Schema validation: update HTTP sample

Author: andreyaksenov

doc/code_snippets/snippets/config/instances.enabled/application_role_http_api/http-api.lua

@@ -1,14 +1,37 @@
 -- http-api.lua --
 local httpd
 local json = require('json')
+local schema = require('experimental.config.utils.schema')
 
-local function validate(cfg)
-    if cfg.host then
-        assert(type(cfg.host) == "string", "'host' should be a string containing a valid IP address")
+local function validate_host(host, w)
+    local host_pattern = "^(%d+)%.(%d+)%.(%d+)%.(%d+)$"
+    if not host:match(host_pattern) then
+        w.error("'host' should be a string containing a valid IP address, got %q", host)
+    end
+end
+
+local function validate_port(port, w)
+    if port <= 1 or port >= 65535 then
+        w.error("'port' should be between 1 and 65535, got %d", port)
     end
-    if cfg.port then
-        assert(type(cfg.port) == "number", "'port' should be a number")
-        assert(cfg.port >= 1 and cfg.port <= 65535, "'port' should be between 1 and 65535")
+end
+
+local listen_address_schema = schema.new('listen_address', schema.record({
+    host = schema.scalar({
+        type = 'string',
+        validate = validate_host,
+    }),
+    port = schema.scalar({
+        type = 'integer',
+        validate = validate_port,
+    }),
+}))
+
+local function validate(cfg)
+    if cfg.host and cfg.port then
+        listen_address_schema:validate(cfg)
+    else
+        error("You need to set both host and port values")
     end
 end