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//! The `kubectl` calls the proof of concept makes.
//!
//! The real executor would use a Kubernetes client crate. The proof of
//! concept shells out to `kubectl` for the same reason knotless's docker
//! executor shells out to `docker`: the transport is visible, and a fake
//! client in the tests can show every call.
use std::io::Write;
use std::path::{Path, PathBuf};
use std::process::{Child, Command, Stdio};
use std::time::Duration;
use crate::cli::Options;
/// A configured `kubectl` client.
#[derive(Clone, Debug)]
pub struct Kubectl {
program: PathBuf,
kubeconfig: Option<PathBuf>,
context: Option<String>,
namespace: String,
}
impl Kubectl {
pub fn new(options: &Options) -> Self {
Self {
program: options.kubectl.clone(),
kubeconfig: options.kubeconfig.clone(),
context: options.context.clone(),
namespace: options.namespace.clone(),
}
}
/// The client with its kubeconfig, context and namespace.
fn base(&self) -> Command {
let mut command = Command::new(&self.program);
if let Some(kubeconfig) = &self.kubeconfig {
command.arg("--kubeconfig").arg(kubeconfig);
}
if let Some(context) = &self.context {
command.arg("--context").arg(context);
}
command.args(["-n", &self.namespace]);
command
}
/// A readable line for `--dry-run`, as a shell would take it.
pub fn planned(&self, args: &[&str]) -> String {
let mut parts = vec![self.program.display().to_string()];
if let Some(kubeconfig) = &self.kubeconfig {
parts.push("--kubeconfig".into());
parts.push(kubeconfig.display().to_string());
}
if let Some(context) = &self.context {
parts.push("--context".into());
parts.push(context.clone());
}
parts.push("-n".into());
parts.push(self.namespace.clone());
parts.extend(args.iter().map(|a| shell_word(a)));
parts.join(" ")
}
/// Applies the Job manifest from stdin.
pub fn apply(&self, manifest: &str) -> Result<(), String> {
let mut child = self
.base()
.args(["apply", "-f", "-"])
.stdin(Stdio::piped())
.spawn()
.map_err(|err| format!("running {}: {err}", self.program.display()))?;
{
let mut stdin = child
.stdin
.take()
.ok_or_else(|| "kubectl apply: no stdin".to_string())?;
stdin
.write_all(manifest.as_bytes())
.map_err(|err| format!("writing the Job manifest: {err}"))?;
}
let status = child
.wait()
.map_err(|err| format!("waiting for kubectl apply: {err}"))?;
if !status.success() {
return Err("kubectl apply failed".to_string());
}
Ok(())
}
/// Waits for the Job's pod to be Ready.
pub fn wait_pod(&self, job: &str, timeout: Duration) -> Result<(), String> {
let selector = format!("job-name={job}");
let timeout = format!("{}s", timeout.as_secs().max(1));
let status = self
.base()
.args([
"wait",
"--for=condition=Ready",
"pod",
"-l",
&selector,
"--timeout",
&timeout,
])
.status()
.map_err(|err| format!("running kubectl wait: {err}"))?;
if !status.success() {
return Err(format!("pod for Job {job} did not become Ready"));
}
Ok(())
}
/// The first pod of the Job.
pub fn pod(&self, job: &str) -> Result<String, String> {
let selector = format!("job-name={job}");
let output = self
.base()
.args([
"get",
"pods",
"-l",
&selector,
"-o",
"jsonpath={.items[0].metadata.name}",
])
.output()
.map_err(|err| format!("running kubectl get pods: {err}"))?;
if !output.status.success() {
let stderr = String::from_utf8_lossy(&output.stderr);
return Err(format!("kubectl get pods failed: {}", stderr.trim()));
}
let pod = String::from_utf8_lossy(&output.stdout).trim().to_string();
if pod.is_empty() {
return Err(format!("Job {job} has no pod"));
}
Ok(pod)
}
/// The command that runs `script` in `pod` as a step.
pub fn exec(&self, pod: &str, script: &str) -> Command {
let mut command = self.base();
command.args(["exec", pod, "--", "sh", "-ec", script]);
command
}
/// Makes the directories the run streams into.
pub fn mkdirs(&self, pod: &str) -> Result<(), String> {
let status = self
.base()
.args(["exec", pod, "--", "mkdir", "-p", "/work", "/outputs", "/steps"])
.status()
.map_err(|err| format!("running kubectl exec mkdir: {err}"))?;
if !status.success() {
return Err("creating /work, /outputs and /steps in the pod failed".to_string());
}
Ok(())
}
/// Streams the contents of `source` on this host into `dest` in `pod`,
/// over `kubectl exec -i` and tar, which Kubernetes has in place of a
/// file copy API.
pub fn tar_in(&self, pod: &str, dest: &str, source: &Path) -> Result<(), String> {
let mut tar = Command::new("tar")
.args(["-cf", "-", "-C"])
.arg(source)
.arg(".")
.stdout(Stdio::piped())
.spawn()
.map_err(|err| format!("running tar for {}: {err}", source.display()))?;
let stdout = tar
.stdout
.take()
.ok_or_else(|| "tar: no stdout".to_string())?;
let mut kubectl = self.base();
kubectl
.args(["exec", "-i", pod, "--", "tar", "-xf", "-", "-C", dest])
.stdin(Stdio::from(stdout))
.stdout(Stdio::null());
let status = wait(
kubectl
.spawn()
.map_err(|err| format!("running kubectl exec tar: {err}"))?,
"kubectl exec tar",
)?;
let tar_status = wait(tar, "tar")?;
if !status.success() {
return Err(format!(
"streaming {} into {dest} failed",
source.display()
));
}
if !tar_status.success() {
return Err(format!("tar reading {} failed", source.display()));
}
Ok(())
}
/// Streams the contents of `source` in `pod` into `dest` on this host.
pub fn tar_out(&self, pod: &str, source: &str, dest: &Path) -> Result<(), String> {
let mut kubectl = self.base();
kubectl
.args(["exec", pod, "--", "tar", "-cf", "-", "-C", source, "."])
.stdout(Stdio::piped());
let mut kubectl = kubectl
.spawn()
.map_err(|err| format!("running kubectl exec tar: {err}"))?;
let stdout = kubectl
.stdout
.take()
.ok_or_else(|| "kubectl exec tar: no stdout".to_string())?;
let tar = Command::new("tar")
.args(["-xf", "-", "-C"])
.arg(dest)
.stdin(Stdio::from(stdout))
.spawn()
.map_err(|err| format!("running tar for {}: {err}", dest.display()))?;
let status = wait(kubectl, "kubectl exec tar")?;
let tar_status = wait(tar, "tar")?;
if !status.success() {
return Err(format!("streaming {source} out of the pod failed"));
}
if !tar_status.success() {
return Err(format!("tar writing {} failed", dest.display()));
}
Ok(())
}
/// Deletes the Job and its pod. Missing is fine.
pub fn delete(&self, job: &str) -> Result<(), String> {
let status = self
.base()
.args(["delete", "job", job, "--ignore-not-found", "--wait=false"])
.status()
.map_err(|err| format!("running kubectl delete: {err}"))?;
if !status.success() {
return Err(format!("kubectl delete job {job} failed"));
}
Ok(())
}
}
fn wait(mut child: Child, what: &str) -> Result<std::process::ExitStatus, String> {
child
.wait()
.map_err(|err| format!("waiting for {what}: {err}"))
}
/// A shell-ish word for a dry-run line, quoted only when it has spaces.
fn shell_word(word: &str) -> String {
if word.is_empty()
|| word
.chars()
.any(|c| c.is_whitespace() || matches!(c, '\'' | '"' | '$' | '`' | '\\'))
{
format!("'{}'", word.replace('\'', "'\\''"))
} else {
word.to_string()
}
}
#[cfg(test)]
mod tests {
use super::*;
fn client() -> Kubectl {
Kubectl {
program: PathBuf::from("kubectl"),
kubeconfig: Some(PathBuf::from("/k")),
context: Some("ctx".into()),
namespace: "ci".into(),
}
}
#[test]
fn plans() {
assert_eq!(
client().planned(&["exec", "pod", "--", "sh", "-ec", "echo hi"]),
"kubectl --kubeconfig /k --context ctx -n ci exec pod -- sh -ec 'echo hi'"
);
}
#[test]
fn exec_args() {
let command = client().exec("pod-1", "make test");
let args: Vec<_> = command.get_args().map(|a| a.to_string_lossy()).collect();
assert_eq!(
args,
vec![
"--kubeconfig",
"/k",
"--context",
"ctx",
"-n",
"ci",
"exec",
"pod-1",
"--",
"sh",
"-ec",
"make test"
]
);
}
}
