Apache Nifi - Adding attributes as newlines FlowFilw content

[#1]

Hi,

I have a scenario where My GetHTTP processor gets a JSON of system health metrics. I extract the attributes from the Json to essentially extract the desired metrics that I want to display on a Graph.

Input: Suppose following attributes I extracted from Json using EvaluateJSONPath processor:

metric1='<myconmapy>.<metric1> <value> <timestamp>'

metric2='<myconmapy>.<metric2> <value> <timestamp>'

metric3='<myconmapy>.<metric3> <value> <timestamp>'

Output: I want to convert all the above mentioned attributes/metrics as lines of FlowFile content, such that one FlowFile content will look like following (each line contains an attribute value):

<myconmapy>.<metric1> <value> <timestamp>

<myconmapy>.<metric2> <value> <timestamp>

<myconmapy>.<metric3> <value> <timestamp>

Is there a way to achieve the above mentioned Output using Nifi processors?

Thanks

[#2 · Accepted solution]

Yes, use a ReplaceText processor and NiFi's Expression Language syntax to reference your attributes and construct the content line. Tip: switch the evaluation mode for ReplaceText to 'Always Replace' as an optimization for your use case.

https://nifi.apache.org/docs/nifi-docs/components/org.apache.nifi.processors.standard.ReplaceText/in...

https://nifi.apache.org/docs/nifi-docs/html/expression-language-guide.html

[#3]

Awesome, I solved it by using the append('\n') for attribute:

${m1:append('\n')}${m2:append('\n')}${m3}

Thanks a lot,

[#4]

yeah thanks.. append works.. \\n (double backslash) doesnt.. I was doing this while writing count to file.. it now works.. The count is: ${executesql.row.count:append('\n')}

[#5]

When entering text values into NiFi you should be able to hit "Shift-Enter" and it will give you true new lines. See attached screenshot

[#6]

Joe - What processor is being illustrated?

[#7]

@Obaid Salikeen

Try using \\n (double backslash) or using 'Shift + enter" in the expression language editor box to create new lines in your replacement string as shown by Joe Witt above. Thanks,

Matt