AuthProxy Plugin

There are many ways of authorizing an HTTP request. Often, this requires making IPC calls to some internal infrastructure. AuthProxy is a plugin that takes care of the Traffic Server end of authorizing a request and delegates the authorization decision to an external HTTP service.

This plugin can be used as either a global plugin or a remap plugin.

Note that Traffic Server optimizes latency by skipping the DNS lookup state if a document is found in the cache. This will have the effect of serving the document without consulting the AuthProxy plugin. you can disable this behavior by setting proxy.config.http.doc_in_cache_skip_dns to 0 in records.yaml.

Note that the authorization request will need to match a remap rule (which, as a standalone remap rule, does not need to call the AuthProxy plugin). If a second remap rule is required, by default, the authorization request will not have the same Host header as the request from the client. It could be added using the header_rewrite plugin (set-header Host "pristine_host.example.com").

Plugin Options

--auth-transform=TYPE

This option specifies how to route the incoming request to the authorization service. The transform type may be head or redirect.

If the transform type is head, then the incoming request is transformed to a HEAD request and is sent to the same destination. If the response is 200 OK, the incoming request is allowed to proceed.

If the transform type is range, then the incoming request is transformed to a Range request asking for 0 bytes. Other than that, the behavior is identical to the head option above. This type of Range request is useful when the upstream destination is a cache, and it's not able to cache HEAD requests.

If the transform type is redirect then the incoming request is sent to the authorization service designated by the --auth-host and --auth-port parameters. If the response is 200 OK, the incoming request is allowed to proceed.

When the authorization service responds with a status other than 200 OK, that response is returned to the client as the response to the incoming request. This allows mechanisms such as HTTP basic authentication to work correctly. Note that the body of the authorization service response is not returned to the client.

--auth-host=HOST

The name or address of the authorization host. This is only used by the redirect transform.

--auth-port=PORT

The TCP port of the authorization host. This is only used by the redirect transform.

--forward-header-prefix=PREFIX

If the option is enabled, authentication response header fields, which contain the specified prefix, will be sent to the original server in the original request.

--force-cacheability

If this options is set, the plugin will allow Traffic Server to cache the result of authorized requests. In the normal case, requests with authorization headers are nor cacheable, but this flag allows that by setting the proxy.config.http.cache.ignore_authentication option on the request.

--cache-internal

The option will allow the Traffic Server to cache internal requests. By default, internally generated requests are not cached as the agent needs to take the authorization decisions.

例

In this example, the authentication is performed by converting the incoming HTTP request to a HEAD request and sending that to the origin server origin.internal.com:

map http://cache.example.com http://origin.internal.com/ \
  @plugin=authproxy.so @pparam=--auth-transform=head

map http://origin.internal.com http://origin.internal.com/

In this example, the request is directed to a local authentication server that authorizes the request based on internal policy rules. Authentication response headers with the prefix will be proxied to the original server:

map http://cache.example.com http://origin.internal.com/ \
  @plugin=authproxy.so @pparam=--auth-transform=redirect @pparam=--auth-host=127.0.0.1 @pparam=--auth-port=9000 @pparam=--forward-header-prefix=x-requested

map http://origin.internal.com/ http://origin.internal.com/ \
  @plugin=authproxy.so @pparam=--auth-transform=redirect @pparam=--auth-host=127.0.0.1 @pparam=--auth-port=9000 @pparam=--forward-header-prefix=x-requested