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From Mark Payne <>
Subject Re: [DISCUSS] Extension Registry
Date Fri, 16 Nov 2018 15:41:50 GMT

Thanks for bringing that up. It's a good point that we need to keep in mind. As mentioned,
the NAR Maven Plugin will be generating the info necessary and putting it into the NAR. One
piece of information that it will gather is any Controller Service API's that are provided
by a given
implementation. So the registry will have this information. So the technical details are not
We do, however, need to ensure that we provide a good User Experience for such a thing. Perhaps
when you click to create a new Controller Service from a 'Configure' dialog we should have
a way to
jump to a 'remote registry browser' type of thing and download from there...

> On Nov 13, 2018, at 2:32 PM, Michael Moser <> wrote:
> I have thought about this in the past, too.  Here's a scenario where I
> could never really lay down an approach I was happy with.
> Consider that a NiFi user searches the NiFi registry and finds the PutMongo
> processor.  Registry knows the PutMongo processor is in the
> nifi-mongodb-nar, and through its Nar-Dependency-Id that it has a
> dependency on a controller service interface in
> nifi-mongodb-client-service-api-nar.  Great, the user can then download and
> install those two nars.  How would we then suggest that the user also needs
> a MongoDBClientService controller service implementation, such as that in
> the nifi-mongodb-services-nar?
> I'm not looking for an answer now, of course, but I just wanted to feed the
> discussion.
> Thanks,
> -- Mike
> On Tue, Nov 13, 2018 at 1:34 PM Bryan Bende <> wrote:
>> Mark,
>> I think there are a couple of ways that could be solved, but
>> ultimately it would be up to how the users choose to setup/manage the
>> registry, or registries.
>> The NiFi Registry security model is based around permissions to
>> buckets (read/write), and all versioned items belong to a bucket. So
>> you could think of each bucket as a mini extension repository for
>> which you can control access to specific users and groups, so there
>> could be a bucket of extensions for each of the NiFi instances in your
>> example. There can also be multiple registry instances registered with
>> a given NiFi so extensions can be pulled from multiple registries.
>> The extensions an instance needs is based on the flows it is running,
>> the flows already have specific bundle coordinates for every component
>> in the flow. You can think of it similar to Maven where you declared a
>> dependency on library foo and the build goes out and gets it for you,
>> in this case it is a flow that declares a dependency on a bundle.
>> Mike,
>> Bundles would need to be uploaded to NiFi Registry (to a specific
>> bucket) as part of some TBD release process. At a minimum I was
>> envisioning NiFi CLI commands that can be pointed to a file or a
>> directory and upload the given bundles to registry. There could be
>> other options as well, possibly through a Maven plugin to release
>> directly into registry, or possibly to have a type of extension in
>> NiFi Registry that actually points to an external location, i.e. all
>> the NARs that end up in Maven central could somehow be imported into
>> NiFi Registry, but with pointers back to the content which actually
>> comes from Maven central. Lot of things to figure out here.
>> -Bryan
>> On Tue, Nov 13, 2018 at 1:16 PM Joe Witt <> wrote:
>>> Group selection based on tag names for bundles could probably do that.
>>> Meaning it could be a sorting/filtering mechanism in the NiFi/Registry
>>> interface perhaps.  Will be good to consider that UX as that
>>> progresses.
>>> As far as the different environments NiFi instances would certainly be
>>> able to load only referenced Nars for versioned flows so you'll get
>>> the optimal set (at runtime) automatically.  Very powerful.
>>> On Tue, Nov 13, 2018 at 1:12 PM Mark Bean <> wrote:
>>>> Joe,
>>>> I envision the Registry being able to provide a subset of NARs
>> required for
>>>> a specific NiFi instance. The user may have a relatively small set of
>> NARs
>>>> required for a NiFi used for basic routing/distribution, and a
>> different
>>>> more extensive set of NARs required for a more robust NiFi instance
>> which
>>>> performs various forms of processing/transformations. The grouping I am
>>>> describing would be a way to select multiple NARs required for a
>> specific
>>>> NiFi instance.
>>>> Expanding the scenario a little farther, suppose an integration/test
>>>> environment defines the group. Then, the production environment can
>> use the
>>>> group definition to pull (or ensure it possesses) only the relevant
>> NARs
>>>> necessary.
>>>> -Mark
>>>> On Tue, Nov 13, 2018 at 1:00 PM Joe Witt <> wrote:
>>>>> Mark
>>>>> Can you describe your use case from the user perspective both for the
>>>>> entity that would upload the items and demarcate them as a group as
>>>>> well as the user that would consume those bundles?
>>>>> I ask because the point here is that nars are themselves a 'group' in
>>>>> that they are a logical/contained grouping of extensions.  These can
>>>>> have relationships to other nars as we know.  And flows are designed
>>>>> against specific components that come from certain nars for which we
>>>>> know the precise coordinates.  When importing flows that depend on
>>>>> these the system will be able to automatically acquire all that it
>>>>> needs.
>>>>> Thanks
>>>>> On Tue, Nov 13, 2018 at 12:57 PM Mark Bean <>
>> wrote:
>>>>>> I would like to see a "group" capability in the Registry for NAR
>> bundles.
>>>>>> Then, users can create their own customized grouping of relevant
>> NARs.
>>>>>> Managing bundles one at a time will become tedious.
>>>>>> Thanks,
>>>>>> Mark
>>>>>> On Tue, Nov 13, 2018 at 12:48 PM Joe Witt <>
>> wrote:
>>>>>>> Sivaprasanna - yes absolutely.  That is the core point I think
>>>>>>> Bryan's first bullet under the 'NiFi' section.
>>>>>>> On Tue, Nov 13, 2018 at 12:47 PM Sivaprasanna <
>>>>>>> wrote:
>>>>>>>> One quick question. With the extension registry, my
>> understanding is
>>>>> that
>>>>>>>> we would try to reduce the overall NiFi size by offloading
>> certain
>>>>>>> existing
>>>>>>>> NAR bundles to the extension registry. So are we expecting
>>>>> extension
>>>>>>>> registry to also come up with the ability/mechanism that
>> an
>>>>> user to
>>>>>>>> download these bundles ?
>>>>>>>> -
>>>>>>>> Sivaprasanna
>>>>>>>> On Tue, 13 Nov 2018 at 11:07 PM, Joe Witt <>
>>>>> wrote:
>>>>>>>>> Bryan
>>>>>>>>> Very exciting to see this under way!!!  We desperately
>> to get
>>>>> our
>>>>>>>>> core nifi build size way down and make it far easier
>> people to
>>>>>>>>> contribute new processors.  We have a long line of
>> extensions that
>>>>>>>>> could be really useful/valuable and this will help unlock
>> that
>>>>> while
>>>>>>>>> improving the user experience tremendously.
>>>>>>>>> For the doc/concerns noted above we should also add/mention
>> that
>>>>> the
>>>>>>>>> relationship between nars (dependencies between nars
>>>>>>>>> apis/controller services/parent nars/etc..) we want to
>> a way
>>>>> to
>>>>>>>>> manage/show that or a user experience for it.  Maybe
not a
>> day-1
>>>>> thing
>>>>>>>>> but important to call out.
>>>>>>>>> Thanks!
>>>>>>>>> Joe
>>>>>>>>> On Tue, Nov 13, 2018 at 12:22 PM Bryan Bende <
>>>>> wrote:
>>>>>>>>>> All,
>>>>>>>>>> We've needed the elusive extension registry for quite
>> time
>>>>> now,
>>>>>>>>>> and with NiFi Registry I think we are in a good place
>> make
>>>>> some
>>>>>>>>>> progress in this area.
>>>>>>>>>> I've started looking into adding "extension bundles"
>> NiFi
>>>>> Registry
>>>>>>>>>> as the next type of versioned item, along side the
>>>>> versioned
>>>>>>>>>> flows, and I wanted to take a minute to outline how
>> approach
>>>>>>>>>> could work before getting too far into it.
>>>>>>>>>> Also, I'd like to focus this discussion on the design
>>>>>>>>>> functionality of the extension registry, and not
on how the
>>>>> community
>>>>>>>>>> is going to use it. Topics like hosting a central
>>>>> changing
>>>>>>>>>> the build process, restructuring the git repo, releasing
>> NARs,
>>>>> etc,
>>>>>>>>>> are all important topics, but first we need an extension
>> registry
>>>>>>>>>> before we can do any of that :)
>>>>>>>>>> Here is a high-level description of what needs to
>> done...
>>>>>>>>>> NiFi Registry
>>>>>>>>>> - Add a new type of item called an extension bundle,
>> each
>>>>>>> bundle
>>>>>>>>>> can contain one ore extensions or APIs
>>>>>>>>>> - Support bundles for traditional NiFi (aka NARs)
and also
>>>>> bundles
>>>>>>> for
>>>>>>>>>> MiNiFi CPP
>>>>>>>>>> - Ability to upload the binary artifact for a bundle
>> extract
>>>>> the
>>>>>>>>>> metadata about the bundle, and metadata about the
>> extensions
>>>>>>> contained
>>>>>>>>>> in the bundle (more on this later)
>>>>>>>>>> - Provide a pluggable storage provider for saving
>> content of
>>>>> each
>>>>>>>>>> extension bundle so that we can have different
>> implementations
>>>>> like
>>>>>>>>>> local fileysystem, S3, and other object stores
>>>>>>>>>> - Provide a REST API for listing and retrieving available
>>>>> bundles,
>>>>>>>>>> integrate this into the registry Java client and
>>>>>>>>>> NAR Maven Plugin
>>>>>>>>>> - Generate a descriptor for each component in the
>> which will
>>>>>>>>>> provide information like the description, tags, restricted
>> or
>>>>> not,
>>>>>>>>>> etc.
>>>>>>>>>> - These descriptors will be parsed by NiFi Registry
when a
>> NAR is
>>>>>>>>>> being uploaded so that NiFi Registry will know about
>>>>> extensions
>>>>>>>>>> contained with in the NAR
>>>>>>>>>> NiFi
>>>>>>>>>> - Provide some type of extension manager experience
>> users
>>>>> can
>>>>>>>>>> search, browse, & install bundles that are available
>> any of
>>>>> the
>>>>>>>>>> registry clients that have been defined
>>>>>>>>>> - Introduce a new security policy to control which
>> are
>>>>> allowed
>>>>>>>>>> to access the extension manager
>>>>>>>>>> - Installing a bundle should load the NAR and make
>> extensions
>>>>>>>>>> available leveraging the recent work done to auto-load
>> NARs
>>>>>>>>>> - Importing versioned flows from registry should
>> an easy
>>>>> way
>>>>>>>>>> to install bundles that are required by the flow,
>> missing
>>>>> from
>>>>>>> the
>>>>>>>>>> local NiFi instance
>>>>>>>>>> If anyone has any thoughts or concerns about this
>>>>> please
>>>>>>> let
>>>>>>>>> me know.
>>>>>>>>>> Thanks,
>>>>>>>>>> Bryan

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