gen-config binary added.

project.zsh

@@ -8,9 +8,9 @@ variables+=(
 	VARSTATEDIR '/var'
 )
 
-targets=(service status get-port)
+targets=(service status get-port gen-config)
 
-for target in service status get-port; do
+for target in service status get-port gen-config; do
 	type[$target]=crystal
 	sources[$target]=src/${target}.cr
 	depends[$target]=src/config.cr

shard.yml

@@ -15,6 +15,8 @@ targets:
 
 dependencies:
   specparser:
-      git: https://git.karchnu.fr/WeirdOS/recipes-parser
+    git: https://git.karchnu.fr/WeirdOS/recipes-parser
+  crinja:
+    github: straight-shoota/crinja
 
 license: MIT

src/gen-config.cr

@@ -0,0 +1,106 @@
+require "crinja"
+
+def sanitize_path(path)
+	path.gsub /\/\/+/, "/"
+end
+
+module Configure
+	def self.parse_options(unparsed : Array(String))
+		options = ARGV.map(&.split '=')
+
+		hash = Hash(String, String | Array(String) | Crinja::Callable::Instance | Hash(String, String)).new
+
+		options.each do |entry|
+			key, value = entry
+
+			old_value = hash[key]?
+
+			case old_value
+			when nil
+				hash[key] = value
+			when String
+				hash[key] = [old_value, value]
+			when Array(String)
+				old_value << value
+			end
+		end
+
+		hash
+	end
+end
+
+class Configure::Exception < Exception
+end
+
+class Configure::Context
+	getter root : String
+
+	def initialize(@root)
+	end
+
+	def generate(template, target : String, options : Hash(String, String | Array(String) | Crinja::Callable::Instance | Hash(String, String)))
+		target_file = File.open target, "w"
+
+		# FIXME: Alter default sources at build-time.
+		# FIXME: We’ll want a way to alter those context-wide.
+		sources = [
+			"/etc/templates",
+			"/usr/share/templates"
+		]
+
+		sources = sources
+			.map(&.+("/#{template}.j2"))
+			.map { |x| sanitize_path x }
+
+		source = sources.find do |source|
+			if File.exists? source
+				puts "Generating '#{target}' from '#{source}'"
+
+				next true
+			end
+		end
+
+		unless source
+			raise Exception.new "Could not find template to generate file ('#{target}')."
+		end
+
+		options["id"] = ENV["SERVICE_ID"]? || ""
+		options["environment"] = ENV["ENVIRONMENT"]? || ""
+		options["port"] = Crinja.function do
+			service = (arguments.varargs[0]? || "").to_s.gsub /\//, ':'
+			`get-port #{service}`
+		end
+
+		providers = {} of String => String
+		ENV["SERVICE_TOKENS"].try &.split(':').each do |token|
+			providers[token] = ENV["#{token.upcase}_PROVIDER"]? || ""
+		end
+		options["providers"] = providers
+
+		template = File.read source
+
+		target_file << Crinja.render(template, options)
+		target_file.close
+	end
+end
+
+template = ARGV[0]?
+target = ARGV[1]?
+
+if target.nil?
+	puts "usage: configure <template-name> <target> [option1=value1 [option2=value2 […]]]"
+	exit 1
+end
+
+ARGV.shift
+ARGV.shift
+
+options = Configure.parse_options ARGV
+
+begin
+	Configure::Context.new("/").generate(template, target, options)
+rescue e : Configure::Exception
+	STDERR.puts "Fatal error: #{e.message}"
+	exit 1
+end
+