faucet_source_redshift/
config.rs

1//! Amazon Redshift source configuration.
2
3use faucet_common_redshift::RedshiftConnection;
4use faucet_core::{DEFAULT_BATCH_SIZE, FaucetError};
5use schemars::JsonSchema;
6use serde::{Deserialize, Serialize};
7use serde_json::Value;
8
9/// How the Redshift source replicates rows across runs.
10///
11/// Serializes as `{ type: full }` or
12/// `{ type: incremental, column: "...", initial_value: ... }`.
13#[derive(Clone, Debug, Serialize, Deserialize, JsonSchema, Default, PartialEq)]
14#[serde(tag = "type", rename_all = "snake_case")]
15pub enum RedshiftReplication {
16    /// Every run re-fetches the full result set (default).
17    #[default]
18    Full,
19    /// Only rows not yet read, in `column` order, resuming from the stored
20    /// bookmark (or `initial_value` on the first run).
21    ///
22    /// The source wraps the query as
23    /// `SELECT * FROM (<query>) AS q WHERE q."column" >= CAST($n AS <type>) ORDER BY q."column"`
24    /// (the column's type as the server describes it) and drops the rows it
25    /// already emitted at the bookmark value, so rows that share a cursor
26    /// value (batch loads stamped with one `updated_at`, COPY jobs landing in
27    /// several commits) are never skipped. Every page carries a bookmark, so
28    /// a crash replays at most one page. Write `${bookmark}` in the query
29    /// (with `>=`) to apply the cursor further inside it; a strict `>` is
30    /// refused. Rows whose `column` is NULL are never read.
31    Incremental {
32        /// Column whose value is the replication cursor (e.g. `updated_at`).
33        column: String,
34        /// Lower bound (inclusive) used on the first run, before any bookmark
35        /// is stored.
36        initial_value: Value,
37    },
38}
39
40fn default_max_connections() -> u32 {
41    10
42}
43
44fn default_batch_size() -> usize {
45    DEFAULT_BATCH_SIZE
46}
47
48/// Configuration for the Amazon Redshift query source.
49#[derive(Clone, Debug, Serialize, Deserialize, JsonSchema)]
50pub struct RedshiftSourceConfig {
51    /// Connection block (host / port / database / user / credentials / tls),
52    /// flattened to the config top level.
53    #[serde(flatten)]
54    pub connection: RedshiftConnection,
55    /// SQL query to execute. May contain `${field.path}` parent-context tokens
56    /// (resolved to positional binds at runtime) and, for incremental
57    /// replication, a `${bookmark}` token.
58    #[schemars(extend("x-faucet-sql" = true))]
59    pub query: String,
60    /// Positional bind parameters for the query, applied in `$1, $2, …` order
61    /// before any context- or bookmark-derived values. Defaults to empty.
62    #[serde(default)]
63    pub params: Vec<Value>,
64    /// Maximum number of connections in the pool. Defaults to 10.
65    #[serde(default = "default_max_connections")]
66    pub max_connections: u32,
67    /// Records per emitted [`StreamPage`](faucet_core::StreamPage). Rows are
68    /// drained from the `sqlx` cursor and yielded whenever the buffer reaches
69    /// this size. Defaults to [`DEFAULT_BATCH_SIZE`].
70    ///
71    /// `batch_size = 0` is the "no batching" sentinel: the cursor is fully
72    /// drained and the entire result set is emitted in a single page.
73    #[serde(default = "default_batch_size")]
74    pub batch_size: usize,
75    /// Replication mode. Defaults to [`RedshiftReplication::Full`].
76    #[serde(default)]
77    pub replication: RedshiftReplication,
78    /// Explicit state-store key for the incremental bookmark. When unset, a key
79    /// is derived from the host / database and a query fingerprint.
80    #[serde(default, skip_serializing_if = "Option::is_none")]
81    pub state_key: Option<String>,
82}
83
84impl RedshiftSourceConfig {
85    /// Validate the config; returns a human-readable error if invalid.
86    pub fn validate(&self) -> Result<(), FaucetError> {
87        if self.query.trim().is_empty() {
88            return Err(FaucetError::Config(
89                "redshift: `query` must not be empty".into(),
90            ));
91        }
92        faucet_core::validate_batch_size(self.batch_size)?;
93        let RedshiftReplication::Incremental {
94            column,
95            initial_value,
96        } = &self.replication
97        else {
98            return Ok(());
99        };
100        if column.trim().is_empty() {
101            return Err(FaucetError::Config(
102                "redshift: incremental replication `column` must not be empty".into(),
103            ));
104        }
105        if initial_value.is_null() {
106            return Err(FaucetError::Config(
107                "redshift: incremental replication requires a non-null `initial_value`".into(),
108            ));
109        }
110        if faucet_core::replication::cursor::strict_comparison(&self.query, BOOKMARK_TOKEN) {
111            return Err(FaucetError::Config(format!(
112                "redshift: compare `{BOOKMARK_TOKEN}` with `>=`, not `>`: the source re-reads \
113                 the bookmark value and drops the rows it already emitted, and a strict \
114                 comparison skips rows that share it"
115            )));
116        }
117        Ok(())
118    }
119}
120
121/// The token a query uses to read the incremental bookmark
122/// (`WHERE updated_at >= ${bookmark}`).
123pub const BOOKMARK_TOKEN: &str = "${bookmark}";
124
125#[cfg(test)]
126mod tests;
faucet_source_redshift/config.rs

faucet_source_redshift/
config.rs
