feat: add otlp endpoint flag

Signed-off-by: Fabrizio Sestito <fabrizio.sestito@suse.com>

Author: fabriziosestito

src/cli.rs

@@ -169,7 +169,12 @@ pub(crate) fn build_cli() -> Command {
                 .long("continue-on-errors")
                 .env("KUBEWARDEN_CONTINUE_ON_ERRORS")
                 .action(ArgAction::SetTrue)
-                .hide(true)
+                .hide(true),
+            Arg::new("otlp-endpoint")
+                .long("otlp-endpoint")
+                .env("OTEL_EXPORTER_OTLP_ENDPOINT")
+                .default_value("http://localhost:4317")
+                .help("The OTLP gRPC endpoint for exporting traces and metrics.")
     ];
     args.sort_by(|a, b| a.get_id().cmp(b.get_id()));
 

src/config.rs

@@ -41,6 +41,7 @@ pub struct Config {
     pub log_level: String,
     pub log_fmt: String,
     pub log_no_color: bool,
+    pub otlp_endpoint: Option<String>,
     pub daemon: bool,
     pub enable_pprof: bool,
     pub daemon_pid_file: String,
@@ -125,6 +126,9 @@ impl Config {
             .get_one::<bool>("log-no-color")
             .expect("clap should have assigned a default value")
             .to_owned();
+
+        let otlp_endpoint = matches.get_one::<String>("otlp-endpoint").cloned();
+
         let (cert_file, key_file) = tls_files(matches)?;
         let tls_config = if cert_file.is_empty() {
             None
@@ -160,6 +164,7 @@ impl Config {
             log_level,
             log_fmt,
             log_no_color,
+            otlp_endpoint,
             daemon,
             daemon_pid_file,
             daemon_stdout_file,

src/main.rs

@@ -21,10 +21,15 @@ async fn main() -> Result<()> {
     let matches = cli::build_cli().get_matches();
     let config = policy_server::config::Config::from_args(&matches)?;
 
-    setup_tracing(&config.log_level, &config.log_fmt, config.log_no_color)?;
+    setup_tracing(
+        &config.log_level,
+        &config.log_fmt,
+        config.log_no_color,
+        config.otlp_endpoint.as_deref(),
+    )?;
 
     if config.metrics_enabled {
-        setup_metrics()?;
+        setup_metrics(config.otlp_endpoint.as_deref())?;
     };
 
     if config.daemon {

src/metrics.rs

@@ -10,18 +10,20 @@ pub use policy_evaluations_latency::record_policy_latency;
 
 const METER_NAME: &str = "kubewarden";
 
-pub fn setup_metrics() -> Result<()> {
-    let meter_reader = opentelemetry_sdk::metrics::PeriodicReader::builder(
-        opentelemetry_otlp::MetricExporter::builder()
-            .with_tonic()
-            .with_export_config(ExportConfig::default())
-            .build()?,
-        runtime::Tokio,
-    )
-    .build();
+pub fn setup_metrics(otlp_endpoint: Option<&str>) -> Result<()> {
+    let mut metric_exporter_builder = opentelemetry_otlp::MetricExporter::builder()
+        .with_tonic()
+        .with_export_config(ExportConfig::default());
+    if let Some(endpoint) = otlp_endpoint {
+        metric_exporter_builder = metric_exporter_builder.with_endpoint(endpoint);
+    }
+    let meter_reader = metric_exporter_builder.build()?;
+    let periodic_reader =
+        opentelemetry_sdk::metrics::PeriodicReader::builder(meter_reader, runtime::Tokio).build();
     let meter_provider = opentelemetry_sdk::metrics::SdkMeterProvider::builder()
-        .with_reader(meter_reader)
+        .with_reader(periodic_reader)
         .build();
+
     global::set_meter_provider(meter_provider);
     Ok(())
 }

src/tracing.rs

@@ -1,13 +1,19 @@
 use anyhow::{anyhow, Result};
 use opentelemetry::trace::TracerProvider;
+use opentelemetry_otlp::WithExportConfig;
 use tracing_subscriber::prelude::*;
 use tracing_subscriber::{fmt, EnvFilter};
 
 use crate::config;
 
 // Setup the tracing system. This MUST be done inside of a tokio Runtime
 // because some collectors rely on it and would panic otherwise.
-pub fn setup_tracing(log_level: &str, log_fmt: &str, log_no_color: bool) -> Result<()> {
+pub fn setup_tracing(
+    log_level: &str,
+    log_fmt: &str,
+    log_no_color: bool,
+    otlp_endpoint: Option<&str>,
+) -> Result<()> {
     // setup logging
     let filter_layer = EnvFilter::new(log_level)
         // some of our dependencies generate trace events too, but we don't care about them ->
@@ -37,11 +43,16 @@ pub fn setup_tracing(log_level: &str, log_fmt: &str, log_no_color: bool) -> Resu
         "otlp" => {
             // Create a new OpenTelemetry pipeline sending events to a
             // OpenTelemetry collector using the OTLP format.
-            // The collector must run on localhost (eg: use a sidecar inside of k8s)
-            // using GRPC
-            let otlp_exporter = opentelemetry_otlp::SpanExporter::builder()
-                .with_tonic()
-                .build()?;
+            // If no endpoint is provided, the default one is used.
+            // The default endpoint is "http://localhost:4317".
+            let mut otlp_exporter_builder =
+                opentelemetry_otlp::SpanExporter::builder().with_tonic();
+
+            if let Some(endpoint) = otlp_endpoint {
+                otlp_exporter_builder = otlp_exporter_builder.with_endpoint(endpoint);
+            }
+
+            let otlp_exporter = otlp_exporter_builder.build()?;
 
             let tracer_provider = opentelemetry_sdk::trace::TracerProvider::builder()
                 .with_resource(opentelemetry_sdk::Resource::new(vec![