Are Crlf Lines Ok in a Rails Project Deployed on Linux

Are CRLF lines ok in a Rails project deployed on Linux?

If it is ok for you to rewrite your repository's history (see problems with rewriting history) you could use git filter-branch to convert CRLF to LF:

git filter-branch --tree-filter 'find . -path './.git' -prune -o -type f -exec dos2unix \{} \;' HEAD

Note that if you have binary files in your repository you will have to refine the find command to exclude them.

Line endings messed up in Git - how to track changes from another branch after a huge line ending fix?

I finally managed to solve it.

The answer is:

git filter-branch --tree-filter '~/Scripts/fix-line-endings.sh' -- --all

fix-line-endings.sh contains:

#!/bin/sh
find . -type f -a \( -name '*.tpl' -o -name '*.php' -o -name '*.js' -o -name '*.css' -o -name '*.sh' -o -name '*.txt' -iname '*.html' \) | xargs fromdos

After all line endings were fixed in all trees in all commits, I did an interactive rebase and removed all commits that were fixing line endings.

Now my repo is clean and fresh, ready to be pushed :)

Note to visitors: do not do this if your repo has been pushed / cloned because it will mess things up badly!

Git: Removing carriage returns from source-controlled files

The approach you’ll have to use depends on how public your repository is.

If you don’t mind or care about changing all SHAs because you’re more or less the only one using it but want to have this issue sorted out for all times, you can run a git filter-branch and apply dos2unix to all files in each commit. (If you’re sharing the repository, everyone else needs more or less to completely renew it, so this is potentially dangerous.)

So the better option and also an easier way would be to change it only in the current heads. This means that your past commits still have \r\n endings but unless you’re doing much cherry-picking from the past this should not be a problem. The diff tools might complain a bit more often, of course, but normally you’ll only diff with commits in the vicinity, so this issue resolves itself as the commits accumulate.

And UNIX line endings are standard, you’re correct about that. Best approach is to setup your editor to only write these endings even on windows. Otherwise, there is also a autocrlf setting which you can use.

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Addition to the history rewriting part:

Last time I did the same, I used the following command to change all files to unix endings.

#!/bin/bash
all2dos() { find * -exec dos2unix {} \; }
export -f all2dos
git filter-branch -f --tree-filter 'all2dos' --tag-name-filter cat --prune-empty -- --all

Wait until file is unlocked in .NET

This was the answer I gave on a related question:

    /// <summary>
    /// Blocks until the file is not locked any more.
    /// </summary>
    /// <param name="fullPath"></param>
    bool WaitForFile(string fullPath)
    {
        int numTries = 0;
        while (true)
        {
            ++numTries;
            try
            {
                // Attempt to open the file exclusively.
                using (FileStream fs = new FileStream(fullPath,
                    FileMode.Open, FileAccess.ReadWrite, 
                    FileShare.None, 100))
                {
                    fs.ReadByte();

                    // If we got this far the file is ready
                    break;
                }
            }
            catch (Exception ex)
            {
                Log.LogWarning(
                   "WaitForFile {0} failed to get an exclusive lock: {1}", 
                    fullPath, ex.ToString());

                if (numTries > 10)
                {
                    Log.LogWarning(
                        "WaitForFile {0} giving up after 10 tries", 
                        fullPath);
                    return false;
                }

                // Wait for the lock to be released
                System.Threading.Thread.Sleep(500);
            }
        }

        Log.LogTrace("WaitForFile {0} returning true after {1} tries",
            fullPath, numTries);
        return true;
    }

How to run a cron job inside a docker container?

You can copy your crontab into an image, in order for the container launched from said image to run the job.

See "Run a cron job with Docker" from Julien Boulay in his Ekito/docker-cron:

Let’s create a new file called "hello-cron" to describe our job.

# must be ended with a new line "LF" (Unix) and not "CRLF" (Windows)
* * * * * echo "Hello world" >> /var/log/cron.log 2>&1
# An empty line is required at the end of this file for a valid cron file.

If you are wondering what is 2>&1, Ayman Hourieh explains.

The following Dockerfile describes all the steps to build your image

FROM ubuntu:latest
MAINTAINER docker@ekito.fr

RUN apt-get update && apt-get -y install cron

# Copy hello-cron file to the cron.d directory
COPY hello-cron /etc/cron.d/hello-cron
 
# Give execution rights on the cron job
RUN chmod 0644 /etc/cron.d/hello-cron

# Apply cron job
RUN crontab /etc/cron.d/hello-cron
 
# Create the log file to be able to run tail
RUN touch /var/log/cron.log
 
# Run the command on container startup
CMD cron && tail -f /var/log/cron.log

(see Gaafar's comment and How do I make apt-get install less noisy?:

apt-get -y install -qq --force-yes cron can work too)

As noted by Nathan Lloyd in the comments:

Quick note about a gotcha:

If you're adding a script file and telling cron to run it, remember to

RUN chmod 0744 /the_script

Cron fails silently if you forget.

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OR, make sure your job itself redirect directly to stdout/stderr instead of a log file, as described in hugoShaka's answer:

 * * * * * root echo hello > /proc/1/fd/1 2>/proc/1/fd/2

Replace the last Dockerfile line with

CMD ["cron", "-f"]

See also (about cron -f, which is to say cron "foreground") "docker ubuntu cron -f is not working"

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Build and run it:

sudo docker build --rm -t ekito/cron-example .
sudo docker run -t -i ekito/cron-example

Be patient, wait for 2 minutes and your commandline should display:

Hello world
Hello world

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Eric adds in the comments:

Do note that tail may not display the correct file if it is created during image build.

If that is the case, you need to create or touch the file during container runtime in order for tail to pick up the correct file.

See "Output of tail -f at the end of a docker CMD is not showing".

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See more in "Running Cron in Docker" (Apr. 2021) from Jason Kulatunga, as he commented below

See Jason's image AnalogJ/docker-cron based on:

• Dockerfile installing cronie/crond, depending on distribution.

• an entrypoint initializing /etc/environment and then calling

  cron -f -l 2
  

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