Add some more docs on running triagebot.

README.md

@@ -7,21 +7,65 @@ if you find something helpful!
 
 [wiki]: https://github.com/rust-lang/triagebot/wiki
 
+## How triagebot works
+
+Triagebot consists of a webserver with several endpoints.
+The `/github-hook` and `/zulip-hook` endpoints receive webhook notifications from the respective services.
+Triagebot can then respond to those notifications to perform various actions such as adjusting labels.
+
+The Triagebot webserver also includes several other endpoints intended for users to access directly, such as https://triage.rust-lang.org/agenda.
+
+Triagebot uses a Postgres database to retain some state.
+In production, it uses [RDS](https://aws.amazon.com/rds/).
+
+The server at https://triage.rust-lang.org/ runs on ECS and is configured via [Terraform](https://github.com/rust-lang/simpleinfra/blob/master/terraform/shared/services/triagebot/main.tf#L8).
+Updates are automatically deployed when merged to master.
+
 ## Installation
 
 To compile the Triagebot you need OpenSSL development library to be installed (e.g. for Ubuntu-like Linux distributions `sudo apt install libssl-dev`).
 
 Run `cargo build` to compile the triagebot.
 
-The `GITHUB_WEBHOOK_SECRET`, `GITHUB_API_TOKEN` and `DATABASE_URL` environment
-variables need to be set.
+## Running triagebot
+
+It is possible to run triagebot yourself, and test changes against your own repository.
+Some developers may settle with testing in production as the risks tend to be low, but the more intrepid may find it easier to iterate separately.
+
+The general overview of what you will need to do:
+
+1. Install Postgres. Look online for any help with installing and setting up Postgres (particularly if you need to create a user and set up permissions).
+2. Create a database: `createdb triagebot`
+3. Provide a way for GitHub to access the Triagebot webserver.
+   There are various ways to do this (such as placing it behind a proxy, or poking holes in your firewall).
+   Or, you can use a service such as https://ngrok.com/ to access on your local dev machine via localhost.
+   Installation is fairly simple, though requires setting up a (free) account.
+   Run the command `ngrok http 8000` to forward to port 8000 on localhost.
+4. Create a GitHub repo to run some tests on.
+5. Configure the webhook in your GitHub repo.
+   I recommend at least skimming the [GitHub webhook documentation](https://docs.github.com/en/developers/webhooks-and-events/webhooks/about-webhooks) if you are not familiar with webhooks. In short:
+
+   1. Go to the settings page.
+   2. Go to the webhook section.
+   3. Click "Add webhook"
+   4. Include the settings:
+
+      - Payload URL: This is the URL to your Triagebot server, for example http://7e9ea9dc.ngrok.io/github-hook. This URL is displayed when you ran the `ngrok` command above.
+      - Content type: application/json
+      - Secret: Enter a shared secret (some longish random text)
+      - Events: "Send me everything"
+6. Configure the `.env` file:
 
-If `GITHUB_API_TOKEN` is not set, the token can also be stored in `~/.gitconfig` in the
-`github.oauth-token` setting.
+   1. Copy `.env.sample` to `.env`
+   2. `GITHUB_API_TOKEN`: This is a token needed for Triagebot to send requests to GitHub. Go to GitHub Settings > Developer Settings > Personal Access Token, and create a new token. The `repo` permission should be sufficient.
+      If this is not set, Triagebot will also look in `~/.gitconfig` in the `github.oauth-token` setting.
+   3. `DATABASE_URL`: This is the URL to the Postgres database. Something like `postgres://eric@localhost/triagebot` should work, replacing `eric` with your username.
+   4. `GITHUB_WEBHOOK_SECRET`: Enter the secret you entered in the webhook above.
+   5. `RUST_LOG`: Set this to `debug`.
 
-To configure the GitHub webhook, point it to the `/github-hook` path of your
-webserver (by default `http://localhost:8000`), configure the secret you chose
-in `.env`, set the content type to `application/json` and select all events.
+7. Run `cargo run --bin triagebot`. This starts the http server listening on port 8000.
+8. Add a `triagebot.toml` file to the main branch of your GitHub repo with whichever services you want to try out.
+9. Try interacting with your repo, such as issuing `@rustbot` commands or interacting with PRs and issues (depending on which services you enabled in `triagebot.toml`). Watch the logs from the server to see what's going on.
 
 ## License