envstack 0.2.0

Stacked environment variable management system.

envstack

Stacked environment variable management system. The lightweight, easy to use "rez" alternative for production pipelines.

Environment variables are declared in namespaced .env files using yaml syntax. The default stack is stack and variables are declared in stack.env files. You can create any new stack by creating new .env files, e.g. creating a new test stack just create test.env files.

Envstack works best combined with siteconf.

Quickstart

To create a new environment stack, create a new namespaced .env file. For example, here is a simple thing.env file (the stack namespace is "thing"):

all: &default
  FOO: bar

To see the resolved environment for the thing environment stack, run:

$ envstack thing
FOO 'bar'

Environment stacks are hierarchical, so values for $FOO defined in .env files lower in the filesystem (lower in scope) override those defined higher up (higher in scope):

/show/thing.env
/show/seq/thing.env
/show/seq/shot/thing.env
/show/seq/shot/task/thing.env

Variables can reference other variables defined elsewhere (but cannot be circular):

all: &default
  BAR: $FOO

Variables can be platform specific (and inherit the defaults):

linux:
  <<: *default
  HELLO: world

Environment files can include other namespaced environments:

include: ['other']

Installation

The easiest way to install:

$ pip install envstack

Usage

To see the default resolved environment for any given scope (directory):

$ envstack

To see the resolved environment for a given namespace.

$ envstack <stack> [OPTIONS]

To resolve a $VAR declaration for a given environment stack:

$ envstack <stack> -r <VAR>

To trace where a $VAR declaration is being set:

$ envstack <stack> -t <VAR>

To see an environment stack on another platform:

$ envstack <stack> -p <platform>

Running Commands

To run any command line executable inside of an environment stack, where <command> is the command to run:

$ enstack <stack> -- <command>

For example, running python in the default stack (reading from the default stack.env file):

$ envstack -- python -c "from envstack.env import environ; print(environ['HELLO'])"
world

Same command but using the "thing" stack"

$ envstack thing -- python -c "from envstack.env import environ; print(environ['FOO'])"
bar