apigee statistic collector/custom reports not working - statistics

Question

I'm stuck at generating custom reports using Statistics Collector.
My scenario,
I have an BaaS DB with a collection named "icustomer" which has few name/value pair's.
I created a proxy(icustomer) to display an specific Customer(Resource name- specificcust) depending on unique "cust_id".
For Specific Customer I did "extract variable and assign variable policies" which is working fine.
Now to get custom reports I again added an Extract Variable policy to extract cust_id from JSON Path and then added and Statistic Collector policy to get stats.
Then I created an new report from Analytics and saved it. But reports aren't generated. All I get is "NO_ID" report.
Where did I go wrong?
Proxy Endpoint Code
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ProxyEndpoint name="default">
<Description/>
<PreFlow name="PreFlow">
<Request/>
<Response/>
</PreFlow>
<Flows>
<Flow name="specficcust">
<Description/>
<Request/>
<Response/>
<Condition>(proxy.pathsuffix MatchesPath "/{cust_id}") and (request.verb = "GET")</Condition>
</Flow>
</Flows>
<PostFlow name="PostFlow">
<Request/>
<Response/>
</PostFlow>
<HTTPProxyConnection>
<BasePath>/icustomer</BasePath>
<VirtualHost>default</VirtualHost>
<VirtualHost>secure</VirtualHost>
</HTTPProxyConnection>
<RouteRule name="default">
<TargetEndpoint>default</TargetEndpoint>
</RouteRule>
</ProxyEndpoint>
Target Endpoint Code
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<TargetEndpoint name="default">
<Description/>
<PreFlow name="PreFlow">
<Request/>
<Response/>
</PreFlow>
<Flows>
<Flow name="specficcust">
<Description/>
<Request>
<Step>
<FaultRules/>
<Name>Extract-Variables-1</Name>
</Step>
<Step>
<FaultRules/>
<Name>Assign-Message-1</Name>
</Step>
</Request>
<Condition>(proxy.pathsuffix MatchesPath "/{cust_id}") and (request.verb = "GET")</Condition>
<Response/>
</Flow>
</Flows>
<PostFlow name="PostFlow">
<Response>
<Step>
<FaultRules/>
<Name>Extracting-for-Stats</Name>
</Step>
<Step>
<FaultRules/>
<Name>Statistics-Collector-1</Name>
</Step>
</Response>
<Request/>
</PostFlow>
<HTTPTargetConnection>
<URL>https://api.usergrid.com/siddharth1/sandbox/icustomer</URL>
</HTTPTargetConnection>
</TargetEndpoint>
Extracting for Stats code-
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ExtractVariables async="false" continueOnError="false" enabled="true" name="Extracting-for-Stats">
<DisplayName>Extracting for Stats</DisplayName>
<FaultRules/>
<Properties/>
<IgnoreUnresolvedVariables>true</IgnoreUnresolvedVariables>
<JSONPayload>
<Variable name="customer_id">
<JSONPath>$.entities[0].cust_id</JSONPath>
</Variable>
</JSONPayload>
<Source clearPayload="false">response</Source>
<VariablePrefix>apigee</VariablePrefix>
</ExtractVariables>
Statistics Collector code-
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<StatisticsCollector async="false" continueOnError="false" enabled="true" name="Statistics-Collector-1">
<DisplayName>Statistics Collector 1</DisplayName>
<FaultRules/>
<Properties/>
<Statistics>
<Statistic name="test_cust_id" ref="customer_id" type="STRING">NO_ID</Statistic>
</Statistics>
</StatisticsCollector>

Answer 1

Your ExtractVariables specifies a VariablePrefix of "apigee". I would expect the extracted field to be accessible from apigee.customer_id instead of just customer_id, which would return null in the StatisticsCollector check. I think that's why you are getting your default "NO_ID".