Environment args (#70)

Add env for all arguments and info about env usage

README.md

@@ -84,6 +84,38 @@ If `redirect` option is provided, the server also listens on port 80 and redirec
 
 If the `--tls` option is provided, the Let's Encrypt Terms of Service are accepted automatically on your behalf. Please review them [here](https://letsencrypt.org/repository/). Certificates are cached in a `.certs` folder created where you are executing `mbtileserver`. Please make sure this folder can be written by the `mbtileserver` process or you will get errors.
 
+Also you can set up server config by environment variables. It may be helpful, when you deploying it in docker image. Just now exists next variables:
+-   PORT
+-   TILE_PATH
+-   PRIVATE_KEY
+-   PATH_PREFIX
+-   DOMAIN
+-   SENTRY_DSN
+-   VERBOSE
+-   AUTO_TLS
+-   REDIRECT
+
+Simple example:
+
+```
+$ PORT=7777 TILE_PATH=./path/to/your/tiles VERBOSE=true mbtileserver
+```
+
+In docker-compose.yml file it will be look like:
+
+```
+mbtileserver:
+  ...
+
+  environment:
+    PORT: 7777
+    TYLE_PATH: "./path/to/your/tiles"
+    VERBOSE: true
+  entrypoint: mbtileserver
+
+  ...
+```
+
 ## Specifications
 
 -   expects mbtiles files to follow version 1.0 of the [mbtiles specification](https://github.com/mapbox/mbtiles-spec). Version 1.1 is preferred.

main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"strconv"
 
 	"golang.org/x/crypto/acme/autocert"
 
@@ -63,6 +64,58 @@ func init() {
 	flags.BoolVarP(&autotls, "tls", "t", false, "Auto TLS via Let's Encrypt")
 	flags.BoolVarP(&redirect, "redirect", "r", false, "Redirect HTTP to HTTPS")
 
+	if env := os.Getenv("PORT"); env != "" {
+		p, err := strconv.Atoi(env)
+		if err != nil {
+			log.Fatalln("PORT must be a number")
+		}
+		port = p
+	}
+
+	if env := os.Getenv("TILE_PATH"); env != "" {
+		tilePath = env
+	}
+
+	if env := os.Getenv("PRIVATE_KEY"); env != "" {
+		privateKey = env
+	}
+
+	if env := os.Getenv("PATH_PREFIX"); env != "" {
+		pathPrefix = env
+	}
+
+	if env := os.Getenv("DOMAIN"); env != "" {
+		domain = env
+	}
+
+	if env := os.Getenv("SENTRY_DSN"); env != "" {
+		sentryDSN = env
+	}
+
+	if env := os.Getenv("VERBOSE"); env != "" {
+		p, err := strconv.ParseBool(env)
+		if err != nil {
+			log.Fatalln("VERBOSE must be a bool(true/false)")
+		}
+		verbose = p
+	}
+
+	if env := os.Getenv("AUTO_TLS"); env != "" {
+		p, err := strconv.ParseBool(env)
+		if err != nil {
+			log.Fatalln("AUTO_TLS must be a bool(true/false)")
+		}
+		autotls = p
+	}
+
+	if env := os.Getenv("REDIRECT"); env != "" {
+		p, err := strconv.ParseBool(env)
+		if err != nil {
+			log.Fatalln("REDIRECT must be a bool(true/false)")
+		}
+		redirect = p
+	}
+
 	if secretKey == "" {
 		secretKey = os.Getenv("MBTILESERVER_SECRET_KEY")
 	}