reto - The release tool

Installing

Install by running go get -u github.com/ExploratoryEngineering/reto/cmd/reto or download the binaries from the release page.

About

This is a tool to manage releases and change logs for releases. Strictly speaking is't just a zip file generator with versioning.

Some of the the goals for the tool are:

• Work within the source tree without imposing any weird build steps.
• Be non-intrusive.
• Work with (almost) any source code.
• Automate release notes/change logs for the different version.
• Make releases that are easily mapped to source code revisions.
• Semantic versioning. It's not necessarily something that end users care about (they are mostly focused on features and if it works or not)
• Support software on multiple platforms and architectures.
• Handle sets of binaries and resources (such as documentation, upgrade scripts and so on)
• Possible to automate on build servers and in makefiles.

We're assuming the following:

• Git is the SCM of choice.
• Semantic versioning (or a scheme with major-minor-patch version numbering) is used.
• There's a changelog accompanying each release. The complete change log is included with each release, the newest is kept at the top.
• You can set the version numbers during the build.
• When you do a release everything is commited to Git.
• There's no roll back semantics. If something goes wrong when you generate a release you can use Git to check out the previous version. The contents of the release directory are kept under source control and in sync with the rest of the source. If something breaks (or a release goes terribly pear-shaped) you can roll back the changes via Git.
• Changelogs are written in markdown formats.

These are the things we don't care about:

• Nothing is built by the tool except the zip files.
• The source code. Or if there is any source code.
• The build process. You build the sofware the way you want to.
• The tool is a tool not a life style choice.
• How your commits look like. You can do one giant commit for each release or you can to thousands.
• What the change log for each version says. The tool does not write a change log for you. You can automate this by looking at the commits but that's not somthing the tool cares about. As long as the change log is free of "TODO" (it's a basic safeguard)

What it does

The tool keeps track of the current version. The current version is always incremented, either by patch number, minor or major version. You can edit the version file manually to step backwards.

The changelog in release/changelog.md documents the new features, bugs and other information you want to include with the current release.

When a a release is built a new directory is created (release/n.n.n where n.n.n is the current version) and the current changelog (in release/changelog.md) is copied to the release directory. The changelog from all releases are merged into one big changelog.md and the built binaries and associated files are copied into zip archives under release/archives/n.n.n, one archive for each target set up in the configuration file. If the configuration includes additionla files these are added to the archive as well.

The SHA256 hash for each file included in the archives are computed and written to the file release/archives/n.n.n/sha256sum_[name]_n.n.n.txt

Once the release is completed the template changelog is copied from release/templates/changelog_template.md to release/changelog.md, ready for the next release.

Configuration file

The configuration file is a JSON file in release/config.json. It looks like the following (the example is for the tool itself):

{
    "sourceRoot": ".",
    "name": "reto",
    "committerName": "Reto release tool",
    "committerEmail": "[email protected]",
    "targets": [
        "darwin-amd64", "linux-amd64", "windows-amd64", "linux-arm"
    ],
    "templates": [
        { "name": "changelog.md", "action": "concatenate" },
        { "name": "verify.txt",   "action": "include" },
        { "name": "releases.txt", "action": "concatenate" }
    ]
    "files": [
        { "id": "tool", "name": "bin/reto.darwin-amd64","target": "darwin-amd64" },
        { "id": "tool", "name": "bin/reto.linux-amd64", "target": "linux-amd64" },
        { "id": "tool", "name": "bin/reto.linux-arm", "target": "linux-arm" },
        { "id": "tool", "name": "bin/reto.windows-amd64", "target": "windows-amd64" },
        { "id": "readme", "name": "README.md", "target": "-" }
    ]
}

• name is the name of the product.
• committerName and committerEmail is the name and email used when tagging git releases.
• sourceRoot points to the source code root. Usually you'd want the release files to reside next to the tool itself but if you want to put the release files elsewhere you can set the path to point to the root of the source code.
• targets is a list of target strings that you plan to release. This can be a single string (if you have a single target) or multiple strings depending on what (and how) you build your released binaries. The strings can be anything as long as they are unique.
• templates are templates for files included in the release archives. They can either be included as is (with action set to "include") or they can be aggregated logs (like a changelog) that are aggregates of this and all previous releases.
• The files section contains a list of files. Each file has an id property that groups the differnt files into one. If a file is common for all targets use the target '-', typically text files, PDFs or images. If you list three different targets in the targets property you must have the same three targets for each id. The name field is the file name of the file to include.

Fancy naming of commit hashes

Commit hashes gets user-friendly names. The first three bytes are translated into an adjective-name string that identifies the commit. This is enough to get relatively unique version names for different releases.

Names can get quite interesting and someone might be offended if they put their mind to it but it's a nice option to have if you have frequent releases and use the semantic version for internal features as well as external features.

(Your end users might not care one iota about the new backwards incompatible flag `--upsert-before-commit-with-logstash-logging' but you still have a version that the end users can relate to)

Commit names are withering-gustie well-spoken-amin timid-chesley, effervescent-laurie and appropriate-yulissa.

Setting versions in Go builds

You can use the ldflags parameter to set variables in Go packages. If you look at the tool itself the file pkg/version/version.go contains the variables Number, Name, CommitHash and BuildTime that has suitable defaults.

If you build the executable with the ldflags parameter set like this:

go build -ldflags "-X github.com/ExploratoryEngineering/reto/pkg/version.Number=1.0.0 -X github.com/ExploratoryEngineering/reto/pkg/version.Name=psychological-karson -X github.com/ExploratoryEngineering/reto/pkg/version.CommitHash=e02bc6cd8ab3edd3d6e8874d1e97c08ef6c5db49 -X github.com/ExploratoryEngineering/reto/pkg/version.BuildTime=2020-02-01T22:35"

The variables will be set to 1.0.0, psychological-karson, e02bc6cd8ab3edd3d6e8874d1e97c08ef6c5db49 and 2020-02-01T22:35 respectively.

The Makefile in the project contains a sample configuration where the value is retrieved from the tool itself. For obvious reasons you should built a non-versioned binary before you can set the version in the build.

C/C++

For gcc you can use the -D flag to set defines at compile time. Use the tool to extract the version info. The Makefile in the project builds a Go executable and a gcc build should be quite similar.