Page History

Initial Findings

It is found that the current Patch operation in CPS core can only update value of one data tree leaf nodes under a container node at a time. So if there are multiple data trees under an anchor and a Patch is performed on all the data trees using root node xPath "/" then only the first data tree gets updated and the remaining data trees remain as it is,

Based on the above outcome, another test to update individual data trees was preformed, and it was found that when a specific data tree is being updated using its specific xPath none of the data trees get updated and a 400 BAD REQUEST is received.

Decisions

...

Issues & Decisions:

JSON Data Stored in CPS DB using POST operation.

The following JSON data was first stored in CPS DB, then to test the GET operation:

{
  "multiple-data-tree:interface-A": {
    "host-name": "host",
    "interface": [
      {
        "name": "Interface-A",
        "address": "10.10.10.1",
        "subnet-mask": "255.255.255.0",
        "enabled": false
      }
    ],
    "domain": "false"
  },
  "multiple-data-tree:interface-B": {
    "interface": [
      {
        "name": "Interface-B",
        "address": "10.10.10.1",
        "subnet-mask": "255.255.255.0"
      }
    ]
  }
}

Analysis of Patch operation (Update node leaves)

Currently after multiple data trees are stored in CPS DB. On performing the Patch operation on the same data, with root node xpath set as root "/", the first data tree is only updated by the Patch operation. To test this following scenarios were performed:

1. Updating all data trees under an anchor with root node xPath "/"

   Code Block
   title CURL request to update

   all code

   multiple leaves across multiple data trees collapse

   true

   curl --location --request PATCH 'http://localhost:8080/cps/api/v1/dataspaces/testDataspace/anchors/sample/nodes?xpath=%2F' --header 'Content-Type: application/json' --header 'Accept: application/json' --header 'Authorization: Basic Y3BzdXNlcjpjcHNyMGNrcyE=' --header 'Cookie: JSESSIONID=node0iyclt1syzfqj28jzo5qc5gks1.node0' \ --data '{ "multiple-data-tree:interface-A": { "host-name": "host-A", //value to be updated "interface": [ { "name": "Interface-A", "address": "10.10.10.100", //Updated Value "subnet-mask": "255.255.255.25",         "enabled": false } ], "domain": "true" }, "multiple-data-tree:interface-B": { "interface": [ { "name": "Interface-B", "address": "10.10.10.1100100",     //value to be updated         "subnet-mask": "255.255.255.0"   //value to be updated       } ] } }'

   
   

   code

   Code Block
   title Response: 500 Server Error
   collapse true
   { "status": "500 INTERNAL_SERVER_ERROR", "message": "could not execute statement; SQL [n/a]; nested exception is org.hibernate.exception.DataException: could not execute statement", "details": "Check logs for details." }

   Reason: The following scenario would fail because CPS Patch operation only supports updating multiple leaves under one container node at a time. And here when we try to update multiple leaves present in two different containers the operations fails. 
   
   

   Code Block
   title On performing Get operation we get the following JSON data

   code

   , here none of the leaves are updated collapse true

   [ { "int:interface-A": { "domain": "false", "host-name": "host", "interface": [ { "name": "Interface-A", "address": "10.10.10.1", "enabled": false, "subnet-mask": "255.255.255.0" } ] } }, { "int:interface-B": { "interface": [ { "name": "Interface-B", "address": "10.10.10.1", "subnet-mask": "255.255.255.0" } ] } } ]

   
   

2. Updating the first data treedata trees individually, leads to successful updation
   When updating multiple leaves present under individual data nodes the operation successfully executes.

   Code Block
   title CURL request to update

   first data tree

   leaves under container data node collapse true

   code

   curl --location --request PATCH 'http://localhost:8080/cps/api/v1/dataspaces/testDataspace/anchors/sample/nodes?xpath=%2Finterface-A%2F' \ --header 'Content-Type: application/json' --header 'Accept: application/json' --header 'Authorization: Basic Y3BzdXNlcjpjcHNyMGNrcyE=' --header 'Cookie: JSESSIONID=node0iyclt1syzfqj28jzo5qc5gks1.node0' \ --data '{ "int:interface-A": { "namedomain": "Interface-Atrue", //value to be updated "addresshost-name": "10.10.10.200", Host-A" //value to "enabled": true, "subnet-mask": "255.255.255.0" be updated } }'

   Response 200 OK
   

   code

   Code Block
   title Updated data after making get request
   collapse true
   [ { "int:interface-A": { "domain": "falsetrue", //updated "host-name": "hostHost-A", //updated "interface": [ { "name": "Interface-A", "address": "10.10.10.200", "enabled": true, "subnet-mask": "255.255.255.0" } ] } } ]

   Updating the second data tree

   
   

   Code Block
   title CURL request to update

   second data treecode

   leaves of one list item in a list data node collapse true

   curl --location --request PATCH 'http://localhost:8080/cps/api/v1/dataspaces/testDataspace/anchors/sample/nodes?xpath=%2Finterface-B' \ --header 'Content-Type: application/json' --header 'Accept: application/json' --header 'Authorization: Basic Y3BzdXNlcjpjcHNyMGNrcyE=' --header 'Cookie: JSESSIONID=node0iyclt1syzfqj28jzo5qc5gks1.node0' \ --data '{ "int:interface": { "name": "Interface-B", "address": "10.10.10.200", //value to be updated "subnet-mask": "255.255.255.10" //value to be updated } }'

   Response 200 OK
   

   code

   Code Block
   title Updated data after making get request
   collapse true
   [ { "int:interface-B": { "interface": [ { "name": "Interface-B", "address": "10.10.10.200", //updated "subnet-mask": "255.255.255.10" //updated } ] } } ]

   
   

Inconsistencies with Patch Operation

When updating multiple data trees with only leaf nodes

Assuming the following data is in the data base, having one leaf in each data tree

{
  "first-container": {
    "a-leaf": "a-value"
  },
  "last-container": {
    "x-leaf": "x-value"
  }
}

An update operation is performed on both data trees as follows:

curl --location --request PATCH 'http://localhost:8080/cps/api/v1/dataspaces/testDataspace/anchors/multipleDataTree/nodes?xpath=%2F' --header 'Content-Type: application/json' --header 'Accept: application/json' --header 'Authorization: Basic Y3BzdXNlcjpjcHNyMGNrcyE=' --header 'Cookie: JSESSIONID=node0kglnliqz1tzc1g0x6opgrphei0.node0' \
--data '{
  "first-container": {
    "a-leaf": "a-new-value"
  },
  "last-container": {
    "x-leaf": "x-new-value"
  }
}'

On performing a get operation, it is noticed that only first data tree gets updated

[
  {
    "multiple-data-tree:last-container": {
      "x-leaf": "x-new-value"
    }
  },
  {
    "multiple-data-tree:first-container": {
      "a-leaf": "a-value"
    }
  }
]

When updating multiple list items under a list node, returns Status 200 but list data is not updated

(Note: This following finding was identified as an issue with list-nodes and not multiple data nodes. It is documented separately CPS-1383: Investigate CPS-Path for modifications of multiple fragments under an anchor.)