# device-inventory

A lightweight hardware inventory tracker built in C++17.
Uses a **client/server** model: the server owns the file-backed database and
exposes a TCP interface on localhost; the CLI client connects to it to run
commands.

---

## Architecture

```
┌──────────────┐  TCP (localhost:9876)  ┌─────────────────────┐
│ inventory-cli│ ─────────────────────► │ inventory-server    │
│  (CLI client)│ ◄───────────────────── │  database ► file.db │
└──────────────┘                        └─────────────────────┘
```

* **inventory-server** – loads the inventory file on start, accepts one
  command per connection, and flushes changes to disk after every mutation.
* **inventory-cli** – a thin CLI that translates subcommands into protocol
  messages, connects to the server, and pretty-prints the response.

---

## Build

Requires CMake ≥ 3.16 and a C++17-capable compiler.

```bash
cd device-inventory
cmake -S . -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build
```

Binaries end up in `build/inventory-server` and `build/inventory-cli`.

---

## Running

### Start the server

```bash
./build/inventory-server                       # uses inventory.db in CWD
./build/inventory-server --port 9876 --db /var/lib/inventory/data.db
```

The server reloads the file every time it restarts. On the very first run the
file is created automatically.

### Use the CLI

```bash
# Shorthand for the examples below
cli="./build/inventory-cli"
```

---

## Commands

### Servers

```bash
# Add a server
$cli add-server "web01" "192.168.1.10" "Rack A" "Primary web server"

# List all servers
$cli list-servers

# Edit a field (fields: name | hostname | location | description)
$cli edit-server 1 hostname "10.0.0.1"
$cli edit-server 1 description "Retired – do not use"
```

### Part types

```bash
# Add a part type
$cli add-part-type "RAM" "Memory modules"
$cli add-part-type "SSD" "Solid-state storage"

# List all part types
$cli list-part-types

# Edit a field (fields: name | description)
$cli edit-part-type 1 description "DDR4/DDR5 memory"
```

### Parts

```bash
# Add a part to a server
# add-part <server_id> <part_type_id> <name> <serial> <description>
$cli add-part 1 1 "16 GB DDR4" "SN-MEM-001" "DIMM slot A1"
$cli add-part 1 2 "Samsung 870 EVO 1 TB" "SN-SSD-004" "Primary OS drive"

# List parts of a server
$cli list-parts 1

# Edit a field (fields: name | serial | description | server_id | part_type_id)
$cli edit-part 2 serial "SN-SSD-005"
$cli edit-part 2 server_id 3
```

---

## Database file format

Plain text, one record per line – safe to inspect or diff with standard tools.

```
# device-inventory database
META|<next_server_id>|<next_part_type_id>|<next_part_id>
S|<id>|<name>|<hostname>|<location>|<description>
PT|<id>|<name>|<description>
P|<id>|<server_id>|<part_type_id>|<name>|<serial>|<description>
```

Pipe characters and backslashes inside field values are escaped with `\|`
and `\\` respectively.

---

## Wire protocol

Commands are newline-terminated lines; fields are separated by ASCII SOH
(`0x01`). Each connection carries exactly one request/response pair.

```
Client → Server:  COMMAND\x01arg1\x01arg2\n
Server → Client:  OK\n
                  field1\x01field2\x01...\n   ← 0 or more data rows
                  END\n
         -- or --
                  ERR <message>\n
```