Always fetch latest events in tail

[mkotsalainen]

Is your feature request related to a problem? Please describe.

I would like to always get the latest events from a certain log stream - like AWS CloudWatch console does it. If nothing recent has been published to a certain log - I would still want the latest n items to show up.

Describe the solution you'd like

If I tail a log with cw and there hasn't been a lot of traffic in that stream recently nothing will show. I could give it a --start parameter but I don't know what that start parameter should be. Some of logs are really high volume and some are almost empty.

By using aws logs get-log-events I get a timestamp of the latest log item, that could be used a indication of the start param.

Describe alternatives you've considered

I've been thinking of wrapping cw in a shell script that does this but I think this functionality would be better implemented in the util itself.

Additional context

I have a nice fuzzy finder logs setup that is almost complete - I just need this feature to ditch the AWS logs console altogether
:

declare -A log_streams

function refresh_log_streams_list {
  log_streams=()
}

function logs {
  # Mashup of https://github.com/lucagrulla/cw and https://github.com/junegunn/fzf
  # Also uses unbuffer avaiable on mac via brew install expect
  # Allows you to access logs quickly
  env=$1
  query=$2
  if [[ -z ${log_streams["$env"]} ]] ; then
    echo "refreshing $env log_stream_list"
    log_streams["$env"]=$(cw ls streams pilot-$env)
  fi
  echo "$log_streams["$env"]" | fzf --ansi --preview-window "right,80%" --info inline --border -q "$query" --preview-window follow --preview "unbuffer cw tail -tf pilot-$env:{}" | xargs -I '{}' cw tail -tf pilot-$env:{}
}