Example: EntityFromIfString.stch

Use this topic to understand how entity retrieval stitchers work.

The EntityFromIfString.stch stitcher looks up an interface based on a main node entityName and a string, which is expected to be the ifName, ifDescr or ifAlias of the interface. This returns the interface entity, if found in NCIM cache.

Table 1. Line-by-line description of the EntityFromIfString.stch stitcher
Line numbers	Description
3-7	This stitcher is invoked by another stitcher, usually a topology lookup stitcher.
11-12	Read the input arguments from the invoking stitcher.
16-27	Set up an SQL query to retrieve an entity data record for an interface based on a main node entityName and a string, which is expected to be the ifName, ifDescr or ifAlias of the interface.
30	Use the RetrieveSingleOQL() stitcher rule to run the query and retrieve the entity data record for the interface.
32	Pass the result of the entity lookup back to the invoking stitcher.

UserDefinedStitcher
{
    StitcherTrigger
    {
        // There is no trigger, as this is explicitly called from
        // other stitchers.
    }

    StitcherRules
    {
        text mainNodeEntityName = ARG_1;
        text ifString = ARG_2;

        Record entity;

        text ifStringQuery = 
                "select * from ncimCache.entityData 
                 where 
                 ENTITYTYPE = 2
                 and
                 BASENAME = eval(text, '$mainNodeEntityName')
                 and
                 ( interface->IFNAME = eval(text, '$ifString')
                   or 
                   interface->IFDESCR = eval(text, '$ifString')
                   or
                   interface->IFALIAS = eval(text, '$ifString') );";


        entity = RetrieveSingleOQL( ifStringQuery );

        SetReturnValue( entity );
    }
}