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scripts: qmp-shell: add transaction support

PATCH Applied John Snow 4 participants 15 messages Apr 29, 2015 – May 8, 2015

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John Snow

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#0 lore raw

v4 cover scripts: qmp-shell: add transaction support

The qmp-shell is a little rudimentary, but it can be hacked to give us some transactional support without too much difficulty.

(1) Prep.
(2) Add support for serializing json arrays and improve the robustness of QMP parsing
(3) Add a special transaction( ... ) syntax that lets users build up transactional commands using the existing qmp shell syntax to define each action.
(4) Add a verbose flag to display generated QMP commands.

The parsing is not as robust as one would like, but this suffices without adding a proper parser.

Design considerations:

(1) Try not to disrupt the existing design of the qmp-shell. The existing API is not disturbed.
(2) Pick a "magic token" such that it could not be confused for legitimate QMP/JSON syntax. Parentheses are used for this purpose.

For convenience, this branch is available at:
https://github.com/jnsnow/qemu.git branch qmp-shell++ This version is tagged qmp-shell++-v4.

===
v++
===

- Use the AST to allow 'true', 'false' and 'null' within QMP expressions
- Fix a bunch of stupid junk I broke in v2, apparently.

===
v3:
===

- Folding in hotfix from list (import ast)

===
v2:
===

- Squash patches 2 & 3:
- Remove wholesale replacement of single quotes, in favor of try blocks that attempt to parse as pure JSON, then as Python.
- Factored out the value parser block to accomplish the above.
- Allow both true/True and false/False for values.
- Fix typo in patch 3 cover letter. (was patch 4.)

John Snow (4):
scripts: qmp-shell: refactor helpers
scripts: qmp-shell: Expand support for QMP expressions
scripts: qmp-shell: add transaction subshell
scripts: qmp-shell: Add verbose flag

 scripts/qmp/qmp-shell | 147 +++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 116 insertions(+), 31 deletions(-)
Signature · 1 line
2.1.0
author
#1 lore raw

PATCH v4 1/4 scripts: qmp-shell: refactor helpers

Refactor the qmp-shell command line processing function into two components. This will be used to allow sub-expressions, which will assist us in adding transactional support to qmp-shell.

---
 scripts/qmp/qmp-shell | 24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)
scripts/qmp/qmp-shell +13 -11
index e0e848b..a9632ec 100755
@@ -88,16 +88,8 @@ class QMPShell(qmp.QEMUMonitorProtocol):
         # clearing everything as it doesn't seem to matter
         readline.set_completer_delims('')
 
-    def __build_cmd(self, cmdline):
-        """
-        Build a QMP input object from a user provided command-line in the
-        following format:
-
-            < command-name > [ arg-name1=arg1 ] ... [ arg-nameN=argN ]
-        """
-        cmdargs = cmdline.split()
-        qmpcmd = { 'execute': cmdargs[0], 'arguments': {} }
-        for arg in cmdargs[1:]:
+    def __cli_expr(self, tokens, parent):
+        for arg in tokens:
             opt = arg.split('=')
             try:
                 if(len(opt) > 2):
@@ -113,7 +105,6 @@ class QMPShell(qmp.QEMUMonitorProtocol):
                 else:
                     value = opt[1]
             optpath = opt[0].split('.')
-            parent = qmpcmd['arguments']
             curpath = []
             for p in optpath[:-1]:
                 curpath.append(p)
@@ -128,6 +119,17 @@ class QMPShell(qmp.QEMUMonitorProtocol):
                 else:
                     raise QMPShellError('Cannot set "%s" multiple times' % opt[0])
             parent[optpath[-1]] = value
+
+    def __build_cmd(self, cmdline):
+        """
+        Build a QMP input object from a user provided command-line in the
+        following format:
+
+            < command-name > [ arg-name1=arg1 ] ... [ arg-nameN=argN ]
+        """
+        cmdargs = cmdline.split()
+        qmpcmd = { 'execute': cmdargs[0], 'arguments': {} }
+        self.__cli_expr(cmdargs[1:], qmpcmd['arguments'])
         return qmpcmd
 
     def _execute_cmd(self, cmdline):
Signature · 1 line
2.1.0
author
#2 lore raw

PATCH v4 2/4 scripts: qmp-shell: Expand support for QMP expressions

In reply to John Snow

This includes support for [] expressions, single-quotes in QMP expressions (which is not strictly a part of JSON), and the ability to use "True", "False" and "None" literals instead of JSON's equivalent true, false, and null literals.

qmp-shell currently allows you to describe values as JSON expressions:
key={"key":{"key2":"val"}}

But it does not currently support arrays, which are needed for serializing and deserializing transactions:
key=[{"type":"drive-backup","data":{...}}]

qmp-shell also only currently accepts doubly quoted strings as-per JSON spec, but QMP allows single quotes.

Lastly, python allows you to utilize "True" or "False" as boolean literals, but JSON expects "true" or "false". Expand qmp-shell to allow the user to type either, converting to the correct type.

As a consequence of the above, the key=val parsing is also improved to give better error messages if a key=val token is not provided.

CAVEAT: The parser is still extremely rudimentary and does not expect to find spaces in {} nor [] expressions. This patch does not improve this functionality.

---
 scripts/qmp/qmp-shell | 63 ++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 47 insertions(+), 16 deletions(-)
scripts/qmp/qmp-shell +47 -16
index a9632ec..7f2c554 100755
@@ -32,6 +32,7 @@
 
 import qmp
 import json
+import ast
 import readline
 import sys
 import pprint
@@ -51,6 +52,19 @@ class QMPShellError(Exception):
 class QMPShellBadPort(QMPShellError):
     pass
 
+class FuzzyJSON(ast.NodeTransformer):
+    '''This extension of ast.NodeTransformer filters literal "true/false/null"
+    values in an AST and replaces them by proper "True/False/None" values that
+    Python can properly evaluate.'''
+    def visit_Name(self, node):
+        if node.id == 'true':
+            node.id = 'True'
+        if node.id == 'false':
+            node.id = 'False'
+        if node.id == 'null':
+            node.id = 'None'
+        return node
+
 # TODO: QMPShell's interface is a bit ugly (eg. _fill_completion() and
 #       _execute_cmd()). Let's design a better one.
 class QMPShell(qmp.QEMUMonitorProtocol):
@@ -88,23 +102,40 @@ class QMPShell(qmp.QEMUMonitorProtocol):
         # clearing everything as it doesn't seem to matter
         readline.set_completer_delims('')
 
+    def __parse_value(self, val):
+        try:
+            return int(val)
+        except ValueError:
+            pass
+
+        if val.lower() == 'true':
+            return True
+        if val.lower() == 'false':
+            return False
+        if val.startswith(('{', '[')):
+            # Try first as pure JSON:
+            try:
+                return json.loads(val)
+            except ValueError:
+                pass
+            # Try once again as FuzzyJSON:
+            try:
+                st = ast.parse(val, mode='eval')
+                return ast.literal_eval(FuzzyJSON().visit(st))
+            except SyntaxError:
+                pass
+            except ValueError:
+                pass
+        return val
+
     def __cli_expr(self, tokens, parent):
         for arg in tokens:
-            opt = arg.split('=')
-            try:
-                if(len(opt) > 2):
-                    opt[1] = '='.join(opt[1:])
-                value = int(opt[1])
-            except ValueError:
-                if opt[1] == 'true':
-                    value = True
-                elif opt[1] == 'false':
-                    value = False
-                elif opt[1].startswith('{'):
-                    value = json.loads(opt[1])
-                else:
-                    value = opt[1]
-            optpath = opt[0].split('.')
+            (key, _, val) = arg.partition('=')
+            if not val:
+                raise QMPShellError("Expected a key=value pair, got '%s'" % arg)
+
+            value = self.__parse_value(val)
+            optpath = key.split('.')
             curpath = []
             for p in optpath[:-1]:
                 curpath.append(p)
@@ -117,7 +148,7 @@ class QMPShell(qmp.QEMUMonitorProtocol):
                 if type(parent[optpath[-1]]) is dict:
                     raise QMPShellError('Cannot use "%s" as both leaf and non-leaf key' % '.'.join(curpath))
                 else:
-                    raise QMPShellError('Cannot set "%s" multiple times' % opt[0])
+                    raise QMPShellError('Cannot set "%s" multiple times' % key)
             parent[optpath[-1]] = value
 
     def __build_cmd(self, cmdline):
Signature · 1 line
2.1.0
Reviewed-by on v4 2/4
#3 lore raw

Re: [Qemu-devel] [PATCH v4 2/4] scripts: qmp-shell: Expand support for QMP expressions

Quoted 37 lines · John Snow

This includes support for [] expressions, single-quotes in QMP expressions (which is not strictly a part of JSON), and the ability to use "True", "False" and "None" literals instead of JSON's equivalent true, false, and null literals.

qmp-shell currently allows you to describe values as JSON expressions:
key={"key":{"key2":"val"}}

But it does not currently support arrays, which are needed for serializing and deserializing transactions:
key=[{"type":"drive-backup","data":{...}}]

qmp-shell also only currently accepts doubly quoted strings as-per JSON spec, but QMP allows single quotes.

Lastly, python allows you to utilize "True" or "False" as boolean literals, but JSON expects "true" or "false". Expand qmp-shell to allow the user to type either, converting to the correct type.

As a consequence of the above, the key=val parsing is also improved to give better error messages if a key=val token is not provided.

CAVEAT: The parser is still extremely rudimentary and does not expect to find spaces in {} nor [] expressions. This patch does not improve this functionality.

---
 scripts/qmp/qmp-shell | 63 ++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 47 insertions(+), 16 deletions(-)
scripts/qmp/qmp-shell +2 -0
+class FuzzyJSON(ast.NodeTransformer):
+    '''This extension of ast.NodeTransformer filters literal "true/false/null"

scripts/qmp/qmp-shell class QMPShellError(Exception): · line 66

Quoted 10 lines
scripts/qmp/qmp-shell +10 -0
+    values in an AST and replaces them by proper "True/False/None" values that
+    Python can properly evaluate.'''
+    def visit_Name(self, node):
+        if node.id == 'true':
+            node.id = 'True'
+        if node.id == 'false':
+            node.id = 'False'
+        if node.id == 'null':
+            node.id = 'None'
+        return node

Cute!

Signature · 2 lines
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org
author
#4 lore raw

Re: [Qemu-devel] [PATCH v4 2/4] scripts: qmp-shell: Expand support for QMP expressions

Quoted 49 lines · Eric Blake
Quoted 37 lines · John Snow

This includes support for [] expressions, single-quotes in QMP expressions (which is not strictly a part of JSON), and the ability to use "True", "False" and "None" literals instead of JSON's equivalent true, false, and null literals.

qmp-shell currently allows you to describe values as JSON expressions:
key={"key":{"key2":"val"}}

But it does not currently support arrays, which are needed for serializing and deserializing transactions:
key=[{"type":"drive-backup","data":{...}}]

qmp-shell also only currently accepts doubly quoted strings as-per JSON spec, but QMP allows single quotes.

Lastly, python allows you to utilize "True" or "False" as boolean literals, but JSON expects "true" or "false". Expand qmp-shell to allow the user to type either, converting to the correct type.

As a consequence of the above, the key=val parsing is also improved to give better error messages if a key=val token is not provided.

CAVEAT: The parser is still extremely rudimentary and does not expect to find spaces in {} nor [] expressions. This patch does not improve this functionality.

---
  scripts/qmp/qmp-shell | 63 ++++++++++++++++++++++++++++++++++++++-------------
  1 file changed, 47 insertions(+), 16 deletions(-)
scripts/qmp/qmp-shell +2 -0
+class FuzzyJSON(ast.NodeTransformer):
+    '''This extension of ast.NodeTransformer filters literal "true/false/null"

scripts/qmp/qmp-shell class QMPShellError(Exception): · line 66

Quoted 10 lines
scripts/qmp/qmp-shell +10 -0
+    values in an AST and replaces them by proper "True/False/None" values that
+    Python can properly evaluate.'''
+    def visit_Name(self, node):
+        if node.id == 'true':
+            node.id = 'True'
+        if node.id == 'false':
+            node.id = 'False'
+        if node.id == 'null':
+            node.id = 'None'
+        return node
Quoted 2 lines

Cute!

;)

Quoted 2 lines

So the only remaining crime I am aware of is that when specifying key=val pairs without hoping for a favorable QMP deserialization is that we still accept e.g. "TrUe" and "FaLSe" and so on.

Patch 4 tries to make amends by explicitly converting objects back to strict JSON and printing that out for the user (if they supplied -v) so we can observe what conversions qmp-shell made for us to make things nice.

And I think I'm done playing with this for now. If I go any further, there's bound to be flex and bison files in the tree!

--js

author
#5 lore raw

PATCH v4 3/4 scripts: qmp-shell: add transaction subshell

In reply to John Snow

Add a special processing mode to craft transactions.

By entering "transaction(" the shell will enter a special mode where each subsequent command will be saved as a transaction instead of executed as an individual command.

The transaction can be submitted by entering ")" on a line by itself.

Examples:

Separate lines:

(QEMU) transaction(
TRANS> block-dirty-bitmap-add node=drive0 name=bitmap1 TRANS> block-dirty-bitmap-clear node=drive0 name=bitmap0 TRANS> )

With a transaction action included on the first line:

(QEMU) transaction( block-dirty-bitmap-add node=drive0 name=bitmap2 TRANS> block-dirty-bitmap-add node=drive0 name=bitmap3 TRANS> )

As a one-liner, with just one transaction action:

(QEMU) transaction( block-dirty-bitmap-add node=drive0 name=bitmap0 )

As a side-effect of this patch, blank lines are now parsed as no-ops, regardless of which shell mode you are in.

---
 scripts/qmp/qmp-shell | 42 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)
scripts/qmp/qmp-shell +41 -1
index 7f2c554..1df2ca7 100755
@@ -73,6 +73,8 @@ class QMPShell(qmp.QEMUMonitorProtocol):
         self._greeting = None
         self._completer = None
         self._pp = pp
+        self._transmode = False
+        self._actions = list()
 
     def __get_address(self, arg):
         """
@@ -159,6 +161,36 @@ class QMPShell(qmp.QEMUMonitorProtocol):
             < command-name > [ arg-name1=arg1 ] ... [ arg-nameN=argN ]
         """
         cmdargs = cmdline.split()
+
+        # Transactional CLI entry/exit:
+        if cmdargs[0] == 'transaction(':
+            self._transmode = True
+            cmdargs.pop(0)
+        elif cmdargs[0] == ')' and self._transmode:
+            self._transmode = False
+            if len(cmdargs) > 1:
+                raise QMPShellError("Unexpected input after close of Transaction sub-shell")
+            qmpcmd = { 'execute': 'transaction',
+                       'arguments': { 'actions': self._actions } }
+            self._actions = list()
+            return qmpcmd
+
+        # Nothing to process?
+        if not cmdargs:
+            return None
+
+        # Parse and then cache this Transactional Action
+        if self._transmode:
+            finalize = False
+            action = { 'type': cmdargs[0], 'data': {} }
+            if cmdargs[-1] == ')':
+                cmdargs.pop(-1)
+                finalize = True
+            self.__cli_expr(cmdargs[1:], action['data'])
+            self._actions.append(action)
+            return self.__build_cmd(')') if finalize else None
+
+        # Standard command: parse and return it to be executed.
         qmpcmd = { 'execute': cmdargs[0], 'arguments': {} }
         self.__cli_expr(cmdargs[1:], qmpcmd['arguments'])
         return qmpcmd
@@ -171,6 +203,9 @@ class QMPShell(qmp.QEMUMonitorProtocol):
             print 'command format: <command-name> ',
             print '[arg-name1=arg1] ... [arg-nameN=argN]'
             return True
+        # For transaction mode, we may have just cached the action:
+        if qmpcmd is None:
+            return True
         resp = self.cmd_obj(qmpcmd)
         if resp is None:
             print 'Disconnected'
@@ -191,6 +226,11 @@ class QMPShell(qmp.QEMUMonitorProtocol):
         version = self._greeting['QMP']['version']['qemu']
         print 'Connected to QEMU %d.%d.%d\n' % (version['major'],version['minor'],version['micro'])
 
+    def get_prompt(self):
+        if self._transmode:
+            return "TRANS> "
+        return "(QEMU) "
+
     def read_exec_command(self, prompt):
         """
         Read and execute a command.
@@ -330,7 +370,7 @@ def main():
         die('Could not connect to %s' % addr)
 
     qemu.show_banner()
-    while qemu.read_exec_command('(QEMU) '):
+    while qemu.read_exec_command(qemu.get_prompt()):
         pass
     qemu.close()
 
Signature · 1 line
2.1.0
Reviewed-by on v4 3/4
#6 lore raw

Re: [Qemu-devel] [PATCH v4 3/4] scripts: qmp-shell: add transaction subshell

Quoted 9 lines · John Snow

Add a special processing mode to craft transactions.

By entering "transaction(" the shell will enter a special mode where each subsequent command will be saved as a transaction instead of executed as an individual command.

The transaction can be submitted by entering ")" on a line by itself.

Quoted 8 lines

As a side-effect of this patch, blank lines are now parsed as no-ops, regardless of which shell mode you are in.

---
 scripts/qmp/qmp-shell | 42 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)
Signature · 2 lines
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org
author
#7 lore raw

PATCH v4 4/4 scripts: qmp-shell: Add verbose flag

In reply to John Snow

Add a verbose flag that shows the QMP command that was constructed, to allow for later copy/pasting, reference, debugging, etc.

The QMP is converted from a Python literal to JSON first, to ensure that it is viable input to the actual QMP parser.

As a side-effect, this JSON output will helpfully show all the necessary conversions that were performed on the input, illustrating that "True" was transformed back into "true", literal values are now escaped with "" instead of '', and so on.

---
 scripts/qmp/qmp-shell | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)
scripts/qmp/qmp-shell +18 -6
index 1df2ca7..65280d2 100755
@@ -195,6 +195,13 @@ class QMPShell(qmp.QEMUMonitorProtocol):
         self.__cli_expr(cmdargs[1:], qmpcmd['arguments'])
         return qmpcmd
 
+    def _print(self, qmp):
+        jsobj = json.dumps(qmp)
+        if self._pp is not None:
+            self._pp.pprint(jsobj)
+        else:
+            print str(jsobj)
+
     def _execute_cmd(self, cmdline):
         try:
             qmpcmd = self.__build_cmd(cmdline)
@@ -206,15 +213,13 @@ class QMPShell(qmp.QEMUMonitorProtocol):
         # For transaction mode, we may have just cached the action:
         if qmpcmd is None:
             return True
+        if self._verbose:
+            self._print(qmpcmd)
         resp = self.cmd_obj(qmpcmd)
         if resp is None:
             print 'Disconnected'
             return False
-
-        if self._pp is not None:
-            self._pp.pprint(resp)
-        else:
-            print resp
+        self._print(resp)
         return True
 
     def connect(self):
@@ -250,6 +255,9 @@ class QMPShell(qmp.QEMUMonitorProtocol):
         else:
             return self._execute_cmd(cmdline)
 
+    def set_verbosity(self, verbose):
+        self._verbose = verbose
+
 class HMPShell(QMPShell):
     def __init__(self, address):
         QMPShell.__init__(self, address)
@@ -327,7 +335,7 @@ def die(msg):
 def fail_cmdline(option=None):
     if option:
         sys.stderr.write('ERROR: bad command-line option \'%s\'\n' % option)
-    sys.stderr.write('qemu-shell [ -p ] [ -H ] < UNIX socket path> | < TCP address:port >\n')
+    sys.stderr.write('qemu-shell [ -v ] [ -p ] [ -H ] < UNIX socket path> | < TCP address:port >\n')
     sys.exit(1)
 
 def main():
@@ -335,6 +343,7 @@ def main():
     qemu = None
     hmp = False
     pp = None
+    verbose = False
 
     try:
         for arg in sys.argv[1:]:
@@ -346,6 +355,8 @@ def main():
                 if pp is not None:
                     fail_cmdline(arg)
                 pp = pprint.PrettyPrinter(indent=4)
+            elif arg == "-v":
+                verbose = True
             else:
                 if qemu is not None:
                     fail_cmdline(arg)
@@ -370,6 +381,7 @@ def main():
         die('Could not connect to %s' % addr)
 
     qemu.show_banner()
+    qemu.set_verbosity(verbose)
     while qemu.read_exec_command(qemu.get_prompt()):
         pass
     qemu.close()
Signature · 1 line
2.1.0
Reviewed-by on v4 4/4
#8 lore raw

Re: [Qemu-devel] [PATCH v4 4/4] scripts: qmp-shell: Add verbose flag

Quoted 12 lines · John Snow

Add a verbose flag that shows the QMP command that was constructed, to allow for later copy/pasting, reference, debugging, etc.

The QMP is converted from a Python literal to JSON first, to ensure that it is viable input to the actual QMP parser.

As a side-effect, this JSON output will helpfully show all the necessary conversions that were performed on the input, illustrating that "True" was transformed back into "true", literal values are now escaped with "" instead of '', and so on.

Quoted 5 lines
---
 scripts/qmp/qmp-shell | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)
Signature · 2 lines
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org
Tested-by on the v4 series
#9 lore raw
In reply to John Snow
Quoted 49 lines · John Snow

The qmp-shell is a little rudimentary, but it can be hacked to give us some transactional support without too much difficulty.

(1) Prep.
(2) Add support for serializing json arrays and improve the robustness of QMP parsing
(3) Add a special transaction( ... ) syntax that lets users build up transactional commands using the existing qmp shell syntax to define each action.
(4) Add a verbose flag to display generated QMP commands.

The parsing is not as robust as one would like, but this suffices without adding a proper parser.

Design considerations:

(1) Try not to disrupt the existing design of the qmp-shell. The existing API is not disturbed.
(2) Pick a "magic token" such that it could not be confused for legitimate QMP/JSON syntax. Parentheses are used for this purpose.

For convenience, this branch is available at:
https://github.com/jnsnow/qemu.git branch qmp-shell++ This version is tagged qmp-shell++-v4.

===
v++
===

- Use the AST to allow 'true', 'false' and 'null' within QMP expressions
- Fix a bunch of stupid junk I broke in v2, apparently.

===
v3:
===

- Folding in hotfix from list (import ast)

===
v2:
===

- Squash patches 2 & 3:
- Remove wholesale replacement of single quotes, in favor of try blocks that attempt to parse as pure JSON, then as Python.
- Factored out the value parser block to accomplish the above.
- Allow both true/True and false/False for values.
- Fix typo in patch 3 cover letter. (was patch 4.)

Quoted 8 lines

John Snow (4):
scripts: qmp-shell: refactor helpers
scripts: qmp-shell: Expand support for QMP expressions
scripts: qmp-shell: add transaction subshell
scripts: qmp-shell: Add verbose flag

 scripts/qmp/qmp-shell | 147 +++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 116 insertions(+), 31 deletions(-)

Quick test, works as advertized. This time, I ran this series on top of your incremental backup branch:

A positive test (sorry for the un-wrapped long lines). I already had the target image pre-created:

$ ./qmp-shell -v ./qmp-sock
Welcome to the QMP low-level shell!
Connected to QEMU 2.2.94
(QEMU)
(QEMU) transaction(
TRANS> blockdev-snapshot-internal-sync device=drive-ide0-0-0 name=snapshot5
TRANS> block-dirty-bitmap-add node=drive-ide0-0-0 name=bitmap1
TRANS> block-dirty-bitmap-clear node=drive-ide0-0-0 name=bitmap0                                                                                                                           
TRANS> drive-backup device=drive-ide0-0-0 bitmap=bitmap1 sync=dirty-bitmap target=./incremental.0.img mode=existing format=qcow2
TRANS> )
{"execute": "transaction", "arguments": {"actions": [{"data": {"device": "drive-ide0-0-0", "name": "snapshot5"}, "type": "blockdev-snapshot-internal-sync"}, {"data": {"node": "drive-ide0-0-0", "name": "bitmap1"}, "type": "block-dirty-bitmap-add"}, {"data": {"node": "drive-ide0-0-0", "name": "bitmap0"}, "type": "block-dirty-bitmap-clear"}, {"data": {"target": "./incremental.0.img", "format": "qcow2", "sync": "dirty-bitmap", "bitmap": "bitmap1", "mode": "existing", "device": "drive-ide0-0-0"}, "type": "drive-backup"}]}}
{"return": {}}
(QEMU)

And a quick negative test: don't pre-create the target image when running the drive-backup command, appropriate error is thrown.

So, FWIW:

Signature · 1 line
/kashyap
author
#10 lore raw
In reply to John Snow

Ping
(I should've CC'd Luiz to begin with ...)

Eric's given this series the once over and Kashyap has tested it, so it should in theory be good to go.

Quoted 58 lines · John Snow

The qmp-shell is a little rudimentary, but it can be hacked to give us some transactional support without too much difficulty.

(1) Prep.
(2) Add support for serializing json arrays and
improve the robustness of QMP parsing
(3) Add a special transaction( ... ) syntax that lets users build up transactional commands using the existing qmp shell syntax to define each action.
(4) Add a verbose flag to display generated QMP commands.

The parsing is not as robust as one would like, but this suffices without adding a proper parser.

Design considerations:

(1) Try not to disrupt the existing design of the qmp-shell. The existing API is not disturbed.
(2) Pick a "magic token" such that it could not be confused for legitimate QMP/JSON syntax. Parentheses are used for this purpose.

For convenience, this branch is available at:
https://github.com/jnsnow/qemu.git branch qmp-shell++ This version is tagged qmp-shell++-v4.

===
v++
===

- Use the AST to allow 'true', 'false' and 'null' within QMP expressions
- Fix a bunch of stupid junk I broke in v2, apparently.

===
v3:
===

- Folding in hotfix from list (import ast)

===
v2:
===

- Squash patches 2 & 3:
- Remove wholesale replacement of single quotes, in favor of try blocks that attempt to parse as pure JSON, then as Python.
- Factored out the value parser block to accomplish the above.
- Allow both true/True and false/False for values.
- Fix typo in patch 3 cover letter. (was patch 4.)

John Snow (4):
scripts: qmp-shell: refactor helpers
scripts: qmp-shell: Expand support for QMP expressions
scripts: qmp-shell: add transaction subshell
scripts: qmp-shell: Add verbose flag

  scripts/qmp/qmp-shell | 147 +++++++++++++++++++++++++++++++++++++++-----------
  1 file changed, 116 insertions(+), 31 deletions(-)
#11 lore raw
Quoted 5 lines · On Mon, 04 May 2015 15:24:02 -0400 John Snow <[email protected]> wrote:

Ping
(I should've CC'd Luiz to begin with ...)

Eric's given this series the once over and Kashyap has tested it, so it should in theory be good to go.

I lost track of it. Is v4 a new posting?

Quoted 61 lines · John Snow
Quoted 58 lines

The qmp-shell is a little rudimentary, but it can be hacked to give us some transactional support without too much difficulty.

(1) Prep.
(2) Add support for serializing json arrays and
improve the robustness of QMP parsing
(3) Add a special transaction( ... ) syntax that lets users build up transactional commands using the existing qmp shell syntax to define each action.
(4) Add a verbose flag to display generated QMP commands.

The parsing is not as robust as one would like, but this suffices without adding a proper parser.

Design considerations:

(1) Try not to disrupt the existing design of the qmp-shell. The existing API is not disturbed.
(2) Pick a "magic token" such that it could not be confused for legitimate QMP/JSON syntax. Parentheses are used for this purpose.

For convenience, this branch is available at:
https://github.com/jnsnow/qemu.git branch qmp-shell++ This version is tagged qmp-shell++-v4.

===
v++
===

- Use the AST to allow 'true', 'false' and 'null' within QMP expressions
- Fix a bunch of stupid junk I broke in v2, apparently.

===
v3:
===

- Folding in hotfix from list (import ast)

===
v2:
===

- Squash patches 2 & 3:
- Remove wholesale replacement of single quotes, in favor of try blocks that attempt to parse as pure JSON, then as Python.
- Factored out the value parser block to accomplish the above.
- Allow both true/True and false/False for values.
- Fix typo in patch 3 cover letter. (was patch 4.)

John Snow (4):
scripts: qmp-shell: refactor helpers
scripts: qmp-shell: Expand support for QMP expressions
scripts: qmp-shell: add transaction subshell
scripts: qmp-shell: Add verbose flag

  scripts/qmp/qmp-shell | 147 +++++++++++++++++++++++++++++++++++++++-----------
  1 file changed, 116 insertions(+), 31 deletions(-)
author
#12 lore raw
Quoted 1 line · Luiz Capitulino

I lost track of it. Is v4 a new posting?

Yup. Latest with fixes. Eric re-reviewed it all and Kashyap (and I) tested it.

--js

#13 lore raw
Quoted 7 lines · On Tue, 05 May 2015 11:34:02 -0400 John Snow <[email protected]> wrote:
Quoted 1 line · Luiz Capitulino

I lost track of it. Is v4 a new posting?

Yup. Latest with fixes. Eric re-reviewed it all and Kashyap (and I) tested it.

OK, I'm queuing it for my next pass over my qmp-patches mailbox.

#14 lore raw
In reply to John Snow
Quoted 16 lines · On Wed, 29 Apr 2015 15:14:00 -0400 John Snow <[email protected]> wrote:

The qmp-shell is a little rudimentary, but it can be hacked to give us some transactional support without too much difficulty.

(1) Prep.
(2) Add support for serializing json arrays and improve the robustness of QMP parsing
(3) Add a special transaction( ... ) syntax that lets users build up transactional commands using the existing qmp shell syntax to define each action.
(4) Add a verbose flag to display generated QMP commands.

The parsing is not as robust as one would like, but this suffices without adding a proper parser.

Design considerations:

Quoted 8 lines

(1) Try not to disrupt the existing design of the qmp-shell. The existing API is not disturbed.
(2) Pick a "magic token" such that it could not be confused for legitimate QMP/JSON syntax. Parentheses are used for this purpose.

For convenience, this branch is available at:
https://github.com/jnsnow/qemu.git branch qmp-shell++ This version is tagged qmp-shell++-v4.

Applied to the qmp branch, thanks.

Quoted 34 lines

===
v++
===

- Use the AST to allow 'true', 'false' and 'null' within QMP expressions
- Fix a bunch of stupid junk I broke in v2, apparently.

===
v3:
===

- Folding in hotfix from list (import ast)

===
v2:
===

- Squash patches 2 & 3:
- Remove wholesale replacement of single quotes, in favor of try blocks that attempt to parse as pure JSON, then as Python.
- Factored out the value parser block to accomplish the above.
- Allow both true/True and false/False for values.
- Fix typo in patch 3 cover letter. (was patch 4.)

John Snow (4):
scripts: qmp-shell: refactor helpers
scripts: qmp-shell: Expand support for QMP expressions
scripts: qmp-shell: add transaction subshell
scripts: qmp-shell: Add verbose flag

 scripts/qmp/qmp-shell | 147 +++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 116 insertions(+), 31 deletions(-)