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[PULL 05/18] docs/devel: update error handling guidance for HMP commands
From: |
Daniel P . Berrangé |
Subject: |
[PULL 05/18] docs/devel: update error handling guidance for HMP commands |
Date: |
Tue, 2 Nov 2021 17:56:47 +0000 |
Best practice is to use the 'hmp_handle_error' function, not
'monitor_printf' or 'error_report_err'. This ensures that the
message always gets an 'Error: ' prefix, distinguishing it
from normal command output.
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
docs/devel/writing-monitor-commands.rst | 19 +++++++------------
1 file changed, 7 insertions(+), 12 deletions(-)
diff --git a/docs/devel/writing-monitor-commands.rst
b/docs/devel/writing-monitor-commands.rst
index a973c48f66..a381b52024 100644
--- a/docs/devel/writing-monitor-commands.rst
+++ b/docs/devel/writing-monitor-commands.rst
@@ -293,9 +293,7 @@ Here's the implementation of the "hello-world" HMP command::
Error *err = NULL;
qmp_hello_world(!!message, message, &err);
- if (err) {
- monitor_printf(mon, "%s\n", error_get_pretty(err));
- error_free(err);
+ if (hmp_handle_error(mon, err)) {
return;
}
}
@@ -307,9 +305,10 @@ There are three important points to be noticed:
1. The "mon" and "qdict" arguments are mandatory for all HMP functions. The
former is the monitor object. The latter is how the monitor passes
arguments entered by the user to the command implementation
-2. hmp_hello_world() performs error checking. In this example we just print
- the error description to the user, but we could do more, like taking
- different actions depending on the error qmp_hello_world() returns
+2. hmp_hello_world() performs error checking. In this example we just call
+ hmp_handle_error() which prints a message to the user, but we could do
+ more, like taking different actions depending on the error
+ qmp_hello_world() returns
3. The "err" variable must be initialized to NULL before performing the
QMP call
@@ -466,9 +465,7 @@ Here's the HMP counterpart of the query-alarm-clock
command::
Error *err = NULL;
clock = qmp_query_alarm_clock(&err);
- if (err) {
- monitor_printf(mon, "Could not query alarm clock information\n");
- error_free(err);
+ if (hmp_handle_error(mon, err)) {
return;
}
@@ -607,9 +604,7 @@ has to traverse the list, it's shown below for reference::
Error *err = NULL;
method_list = qmp_query_alarm_methods(&err);
- if (err) {
- monitor_printf(mon, "Could not query alarm methods\n");
- error_free(err);
+ if (hmp_handle_error(mon, err)) {
return;
}
--
2.31.1
- [PULL 00/18] HMP-to-QMP info command patches, Daniel P . Berrangé, 2021/11/02
- [PULL 01/18] monitor: remove 'info ioapic' HMP command, Daniel P . Berrangé, 2021/11/02
- [PULL 02/18] monitor: make hmp_handle_error return a boolean, Daniel P . Berrangé, 2021/11/02
- [PULL 03/18] docs/devel: rename file for writing monitor commands, Daniel P . Berrangé, 2021/11/02
- [PULL 04/18] docs/devel: tweak headings in monitor command docs, Daniel P . Berrangé, 2021/11/02
- [PULL 05/18] docs/devel: update error handling guidance for HMP commands,
Daniel P . Berrangé <=
- [PULL 06/18] monitor: introduce HumanReadableText and HMP support, Daniel P . Berrangé, 2021/11/02
- [PULL 07/18] docs/devel: document expectations for QAPI data modelling for QMP, Daniel P . Berrangé, 2021/11/02
- [PULL 08/18] docs/devel: add example of command returning unstructured text, Daniel P . Berrangé, 2021/11/02
- [PULL 09/18] docs/devel: document expectations for HMP commands in the future, Daniel P . Berrangé, 2021/11/02
- [PULL 10/18] qapi: introduce x-query-roms QMP command, Daniel P . Berrangé, 2021/11/02
- [PULL 11/18] qapi: introduce x-query-profile QMP command, Daniel P . Berrangé, 2021/11/02
- [PULL 12/18] qapi: introduce x-query-numa QMP command, Daniel P . Berrangé, 2021/11/02
- [PULL 13/18] qapi: introduce x-query-usb QMP command, Daniel P . Berrangé, 2021/11/02
- [PULL 14/18] qapi: introduce x-query-rdma QMP command, Daniel P . Berrangé, 2021/11/02
- [PULL 15/18] qapi: introduce x-query-ramblock QMP command, Daniel P . Berrangé, 2021/11/02