pomerium/docs/docs/topics/programmatic-access.md
bobby 8b68079488
docs: rename docs/reference to docs/topics (#1182)
* docs: rename docs/reference to docs/topics
Signed-off-by: Bobby DeSimone <bobbydesimone@gmail.com>
2020-08-01 10:00:14 -07:00

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---
title: Programmatic access
description: >-
This article describes how to configure pomerium to be used to enable
machine-to-machine programmatic access.
---
# Programmatic access
This page describes how to obtain Pomerium access credentials programmatically via a web-based oauth2 based authorization flow. If you have ever used Google's `gcloud` commandline app, the mechanism is very similar.
## Components
### Login API
The API returns a signed, sign-in url that can be used to complete a user-driven login process with Pomerium and your identity provider. The Login API endpoints takes a `redirect_uri` query param as an argument which points to the location of the callback server to be called following a successful login.
For example:
```bash
$ curl "https://httpbin.example.com/.pomerium/api/v1/login?redirect_uri=http://localhost:8000"
https://authenticate.example.com/.pomerium/sign_in?redirect_uri=http%3A%2F%2Flocalhost%3Fpomerium_callback_uri%3Dhttps%253A%252F%252Fhttpbin.corp.example%252F.pomerium%252Fapi%252Fv1%252Flogin%253Fredirect_uri%253Dhttp%253A%252F%252Flocalhost&sig=hsLuzJctmgsN4kbMeQL16fe_FahjDBEcX0_kPYfg8bs%3D&ts=1573262981
```
### Callback handler
It is the script or application's responsibility to create a HTTP callback handler. Authenticated sessions are returned in the form of a [callback](https://developer.okta.com/docs/concepts/auth-overview/#what-kind-of-client-are-you-building) from pomerium to a HTTP server. This is the `redirect_uri` value used to build Login API's URL, and represents the URL of a (usually local) http server responsible for receiving the resulting user session in the form of `pomerium_jwt` and `pomerium_refresh_token` query parameters.
See the python script below for example of how to start a callback server, and store the session payload.
## Handling expiration and revocation
Your application should handle token expiration. If the session expires before work is done, the identity provider issued `refresh_token` can be used to create a new valid session.
Also, your script or application should anticipate the possibility that a granted `refresh_token` may stop working. For example, a refresh token might stop working if the underlying user changes passwords, revokes access, or if the administrator removes rotates or deletes the OAuth Client ID.
## High level workflow
The application interacting with Pomerium must manage the following workflow. Consider the following example where a script or program desires delegated, programmatic access to the domain `httpbin.corp.domain.example`:
1. The script or application requests a new login url from the pomerium managed endpoint (e.g. `https://httpbin.corp.domain.example/.pomerium/api/v1/login`) and takes a `redirect_uri` as an argument.
1. The script or application opens a browser or redirects the user to the returned login page.
1. The user completes the identity providers login flow.
1. The identity provider makes a callback to pomerium's authenticate service (e.g. `authenticate.corp.domain.example`) .
1. Pomerium's authenticate service creates a user session and redirect token, then redirects back to the managed endpoint (e.g. `httpbin.corp.domain.example`)
1. Pomerium's proxy service and makes a callback request to the original `redirect_uri` with the user session and refresh token as arguments.
1. The script or application is responsible for handling that http callback request, and securely handling the callback session (`pomerium_jwt`) and refresh token (`pomerium_refresh_token`) queryparams.
1. The script or application can now make any requests as normal, by setting the `Authorization: Pomerium ${pomerium_jwt}` header.
## Example Code
Please consider see the following minimal but complete python example.
```bash
python3 scripts/programmatic_access.py \
--dst https://httpbin.example.com/headers
```
<<< @/scripts/programmatic_access.py
[authorization bearer token]: https://developers.google.com/gmail/markup/actions/verifying-bearer-tokens
[identity provider]: ../identity-providers/readme.md
[proof key for code exchange]: https://tools.ietf.org/html/rfc7636