ~]# xymoncmd env | grep NORRD
2016-03-02 14:18:47.151545 xgetenv: Cannot find value for variable
NORRDDISKS=^/dev|^/var|^/tmp

[root@<host> ~]# grep NORRDDISK /etc/xymon/xymonserver.cfg
NORRDDISKS="^/dev|^/var|^/tmp\$"
[root@<host> ~]# xymoncmd env | grep NORRD
2016-03-02 14:17:47.233910 xgetenv: Cannot find value for variable
NORRDDISKS=^/dev|^/var|^/tmp


When I do it with them grouped together, it gives me the same result:

[root@<host> ~]# grep NORRDDISK /etc/xymon/xymonserver.cfg
NORRDDISKS="^(/dev|/var|/tmp)$"
[root@<host> ~]# xymoncmd env | grep NORRD
2016-03-02 14:20:35.984507 xgetenv: Cannot find value for variable
NORRDDISKS=^(/dev|/var|/tmp)

Any ideas?

Thanks!!

--
Matt Vander Werf

On Wed, Mar 2, 2016 at 11:50 AM, J.C. Cleaver <user-87556346d4af@xymon.invalid>
wrote:

On Wed, March 2, 2016 8:31 am, Matt Vander Werf wrote:

Hello,

Looking at past list e-mails, it is my understanding that the

NORRDDISKS

setting in xymonserver.cfg allows for PCRE regular expressions. Is
this
correct? Or does it only allow certain PCRE regular expressions, but
not
everything?

I ask because I'm experiencing an issue with my NORRDDISKS setting.

I'd like to ignore disks for graphing that have mount points "/tmp",
but
not ignore disks with mount points that have "tmp" in them, like
"/tmpscratch".

I noticed that for other disk mount point names that if you just use
"^/<name>" with no modifiers, then it only ignores disk mount points
with
only exactly "^/<name>" and not "^/<name><additional text>" or
"^/<name>/<more name>" (at least from what I can tell).

For example when using:

NORRDDISKS="^/dev|^/tmp|^/var"

It ignores disks with mount points "/dev" and "/var", but also "/tmp"

AND

"/tmpscratch". But it doesn't look like it ignores "/var/tmp" (at
least
as
far as I can tell).

I tried using "^/tmp$" and that didn't work either (still ignored both
names).


Any idea what's going on here? Or how this can be done correctly? Is
the
"$" metacharacter not allowed in this setting?


If it's needed, I'm running the latest 4.3.26-1 Terabithia RPM on RHEL

7.

Thanks for any help!!

--
Matt Vander Werf


Try checking the output of 'xymoncmd env | grep NORRD' ? If the '$' is
not
coming through, it might be getting read in as an attempt at a shell
variable.

If so, can you try escaping it as \$ instead?

Alternatively: '^(/dev|/tmp|/var)$'


HTH,
-jc

list Japheth Cleaver · Wed, 2 Mar 2016 13:32:05 -0800 ·

The 'env' would be unnecessary, however I just realized that you're
running on EL7. systemd strikes again, unfortunately...

The shell wrapper shim is the easiest solution

Create a chmod 755 file /tmp/blah:
====
#!/bin/sh

NORRDDISKS='^(/dev|/tmp|/var)$'
export NORRDDISKS

exec $*
====

Then edit your xymond_rrd CMD line from something like:
   CMD xymond_channel --channel=data xymond_rrd --rrddir=$XYMONVAR/rrd
to
   CMD xymond_channel --channel=data /tmp/blah xymond_rrd
--rrddir=$XYMONVAR/rrd

(same for 'status').

That *should* set it properly. You can remove it from the normal
xymonserver.cfg file if you like.

This is definitely a complete hack, but I'm not sure what the best
long-term fix is, like I said.


HTH,

▸ quoted from Matt Vander Werf


-jc


On Wed, March 2, 2016 1:01 pm, Matt Vander Werf wrote:

Hi J.C.,

Adding the '\Z' instead of '$' doesn't seem to work either.

[root@<host> ~]# xymoncmd env | grep NORRD
NORRDDISKS=^/dev|^/var|^/tmpZ


How would I do that shell wrapper launched from tasks.cfg?

I tried to stick it in /etc/sysconfig/xymonlaunch and it came back with an
error message "Ignoring invalid environment assignment 'env FOO=$':
/etc/sysconfig/xymonlaunch" and "xymoncmd[15102]: 2016-03-02
15:55:16.622168 xgetenv: Cannot find value for variable FOO".

Just putting in FOO='$' without the 'env' didn't work either.


Thanks for your help!!

--
Matt Vander Werf

On Wed, Mar 2, 2016 at 3:06 PM, J.C. Cleaver <user-87556346d4af@xymon.invalid>
wrote:

Hmm. Taking a look at the code, there's not really a provision for
escaping in this manner. And unfortunately, this is parsed in various
places throughout xymonlaunch (and passed onto the shell).

The only workaround that seems to work properly is substitution prior to
xymoncmd's reading:

in xymonserver.cfg:
NORRDDISKS='^(/dev|/tmp|/var)$FOO'

then run:
env FOO='$' xymoncmd env | grep NORRD


You could either place FOO='$' in a shell wrapper launched from
tasks.cfg,
or stick it way up in /etc/sysconfig/xymonlaunch (if you're using the
RPM).

I'm tempted to try a patch allowing '$$' to mean an unprocessed '$', but
that might interfere with people who want a shell PID for some reason.
Alternatively, adding '\' escaping globally in environment files might
cause other sorts of problems for folks.


Alternatively-alternatively, NORRDDISKS='^(/dev|/tmp|/var)\Z' might work
for you, since this *is* just straight PCRE...


-jc


On Wed, March 2, 2016 11:23 am, Matt Vander Werf wrote:

Hi J.C.,

It doesn't seem to be working with or without the escape backslash. It
doesn't show up in the env output either way.

root@<host> ~]# grep NORRDDISK /etc/xymon/xymonserver.cfg
NORRDDISKS="^/dev|^/var|^/tmp$"
[root@<host> ~]# xymoncmd env | grep NORRD
2016-03-02 14:18:47.151545 xgetenv: Cannot find value for variable
NORRDDISKS=^/dev|^/var|^/tmp

[root@<host> ~]# grep NORRDDISK /etc/xymon/xymonserver.cfg
NORRDDISKS="^/dev|^/var|^/tmp\$"
[root@<host> ~]# xymoncmd env | grep NORRD
2016-03-02 14:17:47.233910 xgetenv: Cannot find value for variable
NORRDDISKS=^/dev|^/var|^/tmp


When I do it with them grouped together, it gives me the same result:

[root@<host> ~]# grep NORRDDISK /etc/xymon/xymonserver.cfg
NORRDDISKS="^(/dev|/var|/tmp)$"
[root@<host> ~]# xymoncmd env | grep NORRD
2016-03-02 14:20:35.984507 xgetenv: Cannot find value for variable
NORRDDISKS=^(/dev|/var|/tmp)

Any ideas?

Thanks!!

--
Matt Vander Werf

On Wed, Mar 2, 2016 at 11:50 AM, J.C. Cleaver <user-87556346d4af@xymon.invalid>
wrote:

On Wed, March 2, 2016 8:31 am, Matt Vander Werf wrote:

Hello,

Looking at past list e-mails, it is my understanding that the

NORRDDISKS

setting in xymonserver.cfg allows for PCRE regular expressions. Is
this
correct? Or does it only allow certain PCRE regular expressions,
but
not
everything?

I ask because I'm experiencing an issue with my NORRDDISKS setting.

I'd like to ignore disks for graphing that have mount points

"/tmp",

but

not ignore disks with mount points that have "tmp" in them, like
"/tmpscratch".

I noticed that for other disk mount point names that if you just
use
"^/<name>" with no modifiers, then it only ignores disk mount
points
with
only exactly "^/<name>" and not "^/<name><additional text>" or
"^/<name>/<more name>" (at least from what I can tell).

For example when using:

NORRDDISKS="^/dev|^/tmp|^/var"

It ignores disks with mount points "/dev" and "/var", but also

"/tmp"

AND

"/tmpscratch". But it doesn't look like it ignores "/var/tmp" (at
least
as
far as I can tell).

I tried using "^/tmp$" and that didn't work either (still ignored
both
names).


Any idea what's going on here? Or how this can be done correctly?

Is

the

"$" metacharacter not allowed in this setting?


If it's needed, I'm running the latest 4.3.26-1 Terabithia RPM on

RHEL

7.

Thanks for any help!!

--
Matt Vander Werf


Try checking the output of 'xymoncmd env | grep NORRD' ? If the '$'
is
not
coming through, it might be getting read in as an attempt at a shell
variable.

If so, can you try escaping it as \$ instead?

Alternatively: '^(/dev|/tmp|/var)$'


HTH,
-jc

Issue with Regex and NORRDDISKS Setting 🔗 link

Issue with Regex and NORRDDISKS Setting