Updated readme

README.rst

@@ -2,7 +2,7 @@
  pubtools-sign
 ===============
 
-Set of scripts used for signing 
+Set of scripts used for signing artifacts via configured signers 
 
 
 Requirements
@@ -28,3 +28,40 @@ Setup
 
 Usage
 =====
+
+::
+
+  $ pubtools-sign --help
+  $ pubtools-sign-clearsign --help
+  $ pubtools-sign-containersign --help
+
+Configuration
+=============
+
+Configuration is done via a yaml file. The default location is `~/.config/.pubtools-sign/conf.yaml` or `/etc/pubtools-sign/conf.yaml`. You can also specify a custom location via the `--config` argument. The configuration file is divided into sections, each section is a signer. Each signer has a set of attributes that are used to configure the signer
+Conf.yaml has following structure:::
+
+  msg_signer:
+    messaging_brokers:
+      - <protocol://<host>:<port> for messaging broker
+    messaging_cert_key: <path to messaging client key + certificate in PEM format>
+    messaging_ca_cert: <path to CA certificate bundle>
+    topic_send_to: topic://<topic> - topic where to send signing requests
+    topic_listen_to: queue://<queue> - queue where to listen for answers from signing server. Supported templating variables: {creator - UID from client cert}, {task_id}
+    environment: <env> - environment attribute which is included in signing request
+    service: <service> - service attribute which is included in signing request
+    timeout: <int> - timeout for signing request
+    retries: <int> - number of retries for receiving signing responses from messaging brokers
+    send_retries: <int> - number of retries for whole send + receive cycle
+    message_id_key: <id> - attribute in message response used as unique identifier for signing request
+    log_level: <level> - log level for pubtools-sign
+  cosign_signer:
+    rekor_url: <rekor-url>
+    upload_tlog: <true|false>
+    registry_user: <user> - used to login to registry where images will be signed
+    registry_password: <password>
+    env_variables:
+      <key>: <val> - mapping of environment variables used in signing process. This can be used for example for AWS setup
+    key_aliases:
+      <alias>: <key> - mapping of key aliases to actual keys. When passing alias as signing key, <key> is used instead. This
+                       way you cna define for example "prod-key" alias and have different real keys for different signers