👻 Spook in the Shell 👻 (Spit-sh)
Spook in the Shell (Spit or Spit-sh) is a
language/compiler that outputs shell scripts. It compiles a strongly
typed Perl 6 like language called "Spook" into /bin/sh
compatible
scripts. It's main purpose is devops/infrastructure related
tasks. Current features include:
- Compile time type checking
- Basic libraries/modules
- Test module for outputting TAP
- Useful builtin classes and functions
- Running and testing scripts in Docker
- Logging to standard output
Everything about the language and compiler is still experimental. I am
thinking about pivoting a bit into compiling golang to create
standalone binaries instead of shell scripts. 🤔
Example
To get an idea of what Spit is consider the following basic program:
.install unless Pkg<nc>; # install nc unless it's already there
ok Cmd<nc>,"nc command exists now"; # test the nc command is there
You can compile this for CentOS from the command line like:
spit eval --os=centos '.install unless Pkg<nc>; ok Cmd<nc>,"nc command exists now"'
Which ouputs the following shell at the time of writing:
BEGIN(){
e(){ printf %s "$1"; }
exec 4>/dev/null
installed(){ yum list installed "$1" >&4 2>&4; }
install(){ yum install -y $1 >&4 2>&4; }
exists(){ command -v "$1" >&4; }
exec 3>&1
say(){ printf '%s\n' "$1" >&3; }
note(){ printf '%s\n' "$1" >&2; }
die(){ note "$1" && kill "-TERM" $$ >&4; }
ok(){ test "$1" && say "✔ - $2" || die "✘ - $2"; }
}
MAIN(){
if ! installed nc; then
install nc
fi
ok "$(exists nc && e 1)" 'nc command exists now'
}
BEGIN && MAIN
If you have docker installed you can test this with:
spit eval --in-docker=centos '.install unless Pkg<nc>; ok Cmd<nc>,"nc command exists now"'
✔ - nc command exists now
Unfortunately on Debian the package is named 'netcat'. Let's deal with that:
# install-nc.sp
constant Pkg $nc = on {
Debian { 'netcat' }
Any { 'nc' } # the default
};
.install unless $nc;
ok Cmd<nc>,"nc command exists now";
And now it should work on both the RHEL and Debian families of
Linux distributions.
spit compile install-nc.sp --in-docker=debian:latest
✔ - nc command exists now
Install
Spit is written in Perl 6 and
requires rakudo and something to
install Perl 6 ecosystem modules with
like zef.
zef install Spit
and run
spit eval 'say "hello world"'
To check it's working.
Documentation
The documentation is pretty useless at the moment because the tooling has
fallen far behind the language. What exists is under: doc/.
Project Layout
- The Perl 6 Spit compiler module is in
lib
- The actual Spit source code is under
resources/src
- The core spit modules are under
resouces/core-lib
- The spec tests are in
spec
.