kubernix 0.3.1

//! Configuration related structures
use crate::{podman::Podman, system::System};
use anyhow::{Context, Result};
use clap::{Parser, Subcommand as ClapSubcommand, ValueEnum, builder::styling};
use ipnetwork::Ipv4Network;
use log::LevelFilter;
use serde::{Deserialize, Serialize};
use std::{
    fmt,
    fs::{self, canonicalize, create_dir_all, read_to_string},
    path::{Path, PathBuf},
};

/// Output format for log messages
#[derive(Clone, Copy, Debug, Default, Deserialize, PartialEq, Eq, Serialize, ValueEnum)]
#[serde(rename_all = "lowercase")]
pub enum LogFormat {
    /// Human-readable colored text (default)
    #[default]
    Text,
    /// Machine-readable JSON, one object per line
    Json,
}

impl fmt::Display for LogFormat {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            LogFormat::Text => write!(f, "text"),
            LogFormat::Json => write!(f, "json"),
        }
    }
}

#[derive(Clone, Parser, Deserialize, Serialize)]
#[serde(rename_all = "kebab-case")]
#[command(
    after_help = "More info at: https://github.com/saschagrunert/kubernix",
    author = "Sascha Grunert <mail@saschagrunert.de>",
    version,
    styles = styling::Styles::styled()
        .header(styling::AnsiColor::Green.on_default().bold())
        .usage(styling::AnsiColor::Green.on_default().bold())
        .literal(styling::AnsiColor::Cyan.on_default().bold())
        .placeholder(styling::AnsiColor::Cyan.on_default())
)]
/// The global configuration
pub struct Config {
    #[command(subcommand)]
    /// All available subcommands
    subcommand: Option<SubCommand>,

    #[arg(
        default_value = "kubernix-run",
        env = "KUBERNIX_ROOT",
        global = true,
        long = "root",
        short = 'r',
        value_name = "PATH"
    )]
    /// Path where all the runtime data is stored
    root: PathBuf,

    #[arg(
        default_value = "info",
        env = "KUBERNIX_LOG_LEVEL",
        long = "log-level",
        short = 'l',
        value_name = "LEVEL"
    )]
    /// The logging level of the application
    log_level: LevelFilter,

    #[arg(
        default_value = "text",
        env = "KUBERNIX_LOG_FORMAT",
        long = "log-format",
        short = 'f',
        value_name = "FORMAT"
    )]
    /// The output format for log messages
    log_format: LogFormat,

    #[arg(
        default_value = "10.10.0.0/16",
        env = "KUBERNIX_CIDR",
        long = "cidr",
        short = 'c',
        value_name = "CIDR"
    )]
    /// The CIDR used for the cluster
    cidr: Ipv4Network,

    #[arg(
        env = "KUBERNIX_OVERLAY",
        long = "overlay",
        short = 'o',
        value_name = "PATH"
    )]
    /// The Nix package overlay to be used
    overlay: Option<PathBuf>,

    #[arg(
        env = "KUBERNIX_PACKAGES",
        long = "packages",
        num_args = 1..,
        short = 'p',
        value_name = "PACKAGE",
    )]
    /// Additional dependencies to be added to the environment
    packages: Vec<String>,

    #[arg(
        env = "KUBERNIX_SHELL",
        long = "shell",
        short = 's',
        value_name = "SHELL"
    )]
    /// The shell executable to be used, defaults to $SHELL, fallback is `sh`
    shell: Option<String>,

    #[arg(
        default_value = "1",
        env = "KUBERNIX_NODES",
        long = "nodes",
        short = 'n',
        value_name = "NODES"
    )]
    /// The number of nodes to be registered
    nodes: u8,

    #[arg(
        env = "KUBERNIX_CONTAINER_RUNTIME",
        long = "container-runtime",
        default_value = Podman::EXECUTABLE,
        requires = "nodes",
        short = 'u',
        value_name = "RUNTIME",
    )]
    /// The container runtime to be used for the nodes, irrelevant if `nodes` equals to `1`
    container_runtime: String,

    #[arg(
        conflicts_with = "shell",
        env = "KUBERNIX_NO_SHELL",
        long = "no-shell",
        short = 'e'
    )]
    /// Do not spawn an interactive shell after bootstrap
    no_shell: bool,

    #[arg(
        env = "KUBERNIX_DOCKERFILE",
        long = "dockerfile",
        short = 'd',
        value_name = "PATH"
    )]
    /// Custom Dockerfile path for multi-node container image builds
    dockerfile: Option<PathBuf>,

    #[arg(
        default_value = "coredns",
        env = "KUBERNIX_ADDONS",
        long = "addons",
        short = 'a',
        num_args = 0..,
        value_name = "ADDON",
    )]
    /// Cluster addons to deploy (available: coredns)
    addons: Vec<String>,
}

impl Config {
    /// The active subcommand, if any (e.g. `shell`).
    pub fn subcommand(&self) -> &Option<SubCommand> {
        &self.subcommand
    }

    /// Directory where all runtime data is stored.
    pub fn root(&self) -> &Path {
        &self.root
    }

    /// Configured log verbosity level.
    pub fn log_level(&self) -> LevelFilter {
        self.log_level
    }

    /// Output format for log messages (text or JSON).
    pub fn log_format(&self) -> LogFormat {
        self.log_format
    }

    /// Parent CIDR from which cluster, service, and pod subnets are carved.
    pub fn cidr(&self) -> Ipv4Network {
        self.cidr
    }

    /// Custom Nix package overlay path, if provided via `--overlay`.
    pub fn overlay(&self) -> Option<&Path> {
        self.overlay.as_deref()
    }

    /// Additional Nix packages to include in the runtime environment.
    pub fn packages(&self) -> &[String] {
        &self.packages
    }

    /// Interactive shell executable (defaults to `$SHELL`, fallback `sh`).
    pub fn shell(&self) -> Option<&str> {
        self.shell.as_deref()
    }

    /// Number of cluster nodes to register.
    pub fn nodes(&self) -> u8 {
        self.nodes
    }

    /// Container runtime executable used for multi-node setups.
    pub fn container_runtime(&self) -> &str {
        &self.container_runtime
    }

    /// Whether to skip spawning an interactive shell after bootstrap.
    pub fn no_shell(&self) -> bool {
        self.no_shell
    }

    /// Custom Dockerfile path for multi-node container image builds.
    pub fn dockerfile(&self) -> Option<&Path> {
        self.dockerfile.as_deref()
    }

    /// Cluster addons to deploy after bootstrap (e.g. `coredns`).
    pub fn addons(&self) -> &[String] {
        &self.addons
    }
}

/// Possible subcommands
#[derive(Clone, ClapSubcommand, Deserialize, Serialize)]
pub enum SubCommand {
    /// Spawn an additional shell session
    #[command(name = "shell")]
    Shell,
}

impl Default for Config {
    fn default() -> Self {
        let mut config = Self::parse();
        if config.shell.is_none() {
            config.shell = System::shell().ok();
        }
        config
    }
}

impl Config {
    const FILENAME: &'static str = "kubernix.toml";

    /// Make the configs root path absolute
    pub fn canonicalize_root(&mut self) -> Result<()> {
        self.create_root_dir()?;
        self.root = canonicalize(self.root()).with_context(|| {
            format!(
                "Unable to canonicalize config root directory '{}'",
                self.root().display()
            )
        })?;
        Ok(())
    }

    /// Write the current configuration to the internal set root path
    pub fn to_file(&self) -> Result<()> {
        self.create_root_dir()?;
        fs::write(self.root().join(Self::FILENAME), toml::to_string(&self)?)
            .context("Unable to write configuration to file")?;
        Ok(())
    }

    /// Read the configuration from the internal set root path
    /// If not existing, write the current configuration to the path.
    pub fn try_load_file(&mut self) -> Result<()> {
        let file = self.root().join(Self::FILENAME);
        if file.exists() {
            *self = toml::from_str(&read_to_string(&file).with_context(|| {
                format!(
                    "Unable to read expected configuration file '{}'",
                    file.display(),
                )
            })?)
            .with_context(|| format!("Unable to load config file '{}'", file.display()))?;
        } else {
            self.to_file()?;
        }
        Ok(())
    }

    /// Return the set shell as result type
    pub fn shell_ok(&self) -> Result<String> {
        let shell = self.shell.as_ref().context("No shell set")?;
        Ok(shell.into())
    }

    /// Returns true if multi node support is enabled
    pub fn multi_node(&self) -> bool {
        self.nodes() > 1
    }

    fn create_root_dir(&self) -> Result<()> {
        create_dir_all(self.root()).with_context(|| {
            format!(
                "Unable to create root directory '{}'",
                self.root().display()
            )
        })
    }
}

#[cfg(test)]
pub mod tests {
    use super::*;
    use std::path::Path;
    use tempfile::tempdir;

    pub fn test_config() -> Result<Config> {
        let mut c = Config::parse_from(&[] as &[&str]);
        if c.shell.is_none() {
            c.shell = System::shell().ok();
        }
        c.root = tempdir()?.keep();
        c.canonicalize_root()?;
        Ok(c)
    }

    pub fn test_config_wrong_root() -> Result<Config> {
        let mut c = test_config()?;
        c.root = Path::new("/").join("proc");
        Ok(c)
    }

    pub fn test_config_wrong_cidr() -> Result<Config> {
        let mut c = test_config()?;
        c.cidr = "10.0.0.1/31".parse()?;
        Ok(c)
    }

    #[test]
    fn canonicalize_root_success() -> Result<()> {
        let mut c = Config::default();
        c.root = tempdir()?.keep();
        c.canonicalize_root()
    }

    #[test]
    fn canonicalize_root_failure() {
        let mut c = Config::default();
        c.root = Path::new("/").join("proc").join("invalid");
        assert!(c.canonicalize_root().is_err())
    }

    #[test]
    fn to_file_success() -> Result<()> {
        let mut c = Config::default();
        c.root = tempdir()?.keep();
        c.to_file()
    }

    #[test]
    fn to_file_failure() {
        let mut c = Config::default();
        c.root = Path::new("/").join("proc").join("invalid");
        assert!(c.to_file().is_err())
    }

    #[test]
    fn try_load_file_success() -> Result<()> {
        let mut c = Config::default();
        c.root = tempdir()?.keep();
        fs::write(
            c.root.join(Config::FILENAME),
            r#"
addons = ["coredns"]
cidr = "1.1.1.1/16"
container-runtime = "podman"
log-format = "text"
log-level = "DEBUG"
no-shell = false
nodes = 1
packages = []
root = "root"
            "#,
        )?;
        c.try_load_file()?;
        assert_eq!(c.root(), Path::new("root"));
        assert_eq!(c.log_level(), LevelFilter::Debug);
        assert_eq!(c.log_format(), LogFormat::Text);
        assert_eq!(&c.cidr().to_string(), "1.1.1.1/16");
        assert!(c.dockerfile().is_none());
        Ok(())
    }

    #[test]
    fn try_load_file_with_dockerfile() -> Result<()> {
        let mut c = Config::default();
        c.root = tempdir()?.keep();
        fs::write(
            c.root.join(Config::FILENAME),
            r#"
addons = ["coredns"]
cidr = "1.1.1.1/16"
container-runtime = "podman"
dockerfile = "/tmp/MyDockerfile"
log-format = "json"
log-level = "DEBUG"
no-shell = false
nodes = 1
packages = []
root = "root"
            "#,
        )?;
        c.try_load_file()?;
        assert_eq!(c.log_format(), LogFormat::Json);
        assert_eq!(c.dockerfile(), Some(Path::new("/tmp/MyDockerfile")));
        Ok(())
    }

    #[test]
    fn try_load_file_failure() -> Result<()> {
        let mut c = Config::default();
        c.root = tempdir()?.keep();
        fs::write(c.root.join(Config::FILENAME), "invalid")?;
        assert!(c.try_load_file().is_err());
        Ok(())
    }
}