# Reproducible Builds

## Building with Docker

To create a Loop release with binaries that are identical to an official
release, run the following command (available since release `v0.31.3-beta`):

```bash
make docker-release tag=<tag-of-release>
```

This command will create a directory named `loop-<tag-of-release>` containing
the source archive, vendored dependencies, and the built binaries packaged in
`.tar.gz` or `.zip` format. It also creates a manifest file with `SHA-256`
checksums for all release files.

For example:

```bash
make docker-release tag=v0.31.3-beta
```

This will create the release artifacts in the `loop-v0.31.3-beta` directory.

If you want to build from an untagged commit, first check it out, then use the
output of `git describe --abbrev=10` as the tag:

```bash
git describe --abbrev=10
# v0.31.2-beta-135-g35d0fa26ac

make docker-release tag=v0.31.2-beta-135-g35d0fa26ac
```

You can filter the target platforms to speed up the build process. For example,
to build only for `linux-amd64`:

```bash
make docker-release buildsys=linux-amd64 tag=v0.31.3-beta
```

Or for multiple platforms:

```bash
make docker-release buildsys='linux-amd64 windows-amd64' tag=v0.31.3-beta
```

Note: inside Docker the current directory is mapped as `/repo` and it might
mention `/repo` as parts of file paths.

## Building on the Host

You can also build a release on your host system without Docker. You will need
to install the Go version specified in the `go.mod` file, as well as a few
other tools:

```bash
sudo apt-get install build-essential git make zip perl gpg
```

You can [download](https://go.dev/dl/) and unpack Go somewhere and set variable
`GO_CMD=/path/to/go` (path to Go binary of the needed version).

If you already have another Go version, you can install the Go version needed
for a release using the following commands:

```bash
$ go version
go version go1.25.0 linux/amd64
$ go install golang.org/dl/go1.24.9@latest
$ go1.24.9 download
Unpacking /home/user/sdk/go1.24.9/go1.24.9.linux-amd64.tar.gz ...
Success. You may now run 'go1.24.9'
$ go1.24.9 version
go version go1.24.9 linux/amd64

$ GO_CMD=/home/user/go/bin/go1.24.9 ./release.sh v0.31.5
```

On MacOS, you will need to install GNU tar and GNU gzip, which can be done with
`brew`:

```bash
brew install gnu-tar gzip
```

Add GPG key of Alex Bosworth to verify release tag signature:
```bash
gpg --keyserver keys.openpgp.org --recv-keys DE23E73BFA8A0AD5587D2FCDE80D2F3F311FD87E
```

Then, run the `release.sh` script directly:

```bash
./release.sh <tag-of-release>
```

To filter the target platforms, pass them as a space-separated list in the
`LOOPBUILDSYS` environment variable:

```bash
LOOPBUILDSYS='linux-amd64 windows-amd64' ./release.sh v0.31.3-beta
```

This will produce the same artifacts in a `loop-<tag-of-release>` directory as
the `make docker-release` command. The latter simply runs the `release.sh`
script inside a Docker container.
