Class: Dash::Cli::Healthcheck::ProgressReporter

Inherits:
Object
  • Object
show all
Defined in:
lib/dash/cli/healthcheck/progress_reporter.rb

Overview

Turns the server-side readiness wait's progress lines back into the beacon the client-side poll used to print. It is an SSHKit interaction handler, so it sees the wait's stderr as it streams — the operator gets the same once-a-second feedback they got when the laptop was the thing doing the polling, for one round trip instead of one per attempt. The cadence is fixed at a second because the host loop's is.

The stream is line-oriented but arrives in chunks (the SSH backend splits on packet boundaries, not newlines), so data is buffered and only whole lines are reported. Only stderr is buffered: the wait's stdout carries the final status, and stdout and stderr are separate SSH streams whose chunks can interleave — folding both into one buffer would let the status land in the middle of a half-arrived progress line and corrupt them both. Anything on stderr that is not a progress line (docker's own complaints) is ignored.

Constant Summary collapse

LINE = 
/\A#{Regexp.escape(Dash::Commands::Base::READINESS_PROGRESS_PREFIX)} (?<elapsed>\d+) (?<left>\d+)(?: |\z)/

Instance Method Summary collapse

Constructor Details

#initialize ⇒ ProgressReporter

Returns a new instance of ProgressReporter.



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# File 'lib/dash/cli/healthcheck/progress_reporter.rb', line 16

def initialize
  @buffer = +""
  @mutex = Mutex.new
end

Instance Method Details

#on_data(_command, stream_name, data, _channel = nil) ⇒ Object

SSHKit's interaction-handler contract.



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# File 'lib/dash/cli/healthcheck/progress_reporter.rb', line 22

def on_data(_command, stream_name, data, _channel = nil)
  return unless stream_name == :stderr

  @mutex.synchronize do
    @buffer << data.to_s
    while (newline = @buffer.index("\n"))
      report @buffer.slice!(0..newline).chomp
    end
  end
end