Struct ServerConfig 

pub struct ServerConfig {

    pub domain: String,
    pub postmaster: String,
    pub smtp: SmtpServerConfig,
    pub imap: Option<ImapServerConfig>,
    pub jmap: Option<JmapServerConfig>,
    pub pop3: Option<Pop3ServerConfig>,
    pub storage: StorageConfig,
    pub processors: Vec<ProcessorConfig>,
    pub runtime_dir: String,
    pub relay: Option<RelayConfig>,
    pub auth: Option<AuthConfig>,
    pub logging: Option<LoggingConfig>,
    pub queue: Option<QueueConfig>,
    pub security: Option<SecurityConfig>,
    pub domains: Option<DomainsConfig>,
    pub metrics: Option<MetricsConfig>,
    pub tracing: Option<TracingConfig>,
    pub connection_limits: Option<ConnectionLimitsConfig>,
    pub performance: PerformanceConfig,
    pub tls: Option<TlsConfig>,
    pub chroot: bool,
    pub run_as_user: String,
    pub run_as_group: String,
    pub extra: Vec<String>,
}

Main server configuration.

Loaded from a TOML or YAML file via ServerConfig::from_file. All optional sections default to None; required fields (domain, postmaster, smtp, storage, processors) must be present.

Fields

domain: String

Required. Primary mail domain served by this RusMES installation (e.g. "mail.example.com"). Must be a syntactically valid domain name.

postmaster: String

Required. RFC 5321 postmaster email address (e.g. "postmaster@example.com"). Used as the envelope sender for system-generated bounce messages.

smtp: SmtpServerConfig

Required. SMTP listener configuration (host, port, TLS port, size limits).

imap: Option<ImapServerConfig>

Default: None. IMAP4rev1 listener configuration. When absent the IMAP service is not started.

jmap: Option<JmapServerConfig>

Default: None. JMAP HTTP listener configuration. When absent the JMAP service is not started.

pop3: Option<Pop3ServerConfig>

Default: None. POP3 listener configuration. When absent the POP3 service is not started.

storage: StorageConfig

Required. Mail storage backend (filesystem, PostgreSQL, or AmateRS).

processors: Vec<ProcessorConfig>

Required. Ordered list of processor chains. At least one processor named "root" must be present.

runtime_dir: String

Default: "/var/run/rusmes". Per-process runtime directory used for the PID file, the rate-limiter snapshot, and any other ephemeral state files. Must be writable by the user running rusmes-server.

relay: Option<RelayConfig>

Default: None. Outbound SMTP relay configuration. When absent, rusmes delivers directly via DNS MX lookup.

auth: Option<AuthConfig>

Default: None. Authentication backend configuration (file, LDAP, SQL, or OAuth2). When absent the server falls back to no-auth mode.

logging: Option<LoggingConfig>

Default: None. Logging configuration (level, format, output, file rotation). When absent the server logs info-level messages to stdout in text format.

queue: Option<QueueConfig>

Default: None. Outbound queue configuration (retry delays, back-off). When absent, reasonable built-in defaults are used.

security: Option<SecurityConfig>

Default: None. Security configuration (relay networks, blocked IPs, recipient validation). When absent all security checks are disabled.

domains: Option<DomainsConfig>

Default: None. Local domain and alias mapping configuration. When absent only the primary domain is considered local.

metrics: Option<MetricsConfig>

Default: None. Prometheus metrics endpoint configuration. When absent the /metrics endpoint is not exposed.

tracing: Option<TracingConfig>

Default: None. OpenTelemetry OTLP tracing configuration. When absent distributed tracing is disabled.

connection_limits: Option<ConnectionLimitsConfig>

Default: None. Per-IP and global connection limit configuration. When absent no connection caps are enforced.

performance: PerformanceConfig

Default: PerformanceConfig::default(). Runtime performance tuning: Tokio worker threads, connection pool sizes, and per-connection buffer sizes. Omitting [performance] uses conservative built-in defaults.

tls: Option<TlsConfig>

Default: None. TLS certificate and key paths. Supports a shared [tls.default] endpoint and optional per-protocol overrides ([tls.smtp], [tls.imap], [tls.pop3], [tls.jmap]).

chroot: bool

Default: false. When true, call chroot(runtime_dir) after binding all sockets and loading TLS material, before dropping privileges. Has effect only on Linux; on other platforms a tracing::warn! is emitted and this field is otherwise ignored.

run_as_user: String

Default: "" (no-op). System user name to setuid to after binding all sockets. The empty string means “do not change UID”. Only effective on Linux; ignored on other platforms (with a warning).

run_as_group: String

Default: "" (no-op). System group name to setgid to after binding all sockets. The empty string means “do not change GID”. Only effective on Linux; ignored on other platforms (with a warning).

extra: Vec<String>

Unknown TOML/YAML keys captured for diagnostic warnings.

Not serialized to output. Populated by ServerConfig::from_file via a two-phase parse (raw toml::Value → known-key diff) so that warn_unknown_keys can emit tracing::warn! for each entry. Exposed as pub so tests can assert on which keys were captured without relying on subscriber interception.

Implementations

impl ServerConfig

pub fn apply_env_overrides(&mut self)

Apply environment variable overrides to configuration.

Environment variables follow the convention RUSMES_SECTION_KEY. Priority: env vars > config file > defaults.

Supported environment variables:

• RUSMES_DOMAIN
• RUSMES_POSTMASTER
• RUSMES_SMTP_HOST
• RUSMES_SMTP_PORT
• RUSMES_SMTP_TLS_PORT
• RUSMES_SMTP_MAX_MESSAGE_SIZE
• RUSMES_SMTP_REQUIRE_AUTH
• RUSMES_SMTP_ENABLE_STARTTLS
• RUSMES_SMTP_RATE_LIMIT_MAX_CONNECTIONS_PER_IP
• RUSMES_SMTP_RATE_LIMIT_MAX_MESSAGES_PER_HOUR
• RUSMES_SMTP_RATE_LIMIT_WINDOW_DURATION
• RUSMES_IMAP_HOST
• RUSMES_IMAP_PORT
• RUSMES_IMAP_TLS_PORT
• RUSMES_JMAP_HOST
• RUSMES_JMAP_PORT
• RUSMES_JMAP_BASE_URL
• RUSMES_STORAGE_PATH (for filesystem backend)
• RUSMES_LOG_LEVEL
• RUSMES_LOG_FORMAT
• RUSMES_LOG_OUTPUT
• RUSMES_QUEUE_INITIAL_DELAY
• RUSMES_QUEUE_MAX_DELAY
• RUSMES_QUEUE_BACKOFF_MULTIPLIER
• RUSMES_QUEUE_MAX_ATTEMPTS
• RUSMES_QUEUE_WORKER_THREADS
• RUSMES_QUEUE_BATCH_SIZE
• RUSMES_METRICS_ENABLED
• RUSMES_METRICS_BIND_ADDRESS
• RUSMES_METRICS_PATH
• RUSMES_TRACING_ENABLED
• RUSMES_TRACING_ENDPOINT
• RUSMES_TRACING_PROTOCOL (grpc or http)
• RUSMES_TRACING_SERVICE_NAME
• RUSMES_TRACING_SAMPLE_RATIO
• RUSMES_CONNECTION_LIMITS_MAX_CONNECTIONS_PER_IP
• RUSMES_CONNECTION_LIMITS_MAX_TOTAL_CONNECTIONS
• RUSMES_CONNECTION_LIMITS_IDLE_TIMEOUT
• RUSMES_CONNECTION_LIMITS_REAPER_INTERVAL

impl ServerConfig

pub fn from_file(path: impl AsRef<Path>) -> Result<Self>

Load configuration from a TOML or YAML file.

The format is auto-detected based on file extension:

• .toml files are parsed as TOML
• .yaml or .yml files are parsed as YAML

pub fn validate(&self) -> Result<()>

Validate the entire configuration.

This method is called automatically when loading configuration from a file. It validates:

• Domain name format
• Postmaster email address
• Port numbers for SMTP, IMAP, JMAP
• Storage path accessibility
• Processor uniqueness
• Local domain names (if configured)

pub fn postmaster_address(&self) -> Result<MailAddress>

Get postmaster address.

pub fn tls_for_protocol( &self, proto: ProtocolKind, ) -> Option<&TlsEndpointConfig>

Return the TlsEndpointConfig for proto, or None if no TLS is configured.

Delegates to TlsConfig::tls_for_protocol which returns the per-protocol override when present and falls back to tls.default.

pub fn warn_unknown_keys(&self)

Emit tracing::warn! for every unknown top-level configuration key.

Called automatically by ServerConfig::from_file after deserialization. Operators can use the warnings to detect typos or stale keys without causing a hard failure.

Trait Implementations

impl Clone for ServerConfig

fn clone(&self) -> ServerConfig

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ServerConfig

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for ServerConfig

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for ServerConfig

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.