Refactor packages

[josecelano]

From: #255 (comment)

These are the packages we have extracted so far:

./packages/
├── clock
├── configuration
├── located-error
├── primitives
├── test-helpers
└── torrent-repository

In the long-term I see we could have the following:

packages/
├── api             <- NEW!: torrust-tracker-api (servers)
├── udp             <- NEW!: torrust-tracker-udp (servers)
├── http            <- NEW!: torrust-tracker-http (servers)
├── core            <- NEW!: torrust-tracker-core (tracker)
├── bittorrent      <- NEW!: torrust-bittorrent (shared)
├── clock           <-       torrust-clock (shared)
├── crypto          <- NEW!: torrust-crypto (shared)
├── configuration   <-       torrust-tracker-configuration
├── located-error   <-       torrust-tracker-located-error
├── primitives      <-       torrust-tracker-primitives
└── test-helpers    <-       torrust-tracker-test-helpers

The "shared" ones could be a single package, but as they do not have much in common and could be used independently, I would keep them in separate packages.

I would also refactor the config file from:

log_level = "debug"
mode = "public"
db_driver = "Sqlite3"
db_path = "./storage/database/data.db"
announce_interval = 120
min_announce_interval = 120
max_peer_timeout = 900
on_reverse_proxy = false
external_ip = "2.137.87.41"
tracker_usage_statistics = true
persistent_torrent_completed_stat = true
inactive_peer_cleanup_interval = 600
remove_peerless_torrents = false

[[udp_trackers]]
enabled = true
bind_address = "0.0.0.0:6969"

[[http_trackers]]
enabled = true
bind_address = "0.0.0.0:7070"
ssl_enabled = false
ssl_cert_path = "./storage/ssl_certificates/localhost.crt"
ssl_key_path = "./storage/ssl_certificates/localhost.key"

[http_api]
enabled = true
bind_address = "0.0.0.0:1212"
ssl_enabled = false
ssl_cert_path = "./storage/ssl_certificates/localhost.crt"
ssl_key_path = "./storage/ssl_certificates/localhost.key"

[http_api.access_tokens]
admin = "MyAccessToken"

to:

log_level = "debug"

[core_tracker]
mode = "public"
db_driver = "Sqlite3"
db_path = "./storage/database/data.db"
announce_interval = 120
min_announce_interval = 120
max_peer_timeout = 900
on_reverse_proxy = false
external_ip = "2.137.87.41"
tracker_usage_statistics = true
persistent_torrent_completed_stat = true
inactive_peer_cleanup_interval = 600
remove_peerless_torrents = false

[[udp_trackers]]
enabled = true
bind_address = "0.0.0.0:6969"

[[http_trackers]]
enabled = true
bind_address = "0.0.0.0:7070"
ssl_enabled = false
ssl_cert_path = "./storage/ssl_certificates/localhost.crt"
ssl_key_path = "./storage/ssl_certificates/localhost.key"

[http_api]
enabled = true
bind_address = "0.0.0.0:1212"
ssl_enabled = false
ssl_cert_path = "./storage/ssl_certificates/localhost.crt"
ssl_key_path = "./storage/ssl_certificates/localhost.key"

[http_api.access_tokens]
admin = "MyAccessToken"

The configuration will also change accordingly from:

pub struct Configuration {
    pub log_level: Option<String>,
    pub mode: TrackerMode,
    pub db_driver: DatabaseDriver,
    pub db_path: String,
    pub announce_interval: u32,
    pub min_announce_interval: u32,
    pub max_peer_timeout: u32,
    pub on_reverse_proxy: bool,
    pub external_ip: Option<String>,
    pub tracker_usage_statistics: bool,
    pub persistent_torrent_completed_stat: bool,
    pub inactive_peer_cleanup_interval: u64,
    pub remove_peerless_torrents: bool,
    pub udp_trackers: Vec<UdpTracker>,
    pub http_trackers: Vec<HttpTracker>,
    pub http_api: HttpApi,
}

to:

pub struct Configuration {
    pub log_level: Option<String>,
    pub core_tracker: CoreTracker,
    pub udp_trackers: Vec<UdpTracker>,
    pub http_trackers: Vec<HttpTracker>,
    pub http_api: HttpApi,
}

pub struct CoreTracker {
    pub mode: TrackerMode,
    pub db_driver: DatabaseDriver,
    pub db_path: String,
    pub announce_interval: u32,
    pub min_announce_interval: u32,
    pub max_peer_timeout: u32,
    pub on_reverse_proxy: bool,
    pub external_ip: Option<String>,
    pub tracker_usage_statistics: bool,
    pub persistent_torrent_completed_stat: bool,
    pub inactive_peer_cleanup_interval: u64,
    pub remove_peerless_torrents: bool,
}

I'm tempted to do those refactorings before continuing with the crate's documentation.

I would also move UdpTracker, HttpTracker and HttpApi to their crates (if possible) or even to new packages if we depend only on those types:

packages/
├── api             <- NEW!: torrust-tracker-api (servers)
├── udp             <- NEW!: torrust-tracker-udp (servers)
├── http            <- NEW!: torrust-tracker-http (servers)
├── api-config      <- NEW!: torrust-tracker-api-config
├── udp-config      <- NEW!: torrust-tracker-udp-config
├── http-config     <- NEW!: torrust-tracker-http-config
├── core-config     <- NEW!: torrust-tracker-core-config
...

I would keep the current torrust-tracker-configuration for the main tracker app configuration:

pub struct Configuration {
    pub log_level: Option<String>,
    pub core_tracker: CoreTracker,
    pub udp_trackers: Vec<UdpTracker>,
    pub http_trackers: Vec<HttpTracker>,
    pub http_api: HttpApi,
}

What do you think @da2ce7 @WarmBeer? We can do it later, but it will cost extra effort to refactor the documentation.

Regarding the config file, that would be a big change that would need to wait until the next major release (V4) if we want to do it.

Originally posted by @josecelano in #255 (comment)