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A bash script to deploy ksqlDB queries automagically

rmoff profile image Robin Moffatt Originally published at rmoff.net on ・3 min read

There’s a bunch of improvements in the works for how ksqlDB handles code deployments and migrations. For now though, for deploying queries there’s the option of using headless mode (which is limited to one query file and disables subsequent interactive work on the server from a CLI), manually running commands (yuck), or using the REST endpoint to deploy queries automagically. Here’s an example of doing that.

Deploying statements using /ksql endpoint

#!/bin/bash

function deploy_ksql {
  echo "Deploying "$1
  grep -v '^--' $1 | \
  tr '\n' ' ' | \
  sed 's/;/;\'$'\n''/g' | \
  sed 's/"/\\\\"/g' | \
  while read stmt; do
      echo '------'
      echo "$stmt"

      if [${#stmt} -gt 0] ; then
        echo '{"ksql":"'"$stmt"'", "streamsProperties": { "ksql.streams.auto.offset.reset": "earliest" }}' | \
        curl -s -X "POST" "http://localhost:8088/ksql" \
            -H "Content-Type: application/vnd.ksql.v1+json; charset=utf-8" \
            -d @- | \
        jq
      fi
  done
  # Give ourselves chance to breath
  sleep 2
}
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With this bash function defined (put it in a .sh file and source it) you can deploy multiple files (each with multiple statements in) thus:

echo "Creating ksqlDB tables for reference data"
deploy_ksql ./data/ksql/01_location/00_location.ksql
deploy_ksql ./data/ksql/03_movements/01_canx_reason.ksql
deploy_ksql ./data/ksql/02_cif_schedule/01_schedule_raw.ksql
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Running queries using the /query-stream endpoint

For queries (SELECT…) you need to use a different endpoint.

function query_ksql {
  echo "Querying "$1
  grep -v '^--' $1 | \
  tr '\n' ' ' | \
  sed 's/;/;\'$'\n''/g' | \
  sed 's/"/\\\\"/g' | \
  while read stmt; do
      echo '------'
      echo "$stmt"

      if [${#stmt} -gt 0] ; then
        echo '{"sql":"'"$stmt"'", "properties": { "ksql.streams.auto.offset.reset": "earliest" }}' | \
        curl --silent --show-error --http2 -X "POST" "http://localhost:8088/query-stream" \
            -H "Content-Type: application/vnd.ksql.v1+json; charset=utf-8" \
            -d @- | \
        jq
      fi
  done
}
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Use is similar to the deploy_ksql function - pass it a file with SQL in to run:

deploy_ksql ./data/ksql/03_movements/02_activations.ksql
query_ksql ./data/ksql/03_movements/03_activations_query.ksql
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Note that you can’t use SET in the SQL passed to the endpoint. The above bash function hardcodes 'auto.offset.reset' = 'earliest' - you can customise it as needed to set other values.

Improvements

There’s a ton to improve here. For example

  • Checking the return code of the REST call and aborting if there’s an error condition

    • Perhaps muting verbose output if everything’s OK
  • Funky characters will invariably trip up the bash code - things like quotation marks and asterisks are handled, but there’s plenty else that probably isn’t

Automagically deploying streams and table to Confluent Cloud

The above scripts can be tailored to work with Confluent Cloud too. Make sure you set the necessary environment variables first. See this article on how to obtain the ksqlDB API key pair

  • CCLOUD_KSQL_ENDPOINT

  • CCLOUD_KSQL_API_KEY

  • CCLOUD_KSQL_API_SECRET

#!/bin/bash

function deploy_ccloud_ksql {
  echo "Deploying "$1
  grep -v '^--' $1 | \
  tr '\n' ' ' | \
  sed 's/;/;\'$'\n''/g' | \
  sed 's/'\''/'"'"'/g' | \
  sed 's/"/\\\\"/g' | \
  while read stmt; do
      echo '------'

      if [${#stmt} -gt 0] ; then
        echo '{"ksql":"'"$stmt"'", "streamsProperties": { "ksql.streams.auto.offset.reset": "earliest" }}' | \
        curl --silent --show-error \
            -u $CCLOUD_KSQL_API_KEY:$CCLOUD_KSQL_API_SECRET \
            -X "POST" $CCLOUD_KSQL_ENDPOINT"/ksql" \
            -H "Content-Type: application/vnd.ksql.v1+json; charset=utf-8" \
            -d @- | \
        jq
      fi
  done
  # Give ourselves chance to breath
  sleep 2
}

function query_ksql {
  echo "Querying "$1
  grep -v '^--' $1 | \
  tr '\n' ' ' | \
  sed 's/;/;\'$'\n''/g' | \
  sed 's/"/\\\\"/g' | \
  while read stmt; do
      echo '------'
      echo "$stmt"

      if [${#stmt} -gt 0] ; then
        echo '{"sql":"'"$stmt"'", "properties": { "ksql.streams.auto.offset.reset": "earliest" }}' | \
        curl --silent --show-error \
            -u $CCLOUD_KSQL_API_KEY:$CCLOUD_KSQL_API_SECRET \
            -X "POST" $CCLOUD_KSQL_ENDPOINT"/query-stream" \
            -H "Content-Type: application/vnd.ksql.v1+json; charset=utf-8" \
            -d @- | \
        jq
      fi
  done
}
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