tail/pipe kubectl logs to a slack channel with slackcat

kubectl-logs-to-slack.sh

#!/bin/sh
set -e

ARCH=amd64
KUBECTL_VERSION=1.27.2
TETRAGON_VERSION=0.9.0
SLACKCAT_VERSION=1.7.3
SLACK_CHANNEL=test

apk -q add curl grep sed coreutils

curl -sLO https://dl.k8s.io/release/v$${KUBECTL_VERSION}/bin/linux/$${ARCH}/kubectl
chmod +x ./kubectl

curl -sLo slackcat https://github.com/bcicen/slackcat/releases/download/$${SLACKCAT_VERSION}/slackcat-$${SLACKCAT_VERSION}-linux-$${ARCH}
chmod +x ./slackcat

echo "$SLACK_TOKEN" > ~/.slackcat

LOOP_MINS=1
LAST_SCAN=$(date --iso-8601=seconds --date "-$LOOP_MINS min")
MAX_LINES_PER_LOOP=100
MAX_LOG_REQUESTS=200

echo "starting tetragon log to slack..."

while true; do
  WAIT_UNTIL=$(date --iso-8601=seconds --date="$LAST_SCAN +$LOOP_MINS min")

  if [ "$(date '+%s')" -gt "$(date --date "$WAIT_UNTIL" '+%s')" ]; then
    echo "requesting logs since $WAIT_UNTIL..."

    START_SCAN=$(date --iso-8601=seconds)
    ./kubectl logs --since-time "$LAST_SCAN" \
      --namespace ${var.namespace} \
      --selector app.kubernetes.io/name=tetragon \
      --container export-stdout \
      --max-log-requests $MAX_LOG_REQUESTS \
      --tail $MAX_LINES_PER_LOOP | \
      ./slackcat --stream --channel $SLACK_CHANNEL

    LAST_SCAN="$START_SCAN"
  fi

  sleep 5
done

This issue with kubelet forced me to write this as a loop. kubernetes/kubernetes#115701

if you are going to put other modifications in the chain make sure they are set to not buffer very much.

      sed --unbuffered -r 's|^(\w+) (.*)$|*\1* `\2`|' | \
      grep --line-buffered -v -E "(stuff|we|dont|want|to|see)" | \

these scopes are required for the slackcat bot app, their auto-setup is broken atm.

["chat:write", "im:read", "mpim:read", "channels:read", "groups:read", "files:write", "users:read"]