cufflink-cli 0.20.0

//! What a platform says it is and supports (`GET /api/version`), and what
//! a deploy and `cufflink --version` print of it.

use crate::config::CliConfig;
use serde::{Deserialize, Deserializer};
use serde_json::Value;
use std::collections::BTreeSet;
use std::process::Command;

const CLI_VERSION: &str = env!("CARGO_PKG_VERSION");
const SDK: &str = "cufflink-fn";

/// What `GET /api/version` answers, read as the CLI read it before it had
/// a type for it: a field of another type is as if it were absent, and an
/// entry of `supports` that is not a name is passed over.
#[derive(Debug, Default, PartialEq, Eq, Deserialize)]
pub struct PlatformVersion {
    #[serde(default, deserialize_with = "number")]
    pub api_version: u32,
    #[serde(default, deserialize_with = "text")]
    pub platform_version: Option<String>,
    #[serde(default, deserialize_with = "names")]
    pub supports: Vec<String>,
}

fn number<'de, D: Deserializer<'de>>(field: D) -> Result<u32, D::Error> {
    Ok(Value::deserialize(field)?
        .as_u64()
        .and_then(|n| u32::try_from(n).ok())
        .unwrap_or(0))
}

fn text<'de, D: Deserializer<'de>>(field: D) -> Result<Option<String>, D::Error> {
    Ok(Value::deserialize(field)?.as_str().map(str::to_string))
}

fn names<'de, D: Deserializer<'de>>(field: D) -> Result<Vec<String>, D::Error> {
    Ok(Value::deserialize(field)?
        .as_array()
        .into_iter()
        .flatten()
        .filter_map(|entry| entry.as_str().map(str::to_string))
        .collect())
}

/// `0.27.0` as `v0.27.0`; a build stamp (`sha-…`) as it is.
fn labelled(version: &str) -> String {
    if version.starts_with(|c: char| c.is_ascii_digit()) {
        format!("v{version}")
    } else {
        version.to_string()
    }
}

fn listed(names: &[String]) -> String {
    if names.is_empty() {
        "none".to_string()
    } else {
        names.join(", ")
    }
}

impl PlatformVersion {
    fn label(&self) -> String {
        self.platform_version
            .as_deref()
            .map_or_else(|| "of an unknown version".to_string(), labelled)
    }
}

/// The versions of the SDK a `cargo metadata` resolved.
fn sdk_versions(metadata: &Value) -> BTreeSet<String> {
    metadata["packages"]
        .as_array()
        .into_iter()
        .flatten()
        .filter(|package| package["name"] == SDK)
        .filter_map(|package| package["version"].as_str())
        .map(labelled)
        .collect()
}

/// The SDK the project in the working directory builds with, when Cargo
/// can say.
pub fn sdk_version() -> Option<String> {
    Command::new("cargo")
        .args(["metadata", "--format-version", "1"])
        .output()
        .ok()
        .filter(|output| output.status.success())
        .and_then(|output| serde_json::from_slice::<Value>(&output.stdout).ok())
        .map(|metadata| sdk_versions(&metadata))
        .filter(|versions| !versions.is_empty())
        .map(|versions| versions.into_iter().collect::<Vec<_>>().join(", "))
}

/// `platform vX (features …) ← sdk vY (needs …)`: what a deploy is
/// offered and what it asks for.
pub fn negotiated(platform: &PlatformVersion, sdk: Option<&str>, manifest: &Value) -> String {
    let needs: Vec<String> = manifest["required_platform_features"]
        .as_array()
        .into_iter()
        .flatten()
        .filter_map(Value::as_str)
        .map(str::to_string)
        .collect();
    format!(
        "platform {} (features {}) ← sdk {} (needs {})",
        platform.label(),
        listed(&platform.supports),
        sdk.unwrap_or("of an unknown version"),
        listed(&needs)
    )
}

fn described(api_url: &str, platform: &PlatformVersion) -> String {
    format!(
        "platform {} at {api_url} (deploy API {})\nfeatures {}",
        platform.label(),
        platform.api_version,
        listed(&platform.supports)
    )
}

/// `cufflink --version`: the CLI's, and with `--env` the platform's.
pub async fn print(env: Option<&str>) -> eyre::Result<()> {
    println!("cufflink {CLI_VERSION}");
    if env.is_some() {
        let config = CliConfig::load_with_env(env)?;
        let url = format!("{}/api/version", config.api_url);
        let asked = config
            .http_client()
            .get(&url)
            .send()
            .await
            .map_err(|e| eyre::eyre!("Could not reach the platform at {url}: {e}"))?;
        let status = asked.status();
        if !status.is_success() {
            eyre::bail!("{url} answered {status}");
        }
        println!("{}", described(&config.api_url, &asked.json().await?));
    }
    Ok(())
}

#[cfg(test)]
mod tests {
    use super::*;
    use serde_json::json;

    fn platform(version: Option<&str>, supports: &[&str]) -> PlatformVersion {
        PlatformVersion {
            api_version: 1,
            platform_version: version.map(str::to_string),
            supports: supports.iter().map(|s| s.to_string()).collect(),
        }
    }

    #[test]
    fn a_deploy_says_what_the_platform_offers_and_the_service_needs() {
        let offered = platform(
            Some("sha-4f2a"),
            &["bundled_wasm", "db_v2", "route_posture"],
        );
        assert_eq!(
            negotiated(
                &offered,
                Some("v0.27.0"),
                &json!({"required_platform_features": ["db_v2", "route_posture"]})
            ),
            "platform sha-4f2a (features bundled_wasm, db_v2, route_posture) ← sdk v0.27.0 \
             (needs db_v2, route_posture)"
        );
        assert_eq!(
            negotiated(
                &platform(Some("0.27.0"), &[]),
                None,
                &json!({"name": "notes"})
            ),
            "platform v0.27.0 (features none) ← sdk of an unknown version (needs none)"
        );
        assert_eq!(
            negotiated(&platform(None, &["streams"]), Some("v0.26.1"), &json!({})),
            "platform of an unknown version (features streams) ← sdk v0.26.1 (needs none)"
        );
    }

    #[test]
    fn the_sdk_is_every_version_of_it_cargo_resolved() {
        let metadata = json!({"packages": [
            {"name": "cufflink-fn", "version": "0.27.0"},
            {"name": "cufflink", "version": "0.11.0"},
            {"name": "cufflink-fn", "version": "0.26.1"},
            {"name": "cufflink-fn", "version": "0.27.0"},
        ]});
        assert_eq!(
            sdk_versions(&metadata).into_iter().collect::<Vec<_>>(),
            ["v0.26.1", "v0.27.0"]
        );
        assert!(sdk_versions(&json!({})).is_empty());
    }

    #[test]
    fn a_platform_is_read_from_what_it_answers() {
        let answered: PlatformVersion = serde_json::from_value(json!({
            "api_version": 1,
            "platform_version": "sha-4f2a",
            "supports": ["bundled_wasm", "streams"],
        }))
        .expect("a platform");
        assert_eq!(
            answered,
            platform(Some("sha-4f2a"), &["bundled_wasm", "streams"])
        );
        assert_eq!(
            described("http://localhost:8080", &answered),
            "platform sha-4f2a at http://localhost:8080 (deploy API 1)\n\
             features bundled_wasm, streams"
        );
        let silent: PlatformVersion = serde_json::from_value(json!({})).expect("a platform");
        assert_eq!(silent, PlatformVersion::default());
        let odd: PlatformVersion = serde_json::from_value(json!({
            "api_version": "1",
            "platform_version": 7,
            "supports": ["bundled_wasm", 7, {"streams": true}, "streams"],
        }))
        .expect("a platform that answers what is not of its type");
        assert_eq!(
            odd,
            PlatformVersion {
                api_version: 0,
                ..platform(None, &["bundled_wasm", "streams"])
            }
        );
        let unlisted: PlatformVersion =
            serde_json::from_value(json!({"supports": "all"})).expect("a platform");
        assert!(unlisted.supports.is_empty());
    }
}