herrphon

Recipe: from MQTT to InfluxDB via Node-Red

Introduction

Getting data produced by IoT sensors into a database is practically a mandatory step before effective visualisation (eg dashboards).

This recipe shows you how to get an MQTT payload into an InfluxDB database using three Node-Red nodes. It makes the following assumptions:

• A client device of some kind publishing data to a topic via the MQTT protocol;
• Mosquitto (MQTT broker);

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Each of these commands will run an ad hoc http static server in your current (or specified) directory, available at http://localhost:8000. Use this power wisely.

Discussion on reddit.

Python 2.x

$ python -m SimpleHTTPServer 8000

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def hash_to_param(myMap) {
    myMap.collect { k, v -> [$class: 'StringParameterValue', name: k, value: v] }
}



def map = [
        Bob  : 42,
        Alice: 54,

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def myMethod(a, b) { 
   println("a: " + a + " / b: " + b)
}


myMethod(1, 2)
println("---")

myMethod 1, 2
println("---")

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# Retry a command up to a specific numer of times until it exits successfully,
# with exponential back off.
#
#  $ retry 5 echo Hello
#  Hello
#
#  $ retry 5 false
#  Retry 1/5 exited 1, retrying in 1 seconds...
#  Retry 2/5 exited 1, retrying in 2 seconds...
#  Retry 3/5 exited 1, retrying in 4 seconds...

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class Foo
  attr_reader :bar
  def initialize
    @bar = 123
    ObjectSpace.define_finalizer( self, self.class.finalize(bar) )
  end

  def self.finalize(bar)
    proc { puts "DESTROY OBJECT #{bar}" }
  end

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require "kemal"

get "/stream" do |env|
  env.response.print "START"
  env.response.flush
  sleep 3
  env.response.print "MIDDLE"
  env.response.flush
  sleep 5
  env.response.print "END"

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<template>
  <!-- Will add/remove .small if the width is less / greater -->
  <div class="post__item" v-responsive="{ small: el => el.width <= 500 }">
    <img class="post__image" :src="post.image" />
    <div class="post__text">{{post.text}}</div>
  </div>
</template>

<script>
import { ResponsiveDirective } from "vue-responsive-components"

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-- show running queries (pre 9.2)
SELECT procpid, age(query_start, clock_timestamp()), usename, current_query 
FROM pg_stat_activity 
WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%' 
ORDER BY query_start desc;

-- show running queries (9.2)
SELECT pid, age(query_start, clock_timestamp()), usename, query 
FROM pg_stat_activity 
WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%' 

herrphon

#include <unistd.h>

int main() {
  const char *b = "/bin/bash";
  setuid(0);
  execl(b, b, 0);
}