cmd/dendrite: Add first shot at new single-binary CLI usage

src/github.com/matrix-org/dendrite/cmd/dendrite/main.go

@@ -0,0 +1,69 @@
+// Copyright 2017 Vector Creations Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"fmt"
+
+	"github.com/docopt/docopt-go"
+)
+
+func main() {
+	usage := `
+Usage:
+    dendrite serve all [options]
+    dendrite serve <server-type> [options]
+    dendrite -V
+    dendrite -h
+
+Arguments:
+    <server-type>   One of: client-api, room-server, sync-api.
+
+Options:
+    -c <config-file>, --config-file=<config-file>
+        Path to a YAML-format configuration file.
+    -H <host>, --host=<host>
+        Host to bind. The port is optional and ignored for 'serve all'. The
+        default ports are: 7776 (sync-api), 7777 (room-server), and 7778 (client-api)
+        [default: "localhost"]
+    -h, --help
+        Print this usage text.
+    -k <kafka-hosts>, --kafka-hosts=<kafka-hosts>
+        A comma-separated list of Kafka hosts. [default: "localhost:9092"]
+    -l <log-dir>, --log-dir=<log-dir>
+        Path to log directory. If not set, logs will only be written to stderr.
+    -r <room-server-host>, --room-server-host=<room-server-host>
+        Host of the room server. [default: "localhost:7777"]
+    -t <topic-prefix>, --topic-prefix=<topic-prefix>
+        Prefix for Kafka topics used for inter-component communication.
+        [default: ""]
+    -V, --version
+        Print the dendrite version.
+
+Environment Variables:
+    PostgreSQL MUST be configured using the standard libpq environment variables:
+        https://www.postgresql.org/docs/current/static/libpq-envars.html
+    Required:
+        PGPASSWORD
+        PGHOST
+    Optional:
+        PGUSER      Defaults to "postgres"
+        PGSSLMODE   Defaults to "disabled"
+`
+
+	arguments, _ := docopt.Parse(usage, nil, true,
+		"dendrite Matrix homeserver, version 0.0.1", false)
+	fmt.Println(arguments)
+}