trjhtr

Following up from my previous question

Streaming my UPS metrics for graphical viewing in bash

#!/usr/bin/env bash

[ -v METRICS_CHECK ] && set -x

API_URL="https://api.thingspeak.com/update"
UPS_PROPS=("LINEV" "LOADPCT" "TIMELEFT")
API_PARAMS=("api_key==XXXXXXXXXXXXXX")

for index in "$!UPS_PROPS[@]"
do
 value=$(/sbin/apcaccess -up "$UPS_PROPS[$index]")
 field=$((index + 1))
 if [ "$field" -eq 2 ]
 then
 # bc required for floating point arithmetic
 value=$(echo "$value * 6" | bc) # 600 Watt * load percent
 fi
 PARAM=$(printf "field%d==%s" "$field" "$value")
 API_PARAMS+=("$PARAM")
done

/usr/local/bin/http "$API_URL" $API_PARAMS[@]

Updates:

• Collects data for different metrics supported by apcaccess
  


• Use a variable check for enabling debug mode


• Split parameters sent to API URL into a different array


• Move away from curl to use httpie
  


• Custom computation for certain attributes

The shellcheck passes everything except the unquoted $API_PARAMS[@] in the last line. I am not sure that httpie would work if I quote that and pass it as a single argument.

Charts for viewing pleasure (last 600 minutes data from the time post was created):

1. 
   

   Input line voltage

   
   
   

   

   
   


2. 
   

   Load (in wattage) on the UPS

   
   
   

   

   
   


3. 
   

   Battery time left for the UPS

   
   
   

   

   
   

Click the images to get live charts.

Quoting - you need double-quotes on the last line: it should be "$API_PARAMS[@]" (remember that the [@] makes the shell expand it into multiple words, so it won't be seen by your http program as just one).

Instead of if [ "$field" -eq 2 ], it's clearer to compare the field name. That will help if you change the properties list in future. It may help to create a variable:

propname="$UPS_PROPS[$index]"
value=$(/sbin/apcaccess -up "$propname")
if [ "$propname" = LOADPCT ]

We can supply standard input from a string without needing an echo process, by using <<< redirection:

 # bc required for floating point arithmetic
 value=$(<<<"$value * 6" bc) # 600 Watt * load percent

We can make the array 1-based, and avoid the need to have $field different from $index:

UPS_PROPS=([1]="LINEV" "LOADPCT" "TIMELEFT")