Add functions part

content/en/docs/01/_index.md

@@ -1,88 +1,114 @@
 ---
-title: "1. Dagger Training Sample Chapter"
+title: "1. Functions and Chaining "
 weight: 1
 sectionnumber: 1
 ---
 
-## Title 1
+## 1. Functions and Chaining
 
-{{% alert title="Note" color="primary" %}}
-Sample Note
-{{% /alert %}}
+### Function Calls from the CLI
+
+The most common way to call Dagger Functions is using the `dagger` CLI:
 
-Sample code block:
 ```bash
-echo "Hello World!"
+dagger -m github.com/shykes/daggerverse/[email protected] call hello
 ```
 
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+The `dagger` CLI is first loads a `hello` module directly from its [GitHub repository](https://github.com/shykes/daggerverse/tree/main/hello) and then executes the `Hello()` function from that module.
 
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+After a while you should see:
 
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+```
+hello, world!
+```
 
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+{{% alert title="Note" color="primary" %}}
+Due to Daggers caching mechanism, subsequent calls will be executed much faster!
+{{% /alert %}}
 
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+### Exploring Modules and Functions
 
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+If you are curious, what other functions are available on this module, you can either have a look at its [source code](https://github.com/shykes/daggerverse/blob/main/hello/main.go) 
+or you can explore its functions using:
 
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+```bash
+dagger -m github.com/shykes/daggerverse/[email protected] functions
+```
 
+In this particular case, there aren't any other functions :( - but what about additional arguments of the `Hello()` function?
+Let's find out:
 
-## Title 2
+```bash
+dagger -m github.com/shykes/daggerverse/[email protected] call hello --help
+```
 
+{{% alert title="Note" color="primary" %}}
+Additional to the available arguments, this often also shows you the type of value a particular argument expects.
+{{% /alert %}}
 
-```yaml
-foo: bar
-```
 
+### Function Arguments
 
-## Task 1.1: Fix Deployment
+Dagger Functions can accept arguments. In addition to basic types (string, boolean, integer, array...), 
+Dagger also defines powerful core types: Directory, File, Container, Service, and Secret.
 
+#### String Arguments
 
-```yaml
-foo: bar
+To pass a string argument to a Dagger Function, append the corresponding flag to the dagger call command, followed by the string value:
+
+```bash
+dagger -m github.com/shykes/daggerverse/[email protected] call hello --name=sun
 ```
 
+#### Boolean Arguments
+
+To pass a boolean argument to a Dagger Function, simply add the corresponding flag:
+
+- To set the argument to true: `--foo=true`, or simply `--foo`
+- To set the argument to false: `--foo=false`
+
+#### Directory Arguments
+You can also pass a directory argument. To do so, add the corresponding flag, followed by a local filesystem path 
+**or** a remote Git reference. 
 
-## Task 1.2: Fix Release
+In **both** cases, the `dagger` CLI will convert it to an object referencing the contents of that filesystem path or Git repository location, 
+and pass the resulting `Directory` object as argument to the Dagger Function.
 
+#### Container Arguments
 
-```yaml
-foo: bar
+Same as directories, you can pass a container argument. To do so, add the corresponding flag, followed by the address of an OCI image. 
+
+The CLI will dynamically pull the image, and pass the resulting `Container` object as argument to the Dagger Function.
+
+```bash
+dagger -m github.com/jpadams/daggerverse/[email protected] call scan-container --ctr=alpine:latest
 ```
+{{% alert title="Note" color="primary" %}}
+It is important to know that in Dagger, a `Container` object is not merely a string referencing an image on a remote registry. 
+It is the **actual state of a container**, managed by the Dagger Engine, and passed to a Dagger Function's code as if it were just another variable!
+{{% /alert %}}
+
+#### Secret Arguments
 
+Dagger allows you to use confidential information, such as passwords, tokens, etc., in your Dagger Functions, without exposing them in plaintext logs, 
+writing them into the filesystem of containers you're building, or inserting them into the cache.
 
-## Task 1.3: Fix Release again
+To pass a secret to a Dagger Function, source it from a host environment variable `env:`, the host filesystem `file:`, or a host command `cmd:`.
 
+Here is an example of passing a GitHub access token from an environment variable named `GITHUB_TOKEN` to a Dagger Function. 
+The Dagger Function uses the token to query the GitHub CLI for a list of issues in the Dagger open-source repository:
 
-```yaml
-foo: bar
+```bash
+dagger -m github.com/aweris/daggerverse/gh@99a1336f8091ff43bf833778a324de1cadcf25ac call run --token=env:GITHUB_TOKEN --cmd="issue list --repo=dagger/dagger"
 ```
 
 
-## Task 1.4: Fix Release again and again
+### Task 1.1: Make use of arguments
 
+Call the `Hello()` function so that it returns the string `Welcome, sunshine!` in ASCII-art.
 
-```yaml
-foo: bart
+```bash
+dagger -m github.com/shykes/daggerverse/[email protected] call hello --giant --greeting=Welcome --name=sunshine
 ```
+