update service guide

docs/guide/walkthrough/services.md

@@ -2,11 +2,12 @@
 sidebar_position: 6
 ---
 
+# Services
+
 :::tip
 This is version 3 api only!!
 :::
 
-# Services
 
 :::tip
 TLDR: The direct upgrade to useContainer. if you set up a bot with create-bot, check dependencies.d.ts. 
@@ -48,14 +49,73 @@ export default commandModule({
 })
 ```
 
-## Safety
-- Services cannot be called in other services while makeDependencies is forming.
-- You will need to wire dependencies together.
 
 import Tabs from '@theme/Tabs';
 import TabItem from '@theme/TabItem';
 
 
+## Safety
+- Services cannot be called in other services while makeDependencies is forming.
+
+<Tabs>
+
+<TabItem value="good" label="A good example">
+
+Lets pass a logger into our database.
+```ts title="index.ts" showLineNumbers
+await makeDependencies({ 
+    build: root => root
+        //Overriding the default logger provided.
+        .upsert({ '@sern/logger': single(() => new Logger()) })
+
+        // Wiring our logger into the database.
+        .add(ctx =>  {
+            return { database: single(() => new Database(ctx['sern/logger']))) }
+        })
+})
+```
+</TabItem>
+
+<TabItem value="bad" label="Don't do this">
+
+```ts title="index.ts" showLineNumbers
+await makeDependencies({ 
+    build: root => root
+        //Overriding the default logger provided.
+        .upsert({ '@sern/logger': single(() => new Logger()) })
+
+        // Wiring our logger into the database.
+        // We wire our database incorrectly. Logger should be passed INTO the constructor
+        .add({ database: single(() => new Database()) })
+})
+```
+
+```ts title="index.ts" showLineNumbers
+import { Service, makeDependencies } from '@sern/handler';
+
+//Calling Service prematurely!
+const logger = Service('@sern/logger');
+
+class Database {
+    
+    constructor() {
+        this.logger = logger
+    }
+}
+```
+This is a code smell anyway. It breaks encapsulation and defeats the purpose of wiring dependencies
+</TabItem>
+</Tabs>
+
+- Services can only be used after sern has made dependencies. 
+    - Calling a service before will crash your application. 
+- Services can be safely used outside of commandModules. 
+    - Be careful to not cause too many side effects.
+
+
+
+- You will need to wire dependencies together.
+
 <Tabs>
 <TabItem value="good" label="A good example">
 
@@ -67,6 +127,7 @@ await makeDependencies(...pass your options here)
 import { Service } from '@sern/handler';
 const client = Service('@sern/client');
 ```
+
 </TabItem>
 
 <TabItem value="bad" label="Don't do this">