iivvoo / cubric

Pythonic and flexible project deployments

Cubric

Cubric attempts to make creating deployments easier. It lives somewhere between Fabric and Ansible: it aims for Fabric's programmability and Ansible's idempotent declarative modules / commands, all while being high level and pythonic.

WARNING Cubric is incomplete, unstable, very alpha and not usable for anyone but me. What are you doing here anyway?

Sample

A code snippet says more than a thousand words.

class DjangoProjectDeployment(DeploymentBase):

    requires = (Venv, Template, Supervisor, File, NGINX, Git, Postgres)

    def setup_database(self, env):
        self.postgres.user(self.config.db_user, self.config.db_pass)
        self.postgres.database(self.config.db_name, self.config.db_user)

    def git_buildout(self, env):
        self.git.cloneup(self.config.repo, self.config.project)

        env.chdir(self.config.project)
        self.venv.create() \
            .create() \
            .install("zc.buildout==2.5.0") \
            .install("setuptools")

        env.command("bin/buildout", "-c", "development.cfg")

    def django_update(self, env):
        """ update database, etc """
        env.chdir(pj(self.config.instancepath, self.config.project))
        env.command("bin/django", "migrate")

    def run(self, env):

        self.setup_database(env)

        env.set("DATABASE_URL", self.config.database_url)

        env.mkdir(self.config.instancepath, chdir=True)

        self.git_buildout(env)

        self.django_update(env)

        env.chdir(self.config.instancepath)

        for d in ("logs", "run", "static", "media", "www"):
            env.mkdir(pj(self.config.instancepath, d))
        with env.sudo():
            self.file.present(pj(self.config.instancepath, "run"),
                              type=File.DIR,
                              mode="2770",
                              group="www-data")

        svcpath = pj(self.config.instancepath, "supervisor.conf")
        nginxpath = pj(self.config.instancepath, "nginx.conf")
        self.template \
            .create(src="templates/supervisor.conf",
                    dst=svcpath,
                    args=self.config) \
            .create(src="templates/uwsgi.conf",
                    dst=pj(self.config.instancepath, "uwsgi.conf"),
                    args=self.config) \
            .create(src="templates/nginx.conf",
                    dst=nginxpath,
                    args=self.config)
        self.supervisor.install(svcpath, self.config.projectid)

        self.nginx.install(nginxpath, self.config.projectid)

The class above will, if configured/invoked correctly git clone/update a repo, run buildout, setup database, supervisor, nginx and uwsgi on a remote host.

Issue's, todo's

env.last_result holds the result of the last action but it's currently only used by Template.create, and it doesn't get reset between action calls.

Either give up on chaining and just return results or have actions require a decorator that sets/clears last_result?

Currently we mostly execute remote shell commands. This is rather primitive, difficult to parse and it's not always possible/easy to use full shell constructs (e.g. pipes, redirection)

Life would be much easier if we could invoke python remotely. A possiblity for this might be a remove server/daemon (that's started/stopped by cubric on demand) that communicates/forwards over an ssh-tunneled port