kopium

Kubernetes openapi unmangler.

Generates rust structs from customresourcedefinitions in your kubernetes cluster follwing the spec/status model, by using their embedded openapi schema.

⚠️ WARNING: not feature complete ⚠️

Requirements:

• stable customresourcedefinition with schema
• crd following standard spec/status model

Features

• Instantly queryable: generated type uses kube-derive to provide api integration with kube
• Ergonomic Rust types: #[serde(default)] on Vec/BTreeMap over Option wrapping
• Rust doc comments: optionally extracted from description values in schema (--docs)

Installation

Grab a prebuilt musl/darwin binary from the latest release, or install from crates.io:

cargo install kopium

Usage

kopium prometheusrules.monitoring.coreos.com --docs > prometheusrule.rs

Output

use kube::CustomResource;
use serde::{Serialize, Deserialize};
use std::collections::BTreeMap;

/// Specification of desired alerting rule definitions for Prometheus.
#[derive(CustomResource, Serialize, Deserialize, Clone, Debug)]
#[kube(group = "monitoring.coreos.com", version = "v1", kind = "PrometheusRule", plural = "prometheusrules")]
#[kube(namespaced)]
#[kube(schema = "disabled")]
pub struct PrometheusRuleSpec {
    /// Content of Prometheus rule file
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub groups: Vec<PrometheusRuleGroups>,
}

/// RuleGroup is a list of sequentially evaluated recording and alerting rules. Note: PartialResponseStrategy is only used by ThanosRuler and will be ignored by Prometheus instances.  Valid values for this field are 'warn' or 'abort'.  More info: https://github.com/thanos-io/thanos/blob/master/docs/components/rule.md#partial-response
#[derive(Serialize, Deserialize, Clone, Debug)]
pub struct PrometheusRuleGroups {
    pub interval: Option<String>,
    pub name: String,
    pub partial_response_strategy: Option<String>,
    pub rules: Vec<PrometheusRuleGroupsRules>,
}

/// Rule describes an alerting or recording rule See Prometheus documentation: [alerting](https://www.prometheus.io/docs/prometheus/latest/configuration/alerting_rules/) or [recording](https://www.prometheus.io/docs/prometheus/latest/configuration/recording_rules/#recording-rules) rule
#[derive(Serialize, Deserialize, Clone, Debug)]
pub struct PrometheusRuleGroupsRules {
    pub alert: Option<String>,
    #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
    pub annotations: BTreeMap<String, String>,
    pub expr: String,
    pub r#for: Option<String>,
    #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
    pub labels: BTreeMap<String, String>,
    pub record: Option<String>,
}

Usage with kube

Simply add the generated file (e.g. output from above in prometheusrule.rs) to your library, and import (at least) the special root type:

use prometheusrule::PrometheusRule;
use kube::{Api, Client, ResourceExt};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let client = Client::try_default().await?;
    let pr: Api<PrometheusRule> = Api::default_namespaced(client);
    for p in pr.list(&Default::default()).await? {
        println!("Found PrometheusRule {} in current namespace", p.name());
    }
    Ok(())
}

Autocomplete

Autocompletion for most shells available via kopium completions:

source <(kopium completions bash)

Testing

Generate a CRD, tell the test runner to try to use it.

cargo run --bin kopium -- prometheusrules.monitoring.coreos.com > tests/gen.rs
echo "pub type CR = PrometheusRule;" >> tests/gen.rs
kubectl apply -f tests/pr.yaml # needs to contain a CR with name "gen"
cargo test --test runner -- --nocapture

test shortcuts available via just in the justfile.

License

Apache 2.0 licensed. See LICENSE for details.