Move telemetry configuration into YAML

README.md

@@ -22,10 +22,13 @@ TLS is not terminated or inspected. HTTPS remains end-to-end encrypted between t
 
 ```sh
 cargo build
+HERMES_CONFIG_PATH=examples/hermes.yaml cargo run
+
+# The CLI flag takes precedence over HERMES_CONFIG_PATH:
 cargo run -- --config examples/hermes.yaml
 ```
 
-The default configuration path is `hermes.yaml`. The included example listens on `127.0.0.1:8080` and allows only localhost clients.
+Configuration path precedence is `--config`, then `HERMES_CONFIG_PATH`, then `hermes.yaml`. This is the only environment variable read by Hermes; logging and OpenTelemetry are also configured in YAML. The included example listens on `127.0.0.1:8080` and allows only localhost clients.
 
 ```sh
 # Plain HTTP
@@ -42,6 +45,22 @@ listen_addr: "127.0.0.1:8080"
 connect_timeout_ms: 10000
 upstream_timeout_ms: 30000
 
+telemetry:
+  service_name: "hermes"
+  log_filter: "info"
+  resource_attributes:
+    deployment.environment.name: "development"
+  otlp:
+    endpoint: "http://127.0.0.1:4318"
+    timeout_ms: 10000
+    headers: {}
+    traces:
+      sample_ratio: 1.0
+    metrics:
+      export_interval_ms: 60000
+      temporality: "cumulative"
+    logs: {}
+
 acl:
   default_action: deny
 
@@ -68,13 +87,14 @@ acl:
 | `listen_addr` | `127.0.0.1:8080` | Downstream listen address |
 | `connect_timeout_ms` | `10000` | TCP connection timeout for `CONNECT` and the HTTP connector |
 | `upstream_timeout_ms` | `30000` | Time limit for receiving upstream HTTP response headers |
+| `telemetry` | see OpenTelemetry below | Logging, resource, and OTLP configuration |
 | `acl.default_action` | `deny` | Action when no rule matches |
 | `acl.users` | empty | Usernames and salted SHA-256 password hashes |
 | `acl.rules` | empty | Ordered ACL rules |
 
 Configuration is loaded and validated at startup. Unknown fields, invalid CIDRs or domain patterns, duplicate or empty rules, references to unknown users, and unsupported password hashes prevent startup. Restart Hermes to apply configuration changes.
 
-`RUST_LOG` controls log filtering and defaults to `info`, for example `RUST_LOG=hermes=debug`.
+`telemetry.log_filter` controls log filtering and defaults to `info`, for example `log_filter: "hermes=debug"`. `RUST_LOG` is not read.
 
 ### ACL rules
 
@@ -157,15 +177,29 @@ Password verification is synchronous and inexpensive, and digest comparisons are
 
 ## OpenTelemetry
 
-Hermes exports traces, metrics, and logs independently to an OpenTelemetry Collector using OTLP/HTTP (protobuf). Exporters use the standard OpenTelemetry environment variables.
+Hermes exports traces, metrics, and logs independently to an OpenTelemetry Collector using OTLP/HTTP (protobuf). All settings come from `telemetry` in YAML; `OTEL_*` environment variables are not read.
 
-```sh
-export OTEL_SERVICE_NAME=hermes
-export OTEL_EXPORTER_OTLP_ENDPOINT=http://127.0.0.1:4318
-cargo run -- --config examples/hermes.yaml
+```yaml
+telemetry:
+  service_name: "hermes"
+  log_filter: "info"
+  resource_attributes:
+    deployment.environment.name: "production"
+  otlp:
+    endpoint: "http://127.0.0.1:4318"
+    timeout_ms: 10000
+    headers: {}
+    traces:
+      sample_ratio: 1.0
+    metrics:
+      export_interval_ms: 60000
+      temporality: "cumulative"
+    logs: {}
 ```
 
-Signal-specific settings such as `OTEL_EXPORTER_OTLP_TRACES_ENDPOINT`, `OTEL_EXPORTER_OTLP_METRICS_ENDPOINT`, and `OTEL_EXPORTER_OTLP_LOGS_ENDPOINT` are also supported. Standard OTLP headers, timeouts, and trace sampling environment variables can be used.
+The common `otlp.endpoint` is a base URL; Hermes appends `/v1/traces`, `/v1/metrics`, and `/v1/logs`. Set `otlp.traces.endpoint`, `otlp.metrics.endpoint`, or `otlp.logs.endpoint` to override a signal with an exact full URL. OTLP headers may contain credentials, so protect the configuration file and never log its contents.
+
+Trace `sample_ratio` must be between 0 and 1. Metric `temporality` accepts `cumulative` or `delta`. Timeouts and export intervals must be greater than zero.
 
 Traces and logs are batched, metrics are exported periodically, and all providers are flushed during shutdown. An unavailable collector does not prevent the proxy from forwarding traffic, although exporter errors may appear in stdout logs.
 

examples/hermes.yaml

@@ -2,6 +2,23 @@ listen_addr: "127.0.0.1:8080"
 connect_timeout_ms: 10000
 upstream_timeout_ms: 30000
 
+telemetry:
+  service_name: "hermes"
+  log_filter: "info"
+  resource_attributes:
+    deployment.environment.name: "development"
+  otlp:
+    endpoint: "http://127.0.0.1:4318"
+    timeout_ms: 10000
+    headers: {}
+    traces:
+      # Set an endpoint here to override the common OTLP endpoint.
+      sample_ratio: 1.0
+    metrics:
+      export_interval_ms: 60000
+      temporality: "cumulative"
+    logs: {}
+
 acl:
   default_action: deny
   users: {}

src/config.rs

@@ -1,7 +1,9 @@
 use std::{collections::BTreeMap, fs, net::SocketAddr, path::Path, sync::Arc, time::Duration};
 
+use http::{HeaderName, HeaderValue, Uri};
 use serde::Deserialize;
 use thiserror::Error;
+use tracing_subscriber::EnvFilter;
 
 use crate::acl::{Acl, AclError};
 
@@ -13,6 +15,7 @@ pub struct Config {
     pub listen_addr: SocketAddr,
     pub connect_timeout: Duration,
     pub upstream_timeout: Duration,
+    pub telemetry: TelemetryConfig,
     pub(crate) acl: Arc<Acl>,
 }
 
@@ -34,11 +37,13 @@ impl Config {
         if file.upstream_timeout_ms == 0 {
             return Err(ConfigError::ZeroDuration("upstream_timeout_ms"));
         }
+        file.telemetry.validate()?;
 
         Ok(Self {
             listen_addr: file.listen_addr,
             connect_timeout: Duration::from_millis(file.connect_timeout_ms),
             upstream_timeout: Duration::from_millis(file.upstream_timeout_ms),
+            telemetry: file.telemetry,
             acl: Arc::new(Acl::from_config(file.acl)?),
         })
     }
@@ -53,6 +58,8 @@ struct FileConfig {
     connect_timeout_ms: u64,
     #[serde(default = "default_upstream_timeout_ms")]
     upstream_timeout_ms: u64,
+    #[serde(default)]
+    telemetry: TelemetryConfig,
     acl: AclConfig,
 }
 
@@ -68,6 +75,161 @@ const fn default_upstream_timeout_ms() -> u64 {
     DEFAULT_UPSTREAM_TIMEOUT_MS
 }
 
+#[derive(Clone, Deserialize)]
+#[serde(default, deny_unknown_fields)]
+pub struct TelemetryConfig {
+    pub(crate) service_name: String,
+    pub(crate) log_filter: String,
+    pub(crate) resource_attributes: BTreeMap<String, String>,
+    pub(crate) otlp: OtlpConfig,
+}
+
+impl Default for TelemetryConfig {
+    fn default() -> Self {
+        Self {
+            service_name: "hermes".to_owned(),
+            log_filter: "info".to_owned(),
+            resource_attributes: BTreeMap::new(),
+            otlp: OtlpConfig::default(),
+        }
+    }
+}
+
+impl TelemetryConfig {
+    fn validate(&self) -> Result<(), ConfigError> {
+        if self.service_name.trim().is_empty() {
+            return Err(ConfigError::EmptyServiceName);
+        }
+        EnvFilter::try_new(&self.log_filter)
+            .map_err(|error| ConfigError::InvalidLogFilter(error.to_string()))?;
+        validate_endpoint(&self.otlp.endpoint, "telemetry.otlp.endpoint")?;
+        validate_endpoint_override(&self.otlp.traces.endpoint, "telemetry.otlp.traces.endpoint")?;
+        validate_endpoint_override(
+            &self.otlp.metrics.endpoint,
+            "telemetry.otlp.metrics.endpoint",
+        )?;
+        validate_endpoint_override(&self.otlp.logs.endpoint, "telemetry.otlp.logs.endpoint")?;
+
+        if self.otlp.timeout_ms == 0 {
+            return Err(ConfigError::ZeroDuration("telemetry.otlp.timeout_ms"));
+        }
+        if self.otlp.metrics.export_interval_ms == 0 {
+            return Err(ConfigError::ZeroDuration(
+                "telemetry.otlp.metrics.export_interval_ms",
+            ));
+        }
+        if !self.otlp.traces.sample_ratio.is_finite()
+            || !(0.0..=1.0).contains(&self.otlp.traces.sample_ratio)
+        {
+            return Err(ConfigError::InvalidSampleRatio(
+                self.otlp.traces.sample_ratio,
+            ));
+        }
+
+        for (name, value) in &self.otlp.headers {
+            if HeaderName::from_bytes(name.as_bytes()).is_err()
+                || HeaderValue::from_str(value).is_err()
+            {
+                return Err(ConfigError::InvalidHeader(name.clone()));
+            }
+        }
+
+        Ok(())
+    }
+}
+
+fn validate_endpoint_override(
+    endpoint: &Option<String>,
+    field: &'static str,
+) -> Result<(), ConfigError> {
+    if let Some(endpoint) = endpoint {
+        validate_endpoint(endpoint, field)?;
+    }
+    Ok(())
+}
+
+fn validate_endpoint(endpoint: &str, field: &'static str) -> Result<(), ConfigError> {
+    let uri = endpoint
+        .parse::<Uri>()
+        .map_err(|_| ConfigError::InvalidEndpoint(field))?;
+    if !matches!(uri.scheme_str(), Some("http" | "https")) || uri.authority().is_none() {
+        return Err(ConfigError::InvalidEndpoint(field));
+    }
+    Ok(())
+}
+
+#[derive(Clone, Deserialize)]
+#[serde(default, deny_unknown_fields)]
+pub struct OtlpConfig {
+    pub(crate) endpoint: String,
+    pub(crate) timeout_ms: u64,
+    pub(crate) headers: BTreeMap<String, String>,
+    pub(crate) traces: TraceTelemetryConfig,
+    pub(crate) metrics: MetricTelemetryConfig,
+    pub(crate) logs: LogTelemetryConfig,
+}
+
+impl Default for OtlpConfig {
+    fn default() -> Self {
+        Self {
+            endpoint: "http://127.0.0.1:4318".to_owned(),
+            timeout_ms: 10_000,
+            headers: BTreeMap::new(),
+            traces: TraceTelemetryConfig::default(),
+            metrics: MetricTelemetryConfig::default(),
+            logs: LogTelemetryConfig::default(),
+        }
+    }
+}
+
+#[derive(Clone, Deserialize)]
+#[serde(default, deny_unknown_fields)]
+pub(crate) struct TraceTelemetryConfig {
+    pub endpoint: Option<String>,
+    pub sample_ratio: f64,
+}
+
+impl Default for TraceTelemetryConfig {
+    fn default() -> Self {
+        Self {
+            endpoint: None,
+            sample_ratio: 1.0,
+        }
+    }
+}
+
+#[derive(Clone, Deserialize)]
+#[serde(default, deny_unknown_fields)]
+pub(crate) struct MetricTelemetryConfig {
+    pub endpoint: Option<String>,
+    pub export_interval_ms: u64,
+    pub temporality: MetricTemporality,
+}
+
+impl Default for MetricTelemetryConfig {
+    fn default() -> Self {
+        Self {
+            endpoint: None,
+            export_interval_ms: 60_000,
+            temporality: MetricTemporality::Cumulative,
+        }
+    }
+}
+
+#[derive(Clone, Default, Deserialize)]
+#[serde(default, deny_unknown_fields)]
+pub(crate) struct LogTelemetryConfig {
+    pub endpoint: Option<String>,
+}
+
+#[derive(Clone, Copy, Debug, Default, Deserialize, Eq, PartialEq)]
+#[serde(rename_all = "lowercase")]
+pub(crate) enum MetricTemporality {
+    #[default]
+    Cumulative,
+    Delta,
+}
+
 #[derive(Deserialize)]
 #[serde(deny_unknown_fields)]
 pub(crate) struct AclConfig {
@@ -118,6 +280,16 @@ pub enum ConfigError {
     Yaml(#[from] serde_norway::Error),
     #[error("{0} must be greater than zero")]
     ZeroDuration(&'static str),
+    #[error("{0} must be an absolute http:// or https:// endpoint")]
+    InvalidEndpoint(&'static str),
+    #[error("telemetry.otlp.traces.sample_ratio must be between 0 and 1, got {0}")]
+    InvalidSampleRatio(f64),
+    #[error("invalid telemetry.log_filter: {0}")]
+    InvalidLogFilter(String),
+    #[error("invalid OTLP header {0:?}")]
+    InvalidHeader(String),
+    #[error("telemetry.service_name must not be empty")]
+    EmptyServiceName,
     #[error(transparent)]
     Acl(#[from] AclError),
 }
@@ -142,6 +314,108 @@ acl:
         assert_eq!(config.listen_addr, default_listen_addr());
         assert_eq!(config.connect_timeout, Duration::from_secs(10));
         assert_eq!(config.upstream_timeout, Duration::from_secs(30));
+        assert_eq!(config.telemetry.service_name, "hermes");
+        assert_eq!(config.telemetry.log_filter, "info");
+        assert_eq!(config.telemetry.otlp.endpoint, "http://127.0.0.1:4318");
+        assert_eq!(config.telemetry.otlp.traces.sample_ratio, 1.0);
+        assert_eq!(
+            config.telemetry.otlp.metrics.temporality,
+            MetricTemporality::Cumulative
+        );
+    }
+
+    #[test]
+    fn loads_telemetry_configuration() {
+        let config = Config::from_yaml(
+            r#"
+telemetry:
+  service_name: "hermes-test"
+  log_filter: "hermes=debug"
+  resource_attributes:
+    deployment.environment.name: "test"
+  otlp:
+    endpoint: "https://collector.example:4318"
+    timeout_ms: 5000
+    headers:
+      Authorization: "Bearer secret"
+    traces:
+      endpoint: "https://traces.example:4318"
+      sample_ratio: 0.25
+    metrics:
+      export_interval_ms: 1000
+      temporality: "delta"
+    logs:
+      endpoint: "https://logs.example:4318"
+acl: {}
+"#,
+        )
+        .unwrap();
+
+        assert_eq!(config.telemetry.service_name, "hermes-test");
+        assert_eq!(config.telemetry.log_filter, "hermes=debug");
+        assert_eq!(
+            config.telemetry.resource_attributes["deployment.environment.name"],
+            "test"
+        );
+        assert_eq!(config.telemetry.otlp.timeout_ms, 5000);
+        assert_eq!(
+            config.telemetry.otlp.headers["Authorization"],
+            "Bearer secret"
+        );
+        assert_eq!(
+            config.telemetry.otlp.traces.endpoint.as_deref(),
+            Some("https://traces.example:4318")
+        );
+        assert_eq!(config.telemetry.otlp.traces.sample_ratio, 0.25);
+        assert_eq!(config.telemetry.otlp.metrics.export_interval_ms, 1000);
+        assert_eq!(
+            config.telemetry.otlp.metrics.temporality,
+            MetricTemporality::Delta
+        );
+        assert_eq!(
+            config.telemetry.otlp.logs.endpoint.as_deref(),
+            Some("https://logs.example:4318")
+        );
+    }
+
+    #[test]
+    fn rejects_invalid_telemetry_configuration() {
+        for yaml in [
+            "telemetry:\n  otlp:\n    endpoint: \"collector:4318\"\nacl: {}\n",
+            "telemetry:\n  otlp:\n    endpoint: \"ftp://collector.example\"\nacl: {}\n",
+            "telemetry:\n  otlp:\n    traces:\n      endpoint: \"not-a-url\"\nacl: {}\n",
+        ] {
+            assert!(matches!(
+                Config::from_yaml(yaml),
+                Err(ConfigError::InvalidEndpoint(_))
+            ));
+        }
+
+        for yaml in [
+            "telemetry:\n  otlp:\n    timeout_ms: 0\nacl: {}\n",
+            "telemetry:\n  otlp:\n    metrics:\n      export_interval_ms: 0\nacl: {}\n",
+        ] {
+            assert!(matches!(
+                Config::from_yaml(yaml),
+                Err(ConfigError::ZeroDuration(_))
+            ));
+        }
+
+        let ratio = Config::from_yaml(
+            "telemetry:\n  otlp:\n    traces:\n      sample_ratio: 1.1\nacl: {}\n",
+        );
+        assert!(matches!(ratio, Err(ConfigError::InvalidSampleRatio(_))));
+
+        let filter = Config::from_yaml("telemetry:\n  log_filter: \"hermes=verbose\"\nacl: {}\n");
+        assert!(matches!(filter, Err(ConfigError::InvalidLogFilter(_))));
+
+        let header = Config::from_yaml(
+            "telemetry:\n  otlp:\n    headers:\n      Authorization: \"bad\\nvalue\"\nacl: {}\n",
+        );
+        assert!(matches!(header, Err(ConfigError::InvalidHeader(_))));
+
+        let service = Config::from_yaml("telemetry:\n  service_name: \"\"\nacl: {}\n");
+        assert!(matches!(service, Err(ConfigError::EmptyServiceName)));
     }
 
     #[test]

src/main.rs

@@ -1,4 +1,4 @@
-use std::path::PathBuf;
+use std::{env, path::PathBuf};
 
 use clap::{Parser, Subcommand};
 use hermes::{BoxError, acl, config::Config, telemetry};
@@ -10,8 +10,13 @@ use zeroize::Zeroizing;
     about = "A minimal HTTP forward proxy with OpenTelemetry observability"
 )]
 struct Cli {
-    #[arg(short, long, default_value = "hermes.yaml", value_name = "PATH")]
-    config: PathBuf,
+    #[arg(
+        short,
+        long,
+        value_name = "PATH",
+        help = "Configuration file path (overrides HERMES_CONFIG_PATH)"
+    )]
+    config: Option<PathBuf>,
     #[command(subcommand)]
     command: Option<Command>,
 }
@@ -35,12 +40,13 @@ async fn main() -> Result<(), BoxError> {
         return Ok(());
     }
 
-    let telemetry = telemetry::init()?;
-    let result: Result<(), BoxError> = async {
-        let config = Config::load(&cli.config)?;
-        hermes::run(config).await
-    }
-    .await;
+    let config_path = cli
+        .config
+        .or_else(|| env::var_os("HERMES_CONFIG_PATH").map(PathBuf::from))
+        .unwrap_or_else(|| PathBuf::from("hermes.yaml"));
+    let config = Config::load(config_path)?;
+    let telemetry = telemetry::init(&config.telemetry)?;
+    let result = hermes::run(config).await;
 
     telemetry.shutdown();
     result

src/proxy.rs

@@ -617,7 +617,7 @@ mod tests {
     };
 
     use super::*;
-    use crate::config::{AclConfig, Action, RuleConfig, UserConfig};
+    use crate::config::{AclConfig, Action, RuleConfig, TelemetryConfig, UserConfig};
 
     #[test]
     fn validates_absolute_http_targets() {
@@ -871,6 +871,7 @@ mod tests {
             listen_addr: address,
             connect_timeout: Duration::from_secs(2),
             upstream_timeout: Duration::from_secs(2),
+            telemetry: TelemetryConfig::default(),
             acl: Arc::new(acl),
         });
         let task = tokio::spawn(async move {

src/telemetry.rs

@@ -1,19 +1,30 @@
-use std::env;
+use std::{collections::HashMap, time::Duration};
 
 use http::{HeaderMap, HeaderName, HeaderValue, header};
 use opentelemetry::{
-    global,
+    KeyValue, global,
     propagation::{Extractor, Injector},
 };
 use opentelemetry_appender_tracing::layer::OpenTelemetryTracingBridge;
-use opentelemetry_otlp::{LogExporter, MetricExporter, Protocol, SpanExporter, WithExportConfig};
+use opentelemetry_otlp::{
+    LogExporter, MetricExporter, Protocol, SpanExporter, WithExportConfig, WithHttpConfig,
+};
 use opentelemetry_sdk::{
-    Resource, logs::SdkLoggerProvider, metrics::SdkMeterProvider,
-    propagation::TraceContextPropagator, trace::SdkTracerProvider,
+    Resource,
+    logs::{BatchConfigBuilder as LogBatchConfigBuilder, BatchLogProcessor, SdkLoggerProvider},
+    metrics::{PeriodicReader, SdkMeterProvider, Temporality},
+    propagation::TraceContextPropagator,
+    trace::{
+        BatchConfigBuilder as TraceBatchConfigBuilder, BatchSpanProcessor, Sampler,
+        SdkTracerProvider,
+    },
 };
 use tracing_subscriber::{EnvFilter, Layer, layer::SubscriberExt, util::SubscriberInitExt};
 
-use crate::BoxError;
+use crate::{
+    BoxError,
+    config::{MetricTemporality, OtlpConfig, TelemetryConfig},
+};
 
 pub struct TelemetryGuard {
     tracer_provider: SdkTracerProvider,
@@ -35,18 +46,43 @@ impl TelemetryGuard {
     }
 }
 
-pub fn init() -> Result<TelemetryGuard, BoxError> {
+pub fn init(config: &TelemetryConfig) -> Result<TelemetryGuard, BoxError> {
     global::set_text_map_propagator(TraceContextPropagator::new());
 
-    let service_name = env::var("OTEL_SERVICE_NAME").unwrap_or_else(|_| "hermes".to_owned());
-    let resource = Resource::builder().with_service_name(service_name).build();
+    let resource = Resource::builder_empty()
+        .with_service_name(config.service_name.clone())
+        .with_attributes(
+            config
+                .resource_attributes
+                .iter()
+                .map(|(key, value)| KeyValue::new(key.clone(), value.clone())),
+        )
+        .build();
+    let timeout = Duration::from_millis(config.otlp.timeout_ms);
+    let headers = otlp_headers(&config.otlp);
 
     let metric_exporter = MetricExporter::builder()
         .with_http()
         .with_protocol(Protocol::HttpBinary)
+        .with_endpoint(endpoint(
+            &config.otlp,
+            &config.otlp.metrics.endpoint,
+            "metrics",
+        ))
+        .with_timeout(timeout)
+        .with_headers(headers.clone())
+        .with_temporality(match config.otlp.metrics.temporality {
+            MetricTemporality::Cumulative => Temporality::Cumulative,
+            MetricTemporality::Delta => Temporality::Delta,
+        })
         .build()?;
+    let metric_reader = PeriodicReader::builder(metric_exporter)
+        .with_interval(Duration::from_millis(
+            config.otlp.metrics.export_interval_ms,
+        ))
+        .build();
     let meter_provider = SdkMeterProvider::builder()
-        .with_periodic_exporter(metric_exporter)
+        .with_reader(metric_reader)
         .with_resource(resource.clone())
         .build();
     global::set_meter_provider(meter_provider.clone());
@@ -54,24 +90,55 @@ pub fn init() -> Result<TelemetryGuard, BoxError> {
     let log_exporter = LogExporter::builder()
         .with_http()
         .with_protocol(Protocol::HttpBinary)
+        .with_endpoint(endpoint(&config.otlp, &config.otlp.logs.endpoint, "logs"))
+        .with_timeout(timeout)
+        .with_headers(headers.clone())
         .build()?;
+    let log_processor = BatchLogProcessor::builder(log_exporter)
+        .with_batch_config(
+            LogBatchConfigBuilder::default()
+                .with_max_queue_size(2048)
+                .with_scheduled_delay(Duration::from_secs(1))
+                .with_max_export_batch_size(512)
+                .build(),
+        )
+        .build();
     let logger_provider = SdkLoggerProvider::builder()
-        .with_batch_exporter(log_exporter)
+        .with_log_processor(log_processor)
         .with_resource(resource.clone())
         .build();
 
     let span_exporter = SpanExporter::builder()
         .with_http()
         .with_protocol(Protocol::HttpBinary)
+        .with_endpoint(endpoint(
+            &config.otlp,
+            &config.otlp.traces.endpoint,
+            "traces",
+        ))
+        .with_timeout(timeout)
+        .with_headers(headers)
         .build()?;
+    let span_processor = BatchSpanProcessor::builder(span_exporter)
+        .with_batch_config(
+            TraceBatchConfigBuilder::default()
+                .with_max_queue_size(2048)
+                .with_scheduled_delay(Duration::from_secs(5))
+                .with_max_export_batch_size(512)
+                .build(),
+        )
+        .build();
     let tracer_provider = SdkTracerProvider::builder()
-        .with_batch_exporter(span_exporter)
+        .with_span_processor(span_processor)
+        .with_sampler(Sampler::ParentBased(Box::new(Sampler::TraceIdRatioBased(
+            config.otlp.traces.sample_ratio,
+        ))))
         .with_resource(resource)
         .build();
     global::set_tracer_provider(tracer_provider.clone());
 
-    let fmt_filter = env_filter();
-    let otel_log_filter = exporter_log_filter(env_filter());
+    let fmt_filter = EnvFilter::try_new(&config.log_filter)?;
+    let otel_log_filter = exporter_log_filter(EnvFilter::try_new(&config.log_filter)?);
     let tracer = global::tracer("hermes");
 
     tracing_subscriber::registry()
@@ -87,8 +154,18 @@ pub fn init() -> Result<TelemetryGuard, BoxError> {
     })
 }
 
-fn env_filter() -> EnvFilter {
-    EnvFilter::try_from_default_env().unwrap_or_else(|_| EnvFilter::new("info"))
+fn endpoint(config: &OtlpConfig, override_endpoint: &Option<String>, signal: &str) -> String {
+    override_endpoint
+        .clone()
+        .unwrap_or_else(|| format!("{}/v1/{signal}", config.endpoint.trim_end_matches('/')))
+}
+
+fn otlp_headers(config: &OtlpConfig) -> HashMap<String, String> {
+    config
+        .headers
+        .iter()
+        .map(|(key, value)| (key.clone(), value.clone()))
+        .collect()
 }
 
 fn exporter_log_filter(filter: EnvFilter) -> EnvFilter {
@@ -177,4 +254,28 @@ mod tests {
         assert!(!headers.contains_key("proxy-authorization"));
         assert_eq!(headers["x-keep"], "value");
     }
+
+    #[test]
+    fn signal_endpoints_inherit_the_common_endpoint() {
+        let config = OtlpConfig::default();
+        assert_eq!(
+            endpoint(&config, &None, "traces"),
+            "http://127.0.0.1:4318/v1/traces"
+        );
+        assert_eq!(
+            endpoint(
+                &config,
+                &Some("http://signals.example:4318/custom/traces".to_owned()),
+                "traces",
+            ),
+            "http://signals.example:4318/custom/traces"
+        );
+
+        let mut with_slash = OtlpConfig::default();
+        with_slash.endpoint.push('/');
+        assert_eq!(
+            endpoint(&with_slash, &None, "metrics"),
+            "http://127.0.0.1:4318/v1/metrics"
+        );
+    }
 }