More information can be found in the source code of ncmount sample
app + on wiki:
https://wiki-archive.opendaylight.org/view/Controller_Core_Functionality_Tutorials:Tutorials:Netconf_Mount
+
+Reading selected fields from device
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Using NETCONF DOM API it is also possible to read only selected fields
+from NETCONF device. NETCONF mountpoint exposes 2 services that provides
+this functionality:
+
+a. **NetconfDataTreeService** - It provides overloaded methods 'get'
+ (operational data) and 'getConfig' (configuration data)
+ with 'List<YangInstanceIdentifier> fields' parameters. This service
+ should be used if transaction properties are not required.
+b. **NetconfDOMDataBrokerFieldsExtension** - It implements DOMDataBroker
+ interface - provides the same transaction functionality plus method
+ for reading of data with selected fields: read(LogicalDatastoreType,
+ YangInstanceIdentifier, List<YangInstanceIdentifier>).
+ Instance of NetconfDOMDataBrokerFieldsExtension can be obtained
+ using 'getExtensions()' method on the DOMDataBroker instance.
+
+'List<YangInstanceIdentifier> fields' parameter specifies list of paths
+that are read from device using subtree filtering. These paths must be
+relative to parent path - returned data follows schema of the last path
+argument of parent path.
+
+**Mechanics**
+
+* parent path: /a/b/c
+* fields: [/x/y; /w/z]
+
+NETCONF server will read data on following paths:
+* /a/b/c/x/y
+* /a/b/c/w/z
+
+And place read data under /a/b/c path - thus returned data will have
+following structure:
+
+.. code-block::
+
+ c: {
+ x: {
+ y: {
+ // data ...
+ }
+ }
+ w: {
+ z: {
+ // data ...
+ }
+ }
+ }
+
+From the view of DOM API, YangInstanceIdentifier (first parameter) represents
+the parent path, and List<YangInstanceIdentifier> represents list of selected
+fields.
+
+**Example: using NetconfDataTreeService**
+
+The following method demonstrates reading of 2 fields under parent list 'l1':
+
+* parent path: /c1/l1
+* fields (leaves 'x1' and 'x2'): [/c2/x1, /c2/l2/x2]
+
+Result will contain whole MapNode with possibly multiple MapEntryNode-s that
+contain only keys of list elements and selected fields.
+
+.. code-block:: java
+
+ public void readData(final DOMMountPoint mountPoint) {
+ final NetconfDataTreeService dataTreeService = mountPoint.getService(NetconfDataTreeService.class).get();
+
+ final YangInstanceIdentifier parentPath = YangInstanceIdentifier.builder()
+ .node(CONTAINER_C1_NI) // container 'c1' (root element)
+ .node(LIST_L1_NI) // list 'l1' placed under container 'c1'
+ .build();
+ final YangInstanceIdentifier leafX1Field = YangInstanceIdentifier.builder()
+ .node(CONTAINER_C2_NI) // container 'c2' placed under list 'l1'
+ .node(LEAF_X1_NI) // leaf 'x1' placed under container 'c2'
+ .build();
+ final YangInstanceIdentifier leafX2Field = YangInstanceIdentifier.builder()
+ .node(CONTAINER_C2_NI) // container 'c2' placed under list 'l1'
+ .node(NESTED_LIST_L2_NI) // list 'l2' placed under container 'c2'
+ .node(LEAF_X2_NI) // leaf 'x2' placed under list 'l2'
+ .build();
+
+ final ListenableFuture<Optional<NormalizedNode<?, ?>>> config = dataTreeService.getConfig(
+ parentPath, Lists.newArrayList(leafX1Field, leafX2Field));
+
+ Futures.addCallback(config, new FutureCallback<Optional<NormalizedNode<?, ?>>>() {
+ @Override
+ public void onSuccess(@Nullable final Optional<NormalizedNode<?, ?>> normalizedNode) {
+ normalizedNode.ifPresent(node -> LOG.info("Read data: {}", NormalizedNodes.toStringTree(node)));
+ /*
+ We expect data with following structure:
+ l1: [
+ {
+ key-l1: "k1",
+ c2: {
+ x1: 10,
+ l2: [
+ {
+ key-l2: 1,
+ x2: "foo"
+ },
+ ...
+ ]
+ }
+ },
+ ...
+ ]
+ */
+ }
+
+ @Override
+ public void onFailure(final Throwable throwable) {
+ LOG.error("Failed to read data: {}", parentPath, throwable);
+ }
+ });
+ }
+
+**Example: using NetconfDOMDataBrokerFieldsExtension**
+
+The following method demonstrates reading of 2 fields under parent
+container 'c1':
+
+* parent path: /c1
+* fields (leaf-list 'll1 'and container 'c2'): [/ll1, /l1=k1/c2]
+
+Result will contain ContainerNode with identifier 'c1' and children
+nodes (if they are present) of type LeafSetNode and MapNode.
+
+.. code-block:: java
+
+ public void readData(final DOMMountPoint mountPoint) {
+ final DOMDataBroker domDataBroker = mountPoint.getService(DOMDataBroker.class).get();
+ final NetconfDOMDataBrokerFieldsExtension domFieldsDataBroker = domDataBroker.getExtensions().getInstance(
+ NetconfDOMDataBrokerFieldsExtension.class);
+
+ final YangInstanceIdentifier parentPath = YangInstanceIdentifier.builder()
+ .node(CONTAINER_C1_NI) // container 'c1' (root element)
+ .build();
+ final YangInstanceIdentifier ll1Field = YangInstanceIdentifier.builder()
+ .node(LEAF_LIST_LL1_NI) // leaf-list 'll1' placed under container 'c1'
+ .build();
+ final YangInstanceIdentifier c2Field = YangInstanceIdentifier.builder()
+ .node(LIST_L1_NI) // list 'l1' placed under container 'c1'
+ .nodeWithKey(LIST_L1_QN, LIST_L1_KEY_QN, "k1") // specific list entry with key value 'k1'
+ .node(CONTAINER_C2_NI) // container 'c2' placed under container 'c1'
+ .build();
+
+ final FluentFuture<Optional<NormalizedNode<?, ?>>> data;
+ try (NetconfDOMFieldsReadTransaction roTx = domFieldsDataBroker.newReadOnlyTransaction()) {
+ data = roTx.read(LogicalDatastoreType.CONFIGURATION, parentPath, Lists.newArrayList(ll1Field, c2Field));
+ }
+
+ data.addCallback(new FutureCallback<>() {
+ @Override
+ public void onSuccess(@Nullable final Optional<NormalizedNode<?, ?>> normalizedNode) {
+ normalizedNode.ifPresent(node -> LOG.info("Read data: {}", NormalizedNodes.toStringTree(node)));
+ /*
+ We expect data with following structure:
+ c1: {
+ ll1: [...],
+ l1: [
+ {
+ l1-key: "k1",
+ c2: {
+ // data ...
+ }
+ }
+ ]
+ }
+ */
+ }
+
+ @Override
+ public void onFailure(final Throwable throwable) {
+ LOG.error("Failed to read data: {}", parentPath, throwable);
+ }
+ }, MoreExecutors.directExecutor());
+ }
Code Review / netconf.git / blobdiff