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“import cycle not allowed”
  • code samples,
  • gotchas areas, and
  • theories

code — how it works

The…


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what is a “mapping” and why is there a pollution?

Like any datastore solutions, there must be a schema equivalent setting to illustrate how a data field would be treated (e.g. stored and processed / analysed); this setting is known as “Mapping” under Elasticsearch.


  • code samples,
  • gotchas areas, and
  • theories

Code — how it works

The source code…


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setting a value based on a source field

Take an example, we have a field named “categoryValue”. If this value equals to “plant” then the field “categoryCode”’s value would be set to “A”. The following is the logic matrix:

  • categoryValue = “plant”, categoryCode = “A”
  • categoryValue = “animal”, categoryCode = “B”


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why need monitoring and why need metricbeat???

A commonly asked question but seldom got answered. First of all, no matter if we are deploying docker containers or the good old-fashion metal boxes (i.e. physical servers), it is crucial to monitor their health. The major concern is when we have several servers running in the…



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the filebeat way

First of all, we need to prepare a dataset. For simplicity, it would be like the following:


devops terminal

a java / golang / flutter developer, a big data scientist, a father :)

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