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

dre_protocol/
lib.rs
