CODEWITHSUNDEEP
rubyprogress-barstdout
Israel
Israel

Reputation: 3402

ruby-progressbar and stdout

Suppose I have a method which computes hard problems (maybe a depth-first search in a huge graph), we can call this method dfs(graph). This method also output to stdout each result reached, using puts result.

def dfs(graph)
  while true
    # lots of computation

    result = something_reached
    puts result
  end
end

I want to display a progressbar in shell to show that computation is running, so I add an instance like this:

pbar = ProgressBar.create(title: "Computing", starting_at: 1, total: nil)

and progressbar status must be updated (pbar.increment) as computation is running.

In a shell, I execute my program like this:

ruby dfs.rb > dfs_results.txt

Issues:

Question:

How should I be implemented to flush computation resulta to dfs_results.txt file and show a progress-bar to keep a executing progress for user?

Upvotes: 2

Views: 761

Answers (1)

spickermann
spickermann

Reputation: 106882

Just open a file to log into:

log = File.open('dfs_results.txt', 'w') 

# write into log file
log.write(result)

And your progressbar still writes to stdout. When you open a second screen you can follow the output with:

tails -f dfs_results.txt

Update: Or you can use stdout for the progressbar and stderr for the output of the script. Instead of puts result write:

$stderr.puts results

and start the script with:

ruby dfs.rb 2> dfs_results.txt

I still think the first version is better because results are not errors...

Upvotes: 1

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