Unable to import templates in Nifi

[#1]

Hi Team, 
We have a usescase wherein we want to import the templates directly into nifi canvas using the rest apis provided by nifi we are hitting with the below error. If anyone faced this issue previously please assisst.

we are able to upload, download but import is not working 

To get the token

bearer=$(curl 'https://nifi-host:nifi-port/nifi-api/access/token' --data 'username=username&password=password' --compressed --insecure)

To import the template 

curl -i -X -k POST -H "Content-Type: application/xml" -H "Authorization: Bearer $bearer" -F "template=@/root/tmp/template.xml" https://nifi-host:nifi-port/nifi-api/process-groups/processor-group-id/templates/import 

Nifi version - 1.8.0.3.3.1.0-10

error - HTTP 400 Bad Request

Thanks 

[#2]

@broobalaji, Welcome to our community! To help you get the best possible answer, I have tagged in our NiFi experts @MattWho  @SAMSAL @TimothySpann @steven-matison @ckumar   who may be able to assist you further.

Please feel free to provide any additional information or details about your query, and we hope that you will find a satisfactory solution to your question.

[#3]

If you have  to load the new template from the filesystem/local to the NiFi cluster, the following API call should be made with POST method 

nifi-api/process-groups/{pg-id}/templates/upload

Thank you

[#4]

Hi @ckumar 
Is there any way (api call) to directly import the templates into the nifi canvas

/process-groups/{id}/templates/import 

we got this api call in the nifi api doc

doc - https://nifi.apache.org/docs/nifi-docs/rest-api/index.html

This is not working for us 

Thanks 

[#5 · Accepted solution]

 The first step is to create a template, which can be  created within in NiFi cluster from another flow or uploaded from the filesystem, this action will load the templates under 

/nifi-api/flow/templates

Then use the below one to create a process group from a template. 
/process-groups/{id}/template-instance

import is not the right API call, you can verify this from from web developer tool doing the same actions from UI. 

[#6]

Thanks we were able to import the templates using the api calls

curl -X POST -H "Content-Type: multipart/form-data" -H "Authorization: Bearer $bearer" -F "template=@/root/api_testing/template.xml" https://host-ip:host-port/nifi-api/process-groups/process-group-id/templates/upload -k

First we need to upload the template from local as it generates a id for the template which we can use for importing the template into the canvas 

For importing the template

curl -i -X POST -H "Content-Type: application/json" -H "Authorization: Bearer $bearer" -d '{"templateId":"template-id","originX":100,"originY":100}'  https://host-ip:host-port/nifi-api/process-groups/process-group-id/template-instance -k

[#7]

@broobalaji 

HDF 1.8.0.3.3.1.0-10 was released way back in 2017.  I strongly recommend upgrading to a much newer release of CFM.  

NiFi Templates have been deprecated and are completely removed as of Apache NiFi 2.x releases.  Apache NiFi deprecated templates for a number of reasons:

1. Templates uploaded to NiFi (even if not instantiated/imported to the NiFi canvas reside within NiFi's heap memory space) 
2. Large uploaded templates or many uploaded templates can have a substantial impact on NiFi performance because of the amount of heap they can consume.  Simply increasing the size of NiFi's heap is also not the best solution to that heap usage as large heaps just lend themselves to longer stop-the-world garbage collections with the JVM. 
3. Apache NiFi deprecated and moved away from using xml based flow in favor of json flow definitions around the Apache NiFi 1.16 time frame.  

Flow definitions (JSON files) can exported and imported without uploading them in to heap memory within NiFi.

The above info aside....
It is best to use the developer tools available in your web browser to inspect/capture the rest-api call being made when you perform the same steps directly via the NiFi UI.  This makes it easy to understand the calls that need to be made in your automation.  I also encourage you if you continue to use templates to upload, import to UI, and then delete the uploaded template to minimize heap impact.

Thanks,
Matt