Update documentation and Dockerfilev0.3.0

1 files changed, 30 insertions, 21 deletions

diff --git a/README.md b/README.md
index fee26c7..a3e6e4a 100644
--- a/README.md
+++ b/README.md
@@ -3,29 +3,38 @@
 A thing that tells `go get` where to get Go packages and redirects users
 to https://godoc.org.
 
-You need to set up the following environment variables for it to work:
+## systemd Configuration
 
-* `DEST` for the base URL that will be used to build the repository URL,
-* `PREFIX` for the prefix that must be removed from your package name,
-  e.g. `golang.org/x/` for `golang.org/x/image`, and
-* `VCS` for the type of VCS you are using, e.g. `git`.
+`go-import-redirect` takes the following flags:
 
-There are three modes of operation:
+* `-addr` for the address on which `go-import-redirect` should listen.
+  It can either be a normal `IP:PORT` address or an absolute path to a
+  UNIX socket that will be created. Defaults to `localhost:8080`. See
+  https://golang.org/pkg/net/#Dial for more details.
+* `-from` for the prefix that must be removed from your package name,
+  e.g. `golang.org/x/` for `golang.org/x/image`.
+* `-to` for the URL that will be used to build the repository URL.
+* `-vcs` for the type of VCS you are using, e.g. `git`. Defaults to
+  `git`.
 
-1. **As a systemd service.** In this mode, it is recommended to enable
-   the companion systemd socket and configure that. systemd will only
-   start the service when needed. If you are not using the companion
-   systemd socket but rather the systemd service directly, you will need
-   to set the `ADDR` environment variable to tell go-import-redirect how
-   to listen for incoming connections. If `ADDR` is set and starts with
-   `/`, go-import-redirect will treat it as a UNIX socket path. If
-   `ADDR` is not set, it will default to `:8080`. See
-   https://golang.org/pkg/net/#Dial for more details.
+It is recommended to enable the companion systemd socket and customize
+it so systemd can start the service when needed and pass the socket to
+`go-import-redirect`.
 
-2. **Inside a Docker container.** In this mode, the port 8080 will be
-   exposed and no other environment variable besides the ones above need
-   to be set.
+Likewise, you must customize the service definition to pass the right
+flag values.
 
-3. **As an AWS Lambda.** This is very similar to Docker. You will need
-   to set the environment variables above. Note that this version needs
-   to be compiled as a Linux binary and with the `aws` build tag set.
+## AWS Lambda Configuration
+
+The AWS Lambda version requires the use of the following environment
+variables: `FROM`, `TO`, and `VCS`. Those have the same semantics as the
+flags described above.
+
+Note that this version needs to be compiled as a Linux binary and with
+the `aws` build tag set.
+
+## Docker Configuration
+
+You can build the Docker image as usual, and pass the `-from`, `-to`,
+and `-vcs` flags when you invoke `docker run`. The `-addr` flag is
+already set to an appropriate value in the Dockerfile.