[libvirt] [PATCH] virt-xml-validate: Allow input to be read from stdin
--- Hello, I often find myself wanting to validate a domain xml without having to save it to a file, so I've updated virt-xml-validate to support the standard practice of reading from stdin when "-" is given as the input file. Of course, the validation is multipass so there still needs to be a temporary file but I think it makes sense to hide this complexity in virt-xml-validate and not force it onto the user. /Johannes tools/virt-xml-validate.in | 53 +++++++++++++++++++++++++++++++++------------- 1 file changed, 38 insertions(+), 15 deletions(-) diff --git a/tools/virt-xml-validate.in b/tools/virt-xml-validate.in index a04fa06..8807f8d 100644 --- a/tools/virt-xml-validate.in +++ b/tools/virt-xml-validate.in @@ -17,6 +17,16 @@ set -e +TMPFILE= + +cleanup() { + if [ $TMPFILE ]; then + rm -f $TMPFILE + fi +} + +trap cleanup EXIT + case $1 in -h | --h | --he | --hel | --help) cat <<EOF @@ -35,7 +45,7 @@ $0 (libvirt) @VERSION@ EOF exit ;; --) shift ;; - -*) + -?*) echo "$0: unrecognized option '$1'" >&2 exit 1 ;; esac @@ -43,18 +53,27 @@ esac XMLFILE="$1" TYPE="$2" -if [ -z "$XMLFILE" ]; then - echo "syntax: $0 XMLFILE [TYPE]" >&2 - exit 1 -fi - -if [ ! -f "$XMLFILE" ]; then - echo "$0: document $XMLFILE does not exist" >&2 - exit 2 +if [ "$XMLFILE" = "-" ]; then + TMPFILE=`mktemp --tmpdir virt-xml.XXXX` + cat > $TMPFILE +else + if [ -z "$XMLFILE" ]; then + echo "syntax: $0 XMLFILE [TYPE]" >&2 + exit 1 + fi + + if [ ! -f "$XMLFILE" ]; then + echo "$0: document $XMLFILE does not exist" >&2 + exit 2 + fi fi if [ -z "$TYPE" ]; then - ROOT=`xmllint --stream --debug "$XMLFILE" 2>/dev/null | grep "^0 1 " | awk '{ print $3 }'` + if [ $TMPFILE ]; then + ROOT=`cat "$TMPFILE" | xmllint --stream --debug - 2>/dev/null | grep "^0 1 " | awk '{ print $3 }'` + else + ROOT=`xmllint --stream --debug "$XMLFILE" 2>/dev/null | grep "^0 1 " | awk '{ print $3 }'` + fi case "$ROOT" in *domainsnapshot*) # Must come first, since *domain* is a substring TYPE="domainsnapshot" @@ -99,8 +118,11 @@ if [ ! -f "$SCHEMA" ]; then exit 4 fi -xmllint --noout --relaxng "$SCHEMA" "$XMLFILE" - +if [ $TMPFILE ]; then + cat "$TMPFILE" | xmllint --noout --relaxng "$SCHEMA" - +else + xmllint --noout --relaxng "$SCHEMA" "$XMLFILE" +fi exit : <<=cut @@ -119,9 +141,10 @@ exit Validates a libvirt XML for compliance with the published schema. The first compulsory argument is the path to the XML file to be -validated. The optional second argument is the name of the schema -to validate against. If omitted, the schema name will be inferred -from the name of the root element in the XML document. +validated (or - to read the XML from standard input). The optional +second argument is the name of the schema to validate against. If +omitted, the schema name will be inferred from the name of the root +element in the XML document. Valid schema names currently include -- 1.9.1
On Wed, Jun 10, 2015 at 12:03:44PM +0200, Johannes Holmberg wrote:
---
Hello,
I often find myself wanting to validate a domain xml without having to save it to a file, so I've updated virt-xml-validate to support the standard practice of reading from stdin when "-" is given as the input file. Of course, the validation is multipass so there still needs to be a temporary file but I think it makes sense to hide this complexity in virt-xml-validate and not force it onto the user.
/Johannes
It looks like this could work, just a couple things...
tools/virt-xml-validate.in | 53 +++++++++++++++++++++++++++++++++------------- 1 file changed, 38 insertions(+), 15 deletions(-)
diff --git a/tools/virt-xml-validate.in b/tools/virt-xml-validate.in index a04fa06..8807f8d 100644 --- a/tools/virt-xml-validate.in +++ b/tools/virt-xml-validate.in @@ -17,6 +17,16 @@
set -e
+TMPFILE= + +cleanup() { + if [ $TMPFILE ]; then + rm -f $TMPFILE + fi +} + +trap cleanup EXIT + case $1 in -h | --h | --he | --hel | --help) cat <<EOF @@ -35,7 +45,7 @@ $0 (libvirt) @VERSION@ EOF exit ;; --) shift ;; - -*) + -?*) echo "$0: unrecognized option '$1'" >&2 exit 1 ;; esac @@ -43,18 +53,27 @@ esac XMLFILE="$1" TYPE="$2"
-if [ -z "$XMLFILE" ]; then - echo "syntax: $0 XMLFILE [TYPE]" >&2 - exit 1 -fi - -if [ ! -f "$XMLFILE" ]; then - echo "$0: document $XMLFILE does not exist" >&2 - exit 2 +if [ "$XMLFILE" = "-" ]; then + TMPFILE=`mktemp --tmpdir virt-xml.XXXX` + cat > $TMPFILE
Why don't you just set XMLFILE="$TMPFILE" ? That would get rid of lot of the code changes below and would be more readable. Other than that it looks good.
+else + if [ -z "$XMLFILE" ]; then + echo "syntax: $0 XMLFILE [TYPE]" >&2 + exit 1 + fi + + if [ ! -f "$XMLFILE" ]; then + echo "$0: document $XMLFILE does not exist" >&2 + exit 2 + fi fi
if [ -z "$TYPE" ]; then - ROOT=`xmllint --stream --debug "$XMLFILE" 2>/dev/null | grep "^0 1 " | awk '{ print $3 }'` + if [ $TMPFILE ]; then + ROOT=`cat "$TMPFILE" | xmllint --stream --debug - 2>/dev/null | grep "^0 1 " | awk '{ print $3 }'` + else + ROOT=`xmllint --stream --debug "$XMLFILE" 2>/dev/null | grep "^0 1 " | awk '{ print $3 }'` + fi case "$ROOT" in *domainsnapshot*) # Must come first, since *domain* is a substring TYPE="domainsnapshot" @@ -99,8 +118,11 @@ if [ ! -f "$SCHEMA" ]; then exit 4 fi
-xmllint --noout --relaxng "$SCHEMA" "$XMLFILE" - +if [ $TMPFILE ]; then + cat "$TMPFILE" | xmllint --noout --relaxng "$SCHEMA" - +else + xmllint --noout --relaxng "$SCHEMA" "$XMLFILE" +fi exit
: <<=cut @@ -119,9 +141,10 @@ exit
Validates a libvirt XML for compliance with the published schema. The first compulsory argument is the path to the XML file to be -validated. The optional second argument is the name of the schema -to validate against. If omitted, the schema name will be inferred -from the name of the root element in the XML document. +validated (or - to read the XML from standard input). The optional +second argument is the name of the schema to validate against. If +omitted, the schema name will be inferred from the name of the root +element in the XML document.
Valid schema names currently include
-- 1.9.1
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----- On 24 Jun, 2015, at 09:14, Martin Kletzander mkletzan@redhat.com wrote:
Why don't you just set XMLFILE="$TMPFILE" ? That would get rid of lot of the code changes below and would be more readable.
Other than that it looks good.
Good question, with a somewhat long answer. I initially did exactly what you suggest, and yes, it makes for simpler code. The only problem with it is that when xmllint finds a problem with the xml, it will output a string on the format "file name:line number: error description". If the file was provided on stdin, the file name will be something like "/tmp/virt-xml.asdf" which will not make much sense to the user. So instead I tried to be consistent: if virt-xml-validate received a filename, xmllint will receive a filename. If virt-xml-validate received data on stdin, xmllint will receive data on stdin. This way, when the xml is provided on stdin and xmllint finds a problem, the file name in the error message will just show up as "-", which is probably more in line with what the user was expecting. Anyway, it's not something I feel super-strongly about, so if you prefer to have it changed, just let me know and I'll have an updated patch for you. /Johannes
On Wed, Jun 24, 2015 at 06:17:35PM +0200, Johannes Holmberg wrote:
----- On 24 Jun, 2015, at 09:14, Martin Kletzander mkletzan@redhat.com wrote:
Why don't you just set XMLFILE="$TMPFILE" ? That would get rid of lot of the code changes below and would be more readable.
Other than that it looks good.
Good question, with a somewhat long answer. I initially did exactly what you suggest, and yes, it makes for simpler code. The only problem with it is that when xmllint finds a problem with the xml, it will output a string on the format "file name:line number: error description". If the file was provided on stdin, the file name will be something like "/tmp/virt-xml.asdf" which will not make much sense to the user. So instead I tried to be consistent: if virt-xml-validate received a filename, xmllint will receive a filename. If virt-xml-validate received data on stdin, xmllint will receive data on stdin. This way, when the xml is provided on stdin and xmllint finds a problem, the file name in the error message will just show up as "-", which is probably more in line with what the user was expecting.
Anyway, it's not something I feel super-strongly about, so if you prefer to have it changed, just let me know and I'll have an updated patch for you.
I'm on the edge here. You've got perfectly good point here. If there was at least a way of simplifying each condition somehow. Each such approach pollutes the code with 'eval' or new function that makes it even more unreadable :( Anyway, I'm going into too much unnecessary details. Thanks to your explanation I'm OK with your approach, I would suggest just one teeny tiny change, and that's using 'xmllint - < $file' instead of 'cat $file | xmllint -'. If that's ok with you, just Cc me on the v2 and I'll have a look at it. Thanks, Martin
participants (2)
-
Johannes Holmberg -
Martin Kletzander