Re: Facing issue with Lookup Cache miss

sawantprajact · 06-01-2020 03:27 AM

Hi Greetings,

I'm trying to implement caching with apigee provided policies (populate and lookup cache) and stucked with one peculiar issue with lookup-cache.

Say for example, my first api request is working as expected but from the second/third api-request I start to getting this `cache-hit: false` issue. But, if I resend/refresh the UI, it gets me the expected data from cache.

Here is my populate-cache policy in 'getUserInfo' proxy attached to ProxyEndpoint:

<populatecache async="false" continueonerror="false" enabled="true" name="PC-StoreUserInfo">
	<displayname>PC-StoreUserInfo</displayname>
	<properties></properties>
	<cachekey>
		<prefix>user_info</prefix>
		<keyfragment ref="app_enduser"></keyfragment>
	</cachekey>
	<scope>Exclusive</scope>
	<expirysettings>
		<timeoutinseconds>3600</timeoutinseconds>
	</expirysettings>
	<source>response.content</Source>
</populatecache>

and here is my Lookup cache policy from 'sampleSharedFlow' Sharedflow:

<lookupcache async="false" continueonerror="false" enabled="true" name="LC-GetUserInfoFromCache">
	<displayname>LC-GetUserInfoFromCache</displayname>
	<properties></properties>
	<cachekey>
		<prefix>user_info</prefix>
		<keyfragment ref="app_enduser"></keyfragment>
	</cachekey>
	<scope>Exclusive</scope>
	<assignto>userDetail</assignto>
</lookupcache>

(sorry can't share the trace session):

lookupcache.LC-GetUserInfoFromCache.fault.name
type	LookupCacheExecution
enforcement	request
stepDefinition-continueOnError	false
stepDefinition-displayName	LC-GetUserInfoFromCache
stepDefinition-name	LC-GetUserInfoFromCache
stepDefinition-enabled	true
result	true
lookupcache.LC-GetUserInfoFromCache.failed	false
lookupcache.LC-GetUserInfoFromCache.assignto	userDetail
lookupcache.LC-GetUserInfoFromCache.isEncrypted	false
lookupcache.LC-GetUserInfoFromCache.cachekey	user_info__ttyu@yopmail.com
lookupcache.LC-GetUserInfoFromCache.cachename	example__dev
lookupcache.LC-GetUserInfoFromCache.cachehit	false
lookupcache.LC-GetUserInfoFromCache.fault.cause

What might be the possible cause of this cachehit false? where on reload/resend of the same request it gets the desired data from cache.

Thanks

dchiesa1

Can you check this answer and see if this is your experience?

The short summary is that it's possible you're seeing a bug in the Trace/DebugSession capability. And in fact the result of the LookupCache is a success, not a failure, but the trace shows it as a failure (cachehit = false).

In which case the resolution is ... ignore or work-around the Trace bug, and just keep going with your API Proxy development.

sawantprajact

Hi @Dino-at-Google,

First of all thanks for your time.

As per that link and your short description on the same "result of the LookupCache is a success, not a failure, but the trace shows it as a failure".

Does that mean my '<assignto>userDetail</assignto>' tag will store the resulting data into 'userDetail'?
What is the expected outcome of this variable incase of these scenario?

Because down the line i'm using JS-policy to manipulate this variable (where i expect this userDetail tobe always present) and make a api-call and i don't get any value in 'userDetail' variable.

Thanks