Is it possible to set the mapIdentifier value from a variable for a KeyValueMapOperations policy?

[kristianjaeger]

Hello,

Is it possible to set the mapIdentifier value from a variable for a KeyValueMapOperations policy? This would be helpful so that folks could just have one KVM operations policy in a shared flow and not have to have one in each proxy. Thanks. Have a good weekend!

[sidd-harth]

AFAIk it is not possible to use dynamic/variable values in KVM mapIdentifier.

Why not use one KVM where you have all the configurations?

Use prefix to differentiate.

[kristianjaeger]

Thanks for the response. Yes, I was aware of that possibility. I was hoping to be able to have code reuse for the KeyValueMapOperations policy in the Shared Flow. It sounds like that's not currently possible though.

[dchiesa1]

You might be able to accomplish what you want; Just use the variable as part of the KEY, which is a dynamically computed composite value. The mapIdentifier remains fixed, but the key can vary.

<KeyValueMapOperations name='KVM-get1' mapIdentifier='nameOfMap'>
  <Scope>environment</Scope>
  <ExpiryTimeInSecs>300</ExpiryTimeInSecs>
  <Get assignTo='variable.to.set' >
    <Key>
      <Parameter ref='variable.containing.discriminator'/>
      <Parameter ref='variable.containing.original.key'/>
    </Key>
  </Get>
</KeyValueMapOperations>

[kristianjaeger]

Thanks! Great idea. I will try that. Cheers.

[praviningawale]

Hi Dino.

We are using this KeyValueMapOperations policy within a shared flow.

How can I solve then problem mentioned in this article?

If I call Shared Flow from Proxy P1, then I want to use mapIdentifier, say P1Identifier and when I call from proxy P2 I have to use P2Identifier

[dchiesa1]

I suppose you could use apiproxy.name as the discriminator.

<KeyValueMapOperations name='KVM-get1' mapIdentifier='nameOfMap'>
  <Scope>environment</Scope>
  <ExpiryTimeInSecs>300</ExpiryTimeInSecs>
  <Get assignTo='variable.to.set' >
    <Key>
      <Parameter ref='apiproxy.name'/>
      <Parameter ref='variable.containing.original.key'/>
    </Key>
  </Get>
</KeyValueMapOperations>

Is it as simple as that?

[Telstar]

It would be good if mapIdenfier can be set dynamically using variable. For example we don't want to load one kvm containing 100 entries (25 groups x 4 entries per group, with different prefix) again and again but only need 4 of them each time. Not efficient maintenance and performance wise. Ideally we should have 25 kvms, one for each group, then load the one we need by passing in group id/name in mapIdenfier field via a variable. Is this a valid use case?

[dchiesa1]

It would be good if mapIdenfier can be set dynamically using variable.

Thanks for that feedback.  I agree with you!

Since the original question and answer here, Apigee has added the ability to set the map identifier in a variable. The way to do it is omit the mapIdentifier attribute, and add a MapName element. The syntax looks like this;

<KeyValueMapOperations name='KVM-Get'>
  <Scope>environment</Scope>
  <ExpiryTimeInSecs>300</ExpiryTimeInSecs>
  <!-- Specify the mapname with a variable here -->
  <MapName ref='mapname'/>
  <Get assignTo="private.myvar">
    <Key>
      <Parameter ref='request.queryparam.key'/>
    </Key>
  </Get>
</KeyValueMapOperations>

Ideally we should have 25 kvms, one for each group, then load the one we need by passing in group id/name in mapIdenfier field via a variable. Is this a valid use case?

Maybe rethink that and use the group ID as a part of the KEY in the KVM. You don't need distinct KVMs for that purpose. The key in the KVM is designed to support your use case nicely. a "map" is just a named domain for the Key-Value-Map capability in Apigee. You don't need distinct "maps" just to segregate values. If you have 25 groups, and within those groups 4 different settings, you can store all 100 of those settings with distinct keys in a single map.  That seems like the easiest and most bueno thing to do.

Specify a composite key with multiple key parameters. Like this:

<KeyValueMapOperations name='KVM-Get'>
  <Scope>environment</Scope>
  <ExpiryTimeInSecs>300</ExpiryTimeInSecs>
  <MapName ref='mapname'/>
  <Get assignTo="private.myvar">
    <Key>
      <Parameter ref='groupid'/>
      <Parameter ref='settingid'/>
      <!-- add more parameters as you need them -->
    </Key>
  </Get>
</KeyValueMapOperations>

[Telstar]

That is exactly what we need. Great thanks @dchiesa1 !

[dchiesa1 · Accepted solution]

NEW ANSWER, 2021 September: YES

Since the original question and answer here, Apigee has added the ability to set the map identifier in a variable. The way to do it is omit the mapIdentifier attribute, and add a MapName element. The syntax looks like this:

<KeyValueMapOperations name='KVM-Get'>
  <Scope>environment</Scope>
  <ExpiryTimeInSecs>300</ExpiryTimeInSecs>
  <!-- specify the map name via a variable here -->
  <MapName ref='mapname'/>
  <Get assignTo="private.myvar">
    <Key>
      <Parameter ref='request.queryparam.key'/>
    </Key>
  </Get>
</KeyValueMapOperations>