chore: add "Authentication" readme section

readme.md

@@ -18,16 +18,17 @@ There are two approaches in providing `cfw` with a set of Cloudflare credentials
 
 Create a `~/.cfw/config` file, where `~` is that path to your home directory. Inside, you'll store your credentials under different "profile" namespaces. (If you're familiar, this is very similar to an AWS credentials file.) An example file may look like this:
 
-```
+```ini
 [personal]
 CLOUDFLARE_AUTH_EMAIL = [email protected]
 CLOUDFLARE_ACCOUNTID = ACCOUNTID_VALUE
 CLOUDFLARE_AUTH_KEY = GLOBAL_API_KEY
+CLOUDFLARE_ZONEID = ZONEID_VALUE
 ```
 
-In this case, we have a "personal" profile containing our personal account credentials, for example. You can define multiple credential groups by repeating this template as needed, using different profile names.
+In this case, we have a "personal" profile containing our personal account credentials. You can define multiple credential groups by repeating this template as needed, using different profile names.
 
-```sh
+```ini
 [personal]
 CLOUDFLARE_AUTH_EMAIL = [email protected]
 # ...
@@ -41,7 +42,7 @@ Additionally, all credential key names may be lowercased.
 
 ***Default Profile***
 
-If a profile named "default" exists, then `cfw` will auto-load that credentials group when no there is no profile configured.
+If a profile named `[default]` exists, then `cfw` will auto-load that credentials group when no there is no profile configured.
 
 ***Selecting a Profile***
 
@@ -55,6 +56,39 @@ The same keys found within your credentials file may be used again as environmen
 
 When defined, an environment variable takes priority over all other configuration avenues.
 
+* `CLOUDFLARE_ACCOUNTID` – your account identifier; alias of `config.accountid`
+* `CLOUDFLARE_AUTH_EMAIL` – your account email address; alias of `config.email`
+* `CLOUDFLARE_AUTH_KEY` – your account's global API key; alias of `config.authkey`
+* `CLOUDFLARE_ZONEID` – your domain/zone's identifier; alias of `config.zoneid`
+* `CLOUDFLARE_TOKEN` – an API access token; alias of `config.token`
+
+### Authentication
+
+In order to successfull access your Cloudflare account's resources, you must satisfy the following requirements:
+
+1. A `CLOUDFLARE_ACCOUNTID` (or `config.accountid`) is **always required**.
+
+2. A valid token or key-pair; you have two options:
+    1. A `CLOUDFLARE_TOKEN` (or `config.token`) containing a valid [API token](https://dash.cloudflare.com/profile/api-tokens). <br>_***(Recommended)*** Preferred solution, as this API token can be narrowly scoped and can be revoked at any time._
+
+    2. A valid `CLOUDFLARE_AUTH_EMAIL` _and_ `CLOUDFLARE_AUTH_KEY` combination. <br>_This requires your Global API Key, which grants full access to all account resources._
+
+3. A `CLOUDFLARE_ZONEID` is **only required if** you are not deploying to a `*.workers.dev` subdomain (via `config.subdomain`).
+
+The following profiles represent valid combinations:
+
+```ini
+[recommended]
+cloudflare_accountid = da32...
+cloudflare_token = 78a...
+# (optional) cloudflare_zoneid = b58...
+
+[other]
+cloudflare_accountid = da32...
+cloudflare_auth_email = [email protected]
+cloudflare_auth_key = 62d...
+# (optional) cloudflare_zoneid = b58...
+```
 
 <!-- TODO: auth + email vs token -->