This text provides several use-case of the yanglint(1) interactive
mode. For basic information about the yanglint(1) usage, please see
the man page.
The examples are supposed to be went through one by one. Some of the examples suppose the specific schemas loaded in some of the previous example is still loaded. If an addition work is need, the preparation part in the example provides information what to do.
To show all available command of the yanglint(1), use the help command:
> help
Available commands:
help Display commands description
add Add a new model
print Print model
data Load, validate and optionally print instance data
xpath Get data nodes satisfying an XPath expression
list List all the loaded models
feature Print/enable/disable all/specific features of models
searchpath Set the search path for models
clear Clear the context - remove all the loaded models
verb Change verbosity
quit Quit the program
? Display commands description
exit Quit the program
To show the information about the specific command, use the help command in
combination with the command name you are interested in:
> help searchpath
searchpath <model-dir-path>
The input files referred in this document are available together with this document.
Let's have two data models module1.yang and module1b.yang. They differ in the module name but their namespaces are the same.
Preparation:
> clear
> add module1.yang
> list
Output:
List of the loaded models (mod-set-id 5):
ietf-inet-types@2013-07-15
ietf-yang-types@2013-07-15
ietf-yang-library@2015-07-03
module1
Command and its output:
> add module1b.yang
libyang[0]: Two different modules ("module1" and "module1b") have the same namespace "urn:yanglint:module".
libyang[0]: Module "module1b" parsing failed.
YANG/YIN syntax
module2.yin contains a syntax error.
There is a bad syntax of the type statement in YIN file.
<type value="string"/>
instead of
<type name="string"/>
Preparation:
> clear
Command and its output:
> add module2.yin
libyang[0]: Missing argument "name" to keyword "type".
libyang[0]: Module "module1" parsing failed.
Similarly, there is a typo in module2.yang.
XPath errors
libyang and yanglint(1) is able to detect also errors in XPath expressions.
In module3.yang the must expression refers to the node which does not exists.
Preparation:
> clear
Command and its output:
> add module3.yang
libyang[0]: Schema node "a" not found (../c/a).
libyang[0]: Path is related to the previous error message. (path: /module3:m)
libyang[0]: Module "module3" parsing failed.
Note that libyang does not provide line numbers of the error. Instead it tries to
print the path to the related node. in some cases (as this one) it is not able
to print the path immediately so the path (to the node m which refers node which
does not exist) is printed in the second message.
Preparation:
> clear
> add ietf-netconf-acm.yang
Unknown data
By default, yanglint ignores unknown data and no error is printed (you can
compare real content of the datastore.xml file and what yanglint prints
in the following command if you add -f xml option).
Command and its output:
> data -t config datastore.xml
We use option -t to specify type of the data in datastore.xml. By the
config value we declare that the input file contains all the configuration
data (with at least all the mandatory nodes as required by the loaded schemas),
but without the status data. More examples of different data types will follow.
To handle unknown data as error, use strict mode (-s option).
Command and its output:
> data -t config -s datastore.xml
libyang[0]: Unknown element "interfaces". (path: /)
Failed to parse data.
Note that in case of working with complete datastore including the status data
(no -t option is specified), yanglint(1) has to add status data from its
internal ietf-yang-library module. Using the -s option in this case forces
validation in time of parsing the input file so it is expected to include also
the mandatory status data from the ietf-yang-library module.
RPC and RPC-reply
It is possible to validate RPCs and their replies as well.
Peparation:
> clear
> add module4.yang
Command and its output:
> data -t rpc rpc.xml
Reply to this RPC can be validated too, but it must be specified, to which RPC it is a reply to, because it is not included in the reply itself.
Command and its output:
> data -t rpcreply rpc-reply.xml rpc.xml
action and action-reply
Actions are validated the same way as RPCs except you need to be careful about the input file structure.
Preparation
> clear
> add module4.yang
Command and its output:
> data -t rpc action.xml
Command and its output:
> data -t rpc action-reply.xml action.xml
notification
Both top-level and nested notification can be validated.
Preparation
> clear
> add module4.yang
Command and its output:
> data -t notif notification.xml
Command and its output:
> data -t notif nested-notification.xml
Multiple top-level elements in a single document
As a feature and in conflict with the XML definition, yanglint(1) (and libyang)
is able to read XML files with multiple top-level elements. Such documents
are not well-formed according to the XML spec, but it fits to how the YANG
interconnects data trees (defined as top-level elements of a single schema
or by multiple schemas).
Preparation:
> clear
> add ietf-netconf-acm.yang
> add ietf-interfaces.yang
> add ietf-ip.yang
> add iana-if-type.yang
Command and its output:
> data -t config -s datastore.xml
Different data content types
Since NETCONF requires the data described by YANG to be used in different
situations (e.g. as , result of the with status data
included or as a result of the without the status data and
possibly filtered, so without specified subtrees), it must be possible to
specify which kind of data is going to be parsed. In yanglint(1), this is done
via -t option. The list of supported modes can be displayed by the -h
option given to the data command. In general, the auto value lets the
yanglint(1) to recognize the data type automatically by the additional top-level
elements added to the parsed data. This is the same way as pyang(1) uses. Note,
that the automatic data type recognition is available only for the XML input.
Malformed XML data
Command and its output:
> data -t edit config-missing-key.xml
libyang[0]: Invalid (mixed names) opening (nam) and closing (name) element tags. (path: /nacm/groups/group/nam)
Failed to parse data.
State information in edit-config XML
Command and its output:
> data -t edit config-unknown-element.xml
libyang[0]: Unknown element "denied-operations". (path: /ietf-netconf-acm:nacm/denied-operations)
Failed to parse data.
Missing required element in NETCONF data
Command and its output:
> data data-missing-key.xml
libyang[0]: Missing required element "name" in "rule". (path: /ietf-netconf-acm:nacm/rule-list[name='almighty']/rule)
Failed to parse data.
Malformed XML
Command and its output:
> data data-malformed-xml.xml
libyang[0]: Invalid (mixed names) opening (nam) and closing (rule) element tags. (path: /nacm/rule-list/rule/nam)
Failed to parse data.
Command and its output:
> data data-malformed-xml2.xml
libyang[0]: Invalid (mixed names) opening (module-name) and closing (name) element tags. (path: /nacm/rule-list/rule/name/module-name)
Failed to parse data.
Bad value
Command and its output:
> data data-out-of-range-value.xml
libyang[0]: Invalid value "-1" in "denied-operations" element. (path: /ietf-netconf-acm:nacm/denied-operations)
Failed to parse data.
Preparation:
> clear
> add ietf-netconf-acm-when.yang
When condition is not satisfied since denied-operation = 0
Command and its output:
> data data-acm.xml
The command succeeds. It is because yanglint(1) (via libyang) performs
autodeletion - the not satisfied when condition in denied-data-writes
causes its automatic (silent) deletion.
Preparation:
> clear
> add ietf-netconf-acm.yang
Print a pyang-style tree
Command and its output:
> print ietf-netconf-acm
module: ietf-netconf-acm
+--rw nacm
+--rw enable-nacm? boolean <true>
+--rw read-default? action-type <permit>
+--rw write-default? action-type <deny>
+--rw exec-default? action-type <permit>
+--rw enable-external-groups? boolean <true>
+--ro denied-operations ietf-yang-types:zero-based-counter32
+--ro denied-data-writes ietf-yang-types:zero-based-counter32
+--ro denied-notifications ietf-yang-types:zero-based-counter32
+--rw groups
| +--rw group* [name]
| +--rw name group-name-type
| +--rw user-name* user-name-type
+--rw rule-list* [name]
+--rw name string
+--rw group* union
+--rw rule* [name]
+--rw name string
+--rw module-name? union <*>
+--rw (rule-type)?
| +--:(protocol-operation)
| | +--rw rpc-name? union
| +--:(notification)
| | +--rw notification-name? union
| +--:(data-node)
| +--rw path node-instance-identifier
+--rw access-operations? union <*>
+--rw action action-type
+--rw comment? string
>
Obtain information about model
Command and its output:
> print -f info ietf-netconf-acm
Module: ietf-netconf-acm
Namespace: urn:ietf:params:xml:ns:yang:ietf-netconf-acm
Prefix: nacm
Desc: NETCONF Access Control Model.
Copyright (c) 2012 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD
License set forth in Section 4.c of the IETF Trust's
Legal Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC 6536; see
the RFC itself for full legal notices.
Reference:
Org: IETF NETCONF (Network Configuration) Working Group
Contact: WG Web: <http://tools.ietf.org/wg/netconf/>
WG List: <mailto:[email protected]>
WG Chair: Mehmet Ersue
<mailto:[email protected]>
WG Chair: Bert Wijnen
<mailto:[email protected]>
Editor: Andy Bierman
<mailto:[email protected]>
Editor: Martin Bjorklund
<mailto:[email protected]>
YANG ver: 1.0
Deviated: no
Implement: yes
URI:
Revisions: 2012-02-22
Includes:
Imports: yang:ietf-yang-types
Typedefs: user-name-type
matchall-string-type
access-operations-type
group-name-type
action-type
node-instance-identifier
Idents:
Features:
Augments:
Deviation:
Data: container "nacm"
Print information about specific model part
Print information about a node:
> print -f info -P /ietf-netconf-acm:nacm/denied-operations ietf-netconf-acm
Leaf: denied-operations
Module: ietf-netconf-acm
Desc: Number of times since the server last restarted that a
protocol operation request was denied.
Reference:
Config: read-only
Status: current
Mandatory: yes
Type: zero-based-counter32
Units:
Default:
If-feats:
When:
Must:
Print detailed information about its type zero-based-counter32:
> print -f info -P type/ietf-netconf-acm:nacm/denied-operations ietf-netconf-acm
Base type: uint32
Range:
Superior: ietf-yang-types:zero-based-counter32
Print information about the typedef zero-based-counter32 it was derived from:
> print -f info -P typedef/zero-based-counter32 ietf-yang-types
Typedef: zero-based-counter32
Module: ietf-yang-types
Desc: The zero-based-counter32 type represents a counter32
that has the defined 'initial' value zero.
A schema node of this type will be set to zero (0) on creation
and will thereafter increase monotonically until it reaches
a maximum value of 2^32-1 (4294967295 decimal), when it
wraps around and starts increasing again from zero.
Provided that an application discovers a new schema node
of this type within the minimum time to wrap, it can use the
'initial' value as a delta. It is important for a management
station to be aware of this minimum time and the actual time
between polls, and to discard data if the actual time is too
long or there is no defined minimum time.
In the value set and its semantics, this type is equivalent
to the ZeroBasedCounter32 textual convention of the SMIv2.
Reference: RFC 4502: Remote Network Monitoring Management Information
Base Version 2
Status: current
Base type: uint32
Range:
Superior: counter32
Units:
Default: 0
Finally, print information about the typedef counter32 the other typedef zero-based-counter32 was derived from:
> print -f info -P typedef/counter32 ietf-yang-types
Typedef: counter32
Module: ietf-yang-types
Desc: The counter32 type represents a non-negative integer
that monotonically increases until it reaches a
maximum value of 2^32-1 (4294967295 decimal), when it
wraps around and starts increasing again from zero.
Counters have no defined 'initial' value, and thus, a
single value of a counter has (in general) no information
content. Discontinuities in the monotonically increasing
value normally occur at re-initialization of the
management system, and at other times as specified in the
description of a schema node using this type. If such
other times can occur, for example, the creation of
a schema node of type counter32 at times other than
re-initialization, then a corresponding schema node
should be defined, with an appropriate type, to indicate
the last discontinuity.
The counter32 type should not be used for configuration
schema nodes. A default statement SHOULD NOT be used in
combination with the type counter32.
In the value set and its semantics, this type is equivalent
to the Counter32 type of the SMIv2.
Reference: RFC 2578: Structure of Management Information Version 2
(SMIv2)
Status: current
Base type: uint32
Range:
Superior: uint32
Units:
Default:
Preparation:
> clear
> add ietf-netconf-acm.yang
Print all user-name elements that occure in data
Command and its output:
> xpath -e //ietf-netconf-acm:user-name data-acm.xml
Result:
Leaflist "user-name" (val: smith)
Leaflist "user-name" (val: smith)
Leaflist "user-name" (val: doe)
Print all data that satisfies condition
Command and its output:
> xpath -e //ietf-netconf-acm:user-name[text()="smith"] data-acm.xml
Result:
Leaflist "user-name" (val: smith)
Leaflist "user-name" (val: smith)
Preparation:
> clear
> add ietf-interfaces.yang
> add ietf-ip.yang
> add iana-if-type.yang
Note: This example also shows JSON output of the command.
Command and its output:
> feature -e * ietf-ip
> data -f json -t config data-ip.xml
{
"ietf-interfaces:interfaces": {
"interface": [
{
"name": "eth0",
"description": "Wire Connection",
"type": "iana-if-type:ethernetCsmacd",
"enabled": true,
"ietf-ip:ipv4": {
"address": [
{
"ip": "192.168.1.15",
"netmask": "255.255.255.0"
},
{
"ip": "192.168.1.10",
"netmask": "255.255.255.0"
}
]
}
}
]
}
}