metrics-cache: make push interval configurable

CMK-36784

Author: DavidGerva

charts/cmk-rustik/templates/metrics-cache/deployment.yaml

@@ -63,6 +63,7 @@ spec:
             {{- end }}
             {{- if .Values.push.enabled }}
             - --push-receiver={{ required "push.url is required when push mode is enabled" .Values.push.url }}
+            - --push-interval={{ .Values.push.interval }}
             {{- if .Values.push.insecureSkipSiteCaVerification }}
             - --push-registration-insecure-skip-site-ca-verification
             {{- end }}

charts/cmk-rustik/values.yaml

@@ -130,6 +130,9 @@ push:
   # been warned. When set to true, will trust whatever push-agent receiver
   # answers at the configured URL, without verifying its identity.
   insecureSkipSiteCaVerification: false
+  # interval is how often, in seconds, sections are generated and pushed to
+  # the Checkmk site. Must be greater than zero.
+  interval: 60
 
 # pull allows you to configure pull mode, so that Checkmk's special agent can
 # query the agent directly.

metrics-cache/src/cli_args.rs

@@ -1,6 +1,7 @@
 use clap::Parser;
 use regex::Regex;
 use std::time::Duration;
+use thiserror::Error;
 
 pub struct TlsConfig {
     pub secret_name: Option<String>,
@@ -183,6 +184,14 @@ pub struct CliArgs {
     #[arg(long, env = "CMK_PULL_SHARED_SECRET", hide_env_values = true)]
     pub pull_shared_secret: Option<String>,
 
+    /// Push interval in seconds for push mode. Ignored if push mode is not enabled.
+    #[arg(
+        long = "push-interval",
+        value_parser = parse_push_interval,
+        default_value = "60"
+    )]
+    pub push_interval: Duration,
+
     /// Enable push mode and send sections to the specified server (including
     /// port)
     #[arg(long = "push-receiver")]
@@ -278,6 +287,23 @@ fn parse_duration_days(arg: &str) -> Result<Duration, std::num::ParseIntError> {
     Ok(Duration::from_secs(60 * 60 * 24 * days))
 }
 
+#[derive(Error, Debug)]
+enum PushIntervalError {
+    #[error("must be a whole number of seconds")]
+    NotANumber(#[from] std::num::ParseIntError),
+    #[error("must be greater than zero")]
+    Zero,
+}
+
+fn parse_push_interval(arg: &str) -> Result<Duration, PushIntervalError> {
+    let interval = parse_duration_secs(arg)?;
+    // if 0, tokio panics
+    match interval.is_zero() {
+        true => Err(PushIntervalError::Zero),
+        false => Ok(interval),
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -371,4 +397,21 @@ mod tests {
             );
         }
     }
+
+    #[test]
+    fn push_interval_parse_correctly() {
+        for interval in ["1", "80"] {
+            assert!(parse(&["--push-interval", interval]).is_ok());
+        }
+    }
+
+    #[test]
+    fn push_interval_cannot_be_zero() {
+        assert_eq!(
+            parse(&["--push-interval", "0"])
+                .expect_err("push interval of zero should fail")
+                .kind(),
+            ErrorKind::ValueValidation
+        );
+    }
 }

metrics-cache/src/main.rs

@@ -152,7 +152,7 @@ async fn main() -> anyhow::Result<()> {
         // Push to Checkmk server
         res = async {
             match push_client {
-                Some(client) => push_loop(client, state.clone()).await,
+                Some(client) => push_loop(client, state.clone(), args.push_interval).await,
                 None => std::future::pending().await,
             }
         } => {

metrics-cache/src/push/mod.rs

@@ -68,9 +68,10 @@ async fn push_cycle(
 pub async fn push_loop(
     client: CheckmkPushClient,
     state: AppState<impl TokenValidator>,
+    push_interval: Duration,
 ) -> Result<(), WriterDropped> {
     state.stores.wait_until_all_ready().await?;
-    let mut interval = time::interval(Duration::from_secs(60)); // TODO: Unhardcode
+    let mut interval = time::interval(push_interval);
     loop {
         interval.tick().await; // note: The very first tick() is no-op
         match push_cycle(&client, &state).await {