I'm trying to create a web interface for a data analysis pipeline using Pyramid. I'm using deform and colander to make the forms. I've been adapting this example:

http://pyramid-tutorials.readthedocs.org/en/latest/humans/security/step02/

Most of the work gets done when a form gets submitted, but there are a couple of generic steps that only need to run once. Can I load some things into memory when the server starts up so that they are accessible from within a view?

You can define some module level variables in the main file of your application (or may be somewhere else) and then use them by importing them as per your requirement.

I use this method to create settings like database connection string for SQLAlchemy from environment variables.

By default, a module will be parsed only once in Python, so you module level code will run only once.

Update 1

Let's assume directory structure of a pyramid project looks like this:

.
├── __init__.py
├── models
│   ├── __init__.py
│   ├── meta
│   │   ├── base.py
│   │   ├── __init__.py
│   │   ├── orm.py
│   │   ├── schema.py
│   │   ├── types.py
│   ├── users.py
├── security.py
├── settings
│   ├── database.py
│   ├── email.py
│   ├── __init__.py
│   ├── redis.py
│   ├── security.py
├── static
│   ├── css
│   │   └── main.css
│   └── js
│       ├── app.js
│       ├── app-services.js
│       ├── controllers
│       │   └── excel_preview.js
├── templates
│   ├── auth
│   │   └── login.html
│   ├── base.html
│   ├── home.html
├── views
│   ├── auth.py
│   ├── home.py
│   ├── __init__.py

Let's say we've following code in settings/redis.py:

import os
import redis


def get_redis_client():
    # Read settings from environment variables
    redis_db_name = os.environ.get('REDIS_NAME')
    redis_host = os.environ.get('REDIS_HOST')
    redis_port = os.environ['REDIS_PORT']

    # create a redis connection
    redis_client = redis.StrictRedis(
        host=redis_host,
        port=redis_port,
        db=redis_db_name,
    )

    # return newly created redis connection
    return redis_client


redis_client = get_redis_client()

SOME_SETTING_STORED_IN_REDIS = redis_client.get('some_setting_stored_in_redis')

You can use this SOME_SETTING_STORED_IN_REDIS variable from anywhere. If name of your app is example_app then in example_app/views/home.py you can use it like this:

from pyramid.view import view_config

from example_app.settings.redis import SOME_SETTING_STORED_IN_REDIS


def includeme(config):
    config.add_route('home', '/')


@view_config(
    route_name='home',
    renderer='home.html',
    permission='authenticated'
)
def home_view(request):

    return {
        "some_setting": SOME_SETTING_STORED_IN_REDIS,
    }

I think you're trying to achieve something similar.