Add client documentation

README.md

@@ -26,4 +26,12 @@ Other important files are:
 - [setup.cfg](./setup.cfg): Configuration file for defining the metadata of the Python project typically used by setuptools.
 
 ## Documentation
-The documenation of the Security Tracker itself, can be found in the [docs/](./docs/) directory.
+
+### Client
+
+The client documentation can be found here: [docs/01_client.md](./docs/01_client.md)
+
+### Server
+
+
+### Ingestion

docs/01_client.md

@@ -0,0 +1,53 @@
+# Client
+
+The Garden Linux Security Tracker `glvd` can be access either via a simple HTTP client or it can be access via Garden Linux own Security Tracker Client.
+
+## HTTP Client
+
+The Garden Linux Security Tracker provides API endpoints that can be access with every HTTP client. A user can access it via `curl` for example, which would look like this:
+```bash
+$ curl -s http://glvd.gardenlinux.io/<API ENDPOINT>
+$ curl -s http://glvd.gardenlinux.io/v1/cves/CVE-2019-13057
+```
+The HTTP server will return a JSON output which could be parsed by tools like `jq` for example.
+Which API endpoint exists can be read in the corresponding API specification. This can be found here: [openapi-v1.yaml](../openapi-v1.yaml)
+
+## GLVD Client
+This repository offers a lightwight `glvd` client written in Python with which a user can send request to the `glvd` API endpoints. In order to run this client, some prerequisites must be fulfilled on the client's system before executing the corresponding client.
+
+### Prerequisites
+
+In order to run the `glvd` client, one must ensure that the following packages are installed
+```bash
+$ apt update
+$ apt install -y git python3-pip python3-apt
+```
+
+After that, the actual client can be installed
+```bash
+$ pip install git+https://github.com/gardenlinux/glvd --system-break-packages
+```
+
+### Execution
+
+The Garden Linux Security Tracker client offers two modes:
+
+##### CVE Mode:
+```bash
+$ glvd cve <CVE>
+$ glvd cve CVE-2019-13057 --server http://glvd.gardenlinux.io
+```
+This mode allows you to get information about a given CVE as long as Garden Linux is affected by this CVE. If Garden Linux is not affected by this, the client will return the following message: 
+* `CVE-2019-13058 not found`
+
+The CVE information is returned in JSON format so the output can be parsed with tools like `jq` for example.
+
+##### CVE APT Mode:
+```bash
+$ glvd cve-apt --server http://glvd.gardenlinux.io
+```
+This mode returns all CVEs to all packages installed on the local system. The system itself must fullfill the following criteria:
+* Debian: Buster, Bullseye, Bookworm or Trixie
+* Garden Linux: >= 1337.0
+
+Thereby, the client returns a list of CVEs in JSON format. This output can then be parsed by tools like `jq` for example.