dre_protocol/
lib.rs

1//! The DRE plugin protocol, version 1.
2//!
3//! Plugins ship in packages: one executable, `dre-plugin-<package>`, serving every plugin the
4//! package provides (a single plugin may also be named `dre-<kind>-<name>`). It talks to DRE core
5//! over stdin/stdout in length-prefixed frames. Each frame is a JSON control message or an Arrow IPC stream; plugins
6//! log through `log` messages, and stderr carries what can't (panics, native drivers). See `docs/protocol.md` in the repository for the public contract.
7//!
8//! - [`frame`]: the wire format.
9//! - [`msg`]: every control message.
10//! - [`host`]: the core side: spawning a plugin, the handshake, requests.
11//! - [`plugin`]: the SDK plugin authors use to serve requests.
12//! - [`options`]: the options a plugin declares, and how they're checked.
13//! - [`conformance`]: checks any plugin binary against the protocol.
14//! - [`sessions`]: OAuth sessions plugins keep in `~/.dre/oauth_sessions.json`.
15//! - [`markdown`]: the portable Markdown subset of messages, and its translations.
16//! - [`delivery`]: the delivery and network rules every file destination shares.
17
18// A public function that can panic says when in a `# Panics` section (CI denies warnings).
19#![warn(clippy::missing_panics_doc)]
20
21/// The `log` crate, re-exported: plugins log with `dre_protocol::log::info!` and friends, which
22/// the SDK sends to core as `log` messages.
23pub use log;
24
25pub mod conformance;
26pub mod connection;
27pub mod delivery;
28pub mod frame;
29#[cfg(target_os = "linux")]
30mod fuse_fds;
31pub mod host;
32pub mod markdown;
33pub mod msg;
34pub mod options;
35pub mod plugin;
36pub mod sessions;
37pub mod style;
38pub mod util;
39
40/// This crate's version (its own, not DRE's); the fixture plugins report it.
41pub const CRATE_VERSION: &str = env!("CARGO_PKG_VERSION");
42
43/// Protocol versions the plugin SDK speaks: a plugin built on it also works with an older core.
44pub const MIN_VERSION: u32 = 0;
45pub const MAX_VERSION: u32 = 1;
46/// The oldest protocol version core accepts from a plugin.
47pub const CORE_MIN_VERSION: u32 = 1;
48
49/// Capability: can hold one session (and its temp objects) across requests.
50pub const CAP_SESSIONS: &str = "sessions";
51/// Capability: can open a connection read-only.
52pub const CAP_READ_ONLY: &str = "read_only";
53/// Capability: can verify a statement without executing it.
54pub const CAP_CHECK: &str = "check";
55/// Capability (destinations): takes every file of one output in a single `deliver`.
56pub const CAP_MULTI_FILE: &str = "multi_file";
57/// Capability (destinations): takes a message (`deliver` with `message`), not only files.
58pub const CAP_MESSAGE: &str = "message";
59/// Capability (destinations): takes only messages; core never sends it a file output.
60pub const CAP_MESSAGE_ONLY: &str = "message_only";
61/// Source: loads rows into a temporary table on the session (`load`), for large lookups.
62pub const CAP_LOAD: &str = "load";
63/// Answers `validate` (checks a config block of options). The Rust SDK always advertises it.
64pub const CAP_VALIDATE: &str = "validate";
65
66#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, serde::Serialize, serde::Deserialize)]
67#[serde(rename_all = "lowercase")]
68pub enum Kind {
69    Source,
70    Format,
71    Destination,
72}
73
74impl Kind {
75    pub fn as_str(self) -> &'static str {
76        match self {
77            Kind::Source => "source",
78            Kind::Format => "format",
79            Kind::Destination => "destination",
80        }
81    }
82
83    /// Parse a kind, singular or plural (`source`, `sources`).
84    pub fn parse(s: &str) -> Option<Kind> {
85        match s {
86            "source" | "sources" => Some(Kind::Source),
87            "format" | "formats" => Some(Kind::Format),
88            "destination" | "destinations" => Some(Kind::Destination),
89            _ => None,
90        }
91    }
92}
93
94impl std::fmt::Display for Kind {
95    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
96        f.write_str(self.as_str())
97    }
98}
99
100/// One plugin: its kind and name. Written `<kind>/<name>` (`destination/s3`), in messages as
101/// well as in `dre.lock`.
102#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
103pub struct PluginId {
104    pub kind: Kind,
105    pub name: String,
106}
107
108impl PluginId {
109    pub fn new(kind: Kind, name: impl Into<String>) -> PluginId {
110        PluginId {
111            kind,
112            name: name.into(),
113        }
114    }
115}
116
117impl std::fmt::Display for PluginId {
118    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
119        write!(f, "{}/{}", self.kind, self.name)
120    }
121}
122
123impl std::str::FromStr for PluginId {
124    type Err = String;
125
126    fn from_str(s: &str) -> Result<PluginId, String> {
127        let bad = || format!("`{s}` isn't `<kind>/<name>` (e.g. `destination/s3`)");
128        let (k, n) = s.split_once('/').ok_or_else(bad)?;
129        let kind = Kind::parse(k).ok_or_else(bad)?;
130        valid_name(n).then(|| PluginId::new(kind, n)).ok_or_else(bad)
131    }
132}
133
134impl serde::Serialize for PluginId {
135    fn serialize<S: serde::Serializer>(&self, s: S) -> Result<S::Ok, S::Error> {
136        s.collect_str(self)
137    }
138}
139
140impl<'de> serde::Deserialize<'de> for PluginId {
141    fn deserialize<D: serde::Deserializer<'de>>(d: D) -> Result<Self, D::Error> {
142        String::deserialize(d)?.parse().map_err(serde::de::Error::custom)
143    }
144}
145
146/// Whether `name` is a valid plugin or package name: `[a-z0-9_]+`.
147pub fn valid_name(name: &str) -> bool {
148    !name.is_empty()
149        && name
150            .bytes()
151            .all(|b| b.is_ascii_lowercase() || b.is_ascii_digit() || b == b'_')
152}
153
154/// The executable file name for a package on this platform: `dre-plugin-<package>`.
155pub fn package_executable_name(package: &str) -> String {
156    format!("dre-plugin-{package}{}", std::env::consts::EXE_SUFFIX)
157}
158
159/// Parse `dre-plugin-<package>[.exe]` into the package name.
160pub fn parse_package_executable_name(file: &str) -> Option<String> {
161    let stem = file.strip_suffix(std::env::consts::EXE_SUFFIX).unwrap_or(file);
162    if !std::env::consts::EXE_SUFFIX.is_empty() && stem == file {
163        return None;
164    }
165    let name = stem.strip_prefix("dre-plugin-")?;
166    valid_name(name).then(|| name.to_string())
167}
168
169/// The executable file name for a single plugin on this platform.
170pub fn executable_name(kind: Kind, name: &str) -> String {
171    format!("dre-{}-{name}{}", kind.as_str(), std::env::consts::EXE_SUFFIX)
172}
173
174/// Parse `dre-<kind>-<name>[.exe]` into its kind and name. Names are `[a-z0-9_]+`.
175pub fn parse_executable_name(file: &str) -> Option<(Kind, String)> {
176    let stem = file.strip_suffix(std::env::consts::EXE_SUFFIX).unwrap_or(file);
177    if !std::env::consts::EXE_SUFFIX.is_empty() && stem == file {
178        return None;
179    }
180    let rest = stem.strip_prefix("dre-")?;
181    let (kind, name) = rest.split_once('-')?;
182    let kind = Kind::parse(kind)?;
183    valid_name(name).then(|| (kind, name.to_string()))
184}
185
186#[cfg(test)]
187mod tests {
188    use super::*;
189
190    #[test]
191    fn parses_plugin_executable_names() {
192        let exe = |s: &str| format!("{s}{}", std::env::consts::EXE_SUFFIX);
193        assert_eq!(
194            parse_executable_name(&exe("dre-source-duckdb")),
195            Some((Kind::Source, "duckdb".into()))
196        );
197        assert_eq!(
198            parse_executable_name(&exe("dre-destination-azure_blob")),
199            Some((Kind::Destination, "azure_blob".into()))
200        );
201        assert_eq!(parse_executable_name(&exe("dre-format-csv.d")), None);
202        assert_eq!(parse_executable_name(&exe("dre-widget-x")), None);
203        assert_eq!(parse_executable_name(&exe("dre")), None);
204        assert_eq!(parse_executable_name(&exe("dre-plugin-csv")), None);
205    }
206
207    #[test]
208    fn parses_package_executable_names() {
209        let exe = |s: &str| format!("{s}{}", std::env::consts::EXE_SUFFIX);
210        assert_eq!(
211            parse_package_executable_name(&exe("dre-plugin-object_store")).as_deref(),
212            Some("object_store")
213        );
214        assert_eq!(parse_package_executable_name(&exe("dre-source-duckdb")), None);
215        assert_eq!(parse_package_executable_name(&exe("dre-plugin-")), None);
216    }
217
218    #[test]
219    fn plugin_ids_read_and_write_as_kind_slash_name() {
220        let id: PluginId = "destination/s3".parse().unwrap();
221        assert_eq!(id, PluginId::new(Kind::Destination, "s3"));
222        assert_eq!(id.to_string(), "destination/s3");
223        assert_eq!(serde_json::to_string(&id).unwrap(), "\"destination/s3\"");
224        assert!("s3".parse::<PluginId>().is_err());
225        assert!("widget/s3".parse::<PluginId>().is_err());
226    }
227}
dre_protocol/lib.rs

dre_protocol/
lib.rs
