Here is a more involved example of downloading a release and then extracting the binary from a .pkg file: https://gist.github.com/J-Swift/364a8b158bf0b603f6e784e454ca...
Here is a more simplified example: https://gist.github.com/mitchellh/c47e3333bb78f57836ba2aa806...
EDIT: to get the sha, unfortunately you have to perform some esoteric command line incantations: https://github.com/NixOS/nix/issues/1880#issuecomment-366615... and https://gist.github.com/boxofrox/d8a3080fbb03f84b7d7a31e102b...
If you don't care about Nixpkgs conventions ("build phases", etc.) then you can use `runCommand` to run arbitrary bash code. It's a function which takes three arguments: a name for the output, a key/value mapping for the environment variables (plus a few some special names), and a string of bash code (usually written between ''two single quotes'').
with import <nixpkgs> {};
runCommand
"my-favourite-program" # A name for the output
{
# A key/value mapping of env vars
myVar = "myValue";
# The 'buildInputs' name is special: for each element 'x', the directory '${x}/bin'
# will be appended to the PATH env var
buildInputs = [ jq gcc ];
}
''
# This is a multi-line string containing arbitrary bash code.
# The output path will be provided via the env var $out so we
# just need to create a file or folder with that path
mkdir -p "$out/bin"
echo "$myVar" > "$out/bin/my-executable"
chmod +x "$out/bin/my-executable"
''
with import <nixpkgs> {};
runCommand "foo"
{
release = fetchurl {
url = "http://example.com/foo/foo-1.0.zip";
hash = "sha256-iqZDwWkQA9XMTICEMCt5xDlmfmiIwzpeE3HJLbgbDXs=";
};
buildInputs = [ unzip ];
}
''
unzip "$release"
mkdir -p "$out/bin"
mv foo-1.0/binary "$out/bin/foo"
''The good news is once you learn how, it's basically trivial with crate2nix[0], which can autogenerate nix derivations from rust crates