* s3thorp

Synchronisation of files with S3 using the hash of the file contents.

Originally based on Alex Kudlick's [[https://github.com/akud/aws-s3-sync-by-hash][aws-s3-sync-by-hash]].

The normal ~aws s3 sync ...~ command only uses the time stamp of files
to decide what files need to be copied. This utility looks at the md5
hash of the file contents.

* Usage

  #+begin_example
    s3thorp
    Usage: s3thorp [options]

      -s, --source <value>             Source directory to sync to S3
      -b, --bucket <value>             S3 bucket name
      -p, --prefix <value>             Prefix within the S3 Bucket
      -x, --exclude <value>[,<values>] Exclude matching paths
      -v, --verbose <value>            Verbosity level (1-5)
  #+end_example

* Behaviour

When considering a local file, the following table governs what should happen:

|---+------------+------------+------------------+--------------------+---------------------|
| # | local file | remote key | hash of same key | hash of other keys | action              |
|---+------------+------------+------------------+--------------------+---------------------|
| 1 | exists     | exists     | matches          | -                  | do nothing          |
| 2 | exists     | is missing | -                | matches            | copy from other key |
| 3 | exists     | is missing | -                | no matches         | upload              |
| 4 | exists     | exists     | no match         | matches            | copy from other key |
| 5 | exists     | exists     | no match         | no matches         | upload              |
| 6 | is missing | exists     | -                | -                  | delete              |
|---+------------+------------+------------------+--------------------+---------------------|

* Creating Native Images

  - Download and install GraalVM
    - https://github.com/oracle/graal/releases
  - Install ~native-image~ using the graal updater
    #+begin_example bash
      gu install native-image
    #+end_example
  - Create native image
    #+begin_example bash
      native-image -cp `sbt 'export runtime:fullClasspath'|tail -n 1` \
                   -H:Name=s3thorp \
                   -H:Class=net.kemitix.s3thorp.Main \
                   --allow-incomplete-classpath \
                   --force-fallback
    #+end_example
  - Resulting file requires a JDK for execution