spin 3 postgres support

Signed-off-by: Michelle Dhanani <michelle@fermyon.com>
Co-authored-by: Brian Hardock <brian.hardock@fermyon.com>

Cargo.toml

@@ -19,6 +19,7 @@ name = "spin_sdk"
 [dependencies]
 anyhow = "1"
 async-trait = "0.1.74"
+chrono = "0.4.38"
 form_urlencoded = "1.0"
 spin-executor = { version = "3.0.1", path = "crates/executor" }
 spin-macro = { version = "3.0.1", path = "crates/macro" }
@@ -52,6 +53,7 @@ members = [
   "examples/key-value",
   "examples/mysql",
   "examples/postgres",
+  "examples/postgres-v3",
   "examples/redis-outbound",
   "examples/mqtt-outbound",
   "examples/variables",

examples/postgres-v3/.cargo/config.toml

@@ -0,0 +1,2 @@
+[build]
+target = "wasm32-wasi"

examples/postgres-v3/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "rust-outbound-pg-v3"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+# Useful crate to handle errors.
+anyhow = "1"
+# General-purpose crate with common HTTP types.
+http = "1.0.0"
+# The Spin SDK.
+spin-sdk = { path = "../.." }
+

examples/postgres-v3/README.md

@@ -0,0 +1,49 @@
+# Spin Outbound PostgreSQL example
+
+This example shows how to access a PostgreSQL database from Spin component.
+
+## Spin up
+
+From example root:
+
+```
+createdb spin_dev
+psql -d spin_dev -f db/testdata.sql
+RUST_LOG=spin=trace spin build --up
+```
+
+Curl the read route:
+
+```
+$ curl -i localhost:3000/read
+HTTP/1.1 200 OK
+content-length: 501
+date: Sun, 25 Sep 2022 15:45:02 GMT
+
+Found 2 article(s) as follows:
+article: Article {
+    id: 1,
+    title: "My Life as a Goat",
+    content: "I went to Nepal to live as a goat, and it was much better than being a butler.",
+    authorname: "E. Blackadder",
+}
+article: Article {
+    id: 2,
+    title: "Magnificent Octopus",
+    content: "Once upon a time there was a lovely little sausage.",
+    authorname: "S. Baldrick",
+}
+
+(Column info: id:DbDataType::Int32, title:DbDataType::Str, content:DbDataType::Str, authorname:DbDataType::Str)
+```
+
+Curl the write route:
+
+```
+$ curl -i localhost:3000/write
+HTTP/1.1 200 OK
+content-length: 9
+date: Sun, 25 Sep 2022 15:46:22 GMT
+
+Count: 3
+```

examples/postgres-v3/db/testdata.sql

@@ -0,0 +1,22 @@
+CREATE TABLE articletest (
+   id integer GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,
+   title varchar(40) NOT NULL,
+   content text NOT NULL,
+   authorname varchar(40) NOT NULL,
+   published date NOT NULL,
+   coauthor text
+);
+
+INSERT INTO articletest (title, content, authorname) VALUES
+(
+   'My Life as a Goat',
+   'I went to Nepal to live as a goat, and it was much better than being a butler.',
+   'E. Blackadder'
+   '2024-11-05'
+),
+(
+   'Magnificent Octopus',
+   'Once upon a time there was a lovely little sausage.',
+   'S. Baldrick'
+   '2024-11-06'
+);

examples/postgres-v3/spin.toml

@@ -0,0 +1,17 @@
+spin_manifest_version = 2
+
+[application]
+authors = ["Fermyon Engineering <engineering@fermyon.com>"]
+name = "rust-outbound-pg-v3-example"
+version = "0.1.0"
+
+[[trigger.http]]
+route = "/..."
+component = "outbound-pg"
+
+[component.outbound-pg]
+environment = { DB_URL = "host=localhost user=postgres dbname=spin_dev" }
+source = "../../target/wasm32-wasi/release/rust_outbound_pg.wasm"
+allowed_outbound_hosts = ["postgres://localhost"]
+[component.outbound-pg.build]
+command = "cargo build --target wasm32-wasi --release"

examples/postgres-v3/src/lib.rs

@@ -0,0 +1,132 @@
+#![allow(dead_code)]
+use anyhow::Result;
+use http::{Request, Response};
+use spin_sdk::{
+    http_component,
+    pg3::{Date, Decode},
+};
+
+// The environment variable set in `spin.toml` that points to the
+// address of the Pg server that the component will write to
+const DB_URL_ENV: &str = "DB_URL";
+
+#[derive(Debug, Clone)]
+struct Article {
+    id: i32,
+    title: String,
+    content: String,
+    authorname: String,
+    published: Date,
+    coauthor: Option<String>,
+}
+
+impl TryFrom<&pg::Row> for Article {
+    type Error = anyhow::Error;
+
+    fn try_from(row: &pg::Row) -> Result<Self, Self::Error> {
+        let id = i32::decode(&row[0])?;
+        let title = String::decode(&row[1])?;
+        let content = String::decode(&row[2])?;
+        let authorname = String::decode(&row[3])?;
+        let published = Date::decode(&row[4])?;
+        let coauthor = Option::<String>::decode(&row[5])?;
+
+        Ok(Self {
+            id,
+            title,
+            content,
+            authorname,
+            published,
+            coauthor,
+        })
+    }
+}
+
+#[http_component]
+fn process(req: Request<()>) -> Result<Response<String>> {
+    match req.uri().path() {
+        "/read" => read(req),
+        "/write" => write(req),
+        "/pg_backend_pid" => pg_backend_pid(req),
+        _ => Ok(http::Response::builder()
+            .status(404)
+            .body("Not found".into())?),
+    }
+}
+
+fn read(_req: Request<()>) -> Result<Response<String>> {
+    let address = std::env::var(DB_URL_ENV)?;
+    let conn = pg::Connection::open(&address)?;
+
+    let sql = "SELECT id, title, content, authorname, coauthor FROM articletest";
+    let rowset = conn.query(sql, &[])?;
+
+    let column_summary = rowset
+        .columns
+        .iter()
+        .map(format_col)
+        .collect::<Vec<_>>()
+        .join(", ");
+
+    let mut response_lines = vec![];
+
+    for row in rowset.rows {
+        let article = Article::try_from(&row)?;
+
+        println!("article: {:#?}", article);
+        response_lines.push(format!("article: {:#?}", article));
+    }
+
+    // use it in business logic
+
+    let response = format!(
+        "Found {} article(s) as follows:\n{}\n\n(Column info: {})\n",
+        response_lines.len(),
+        response_lines.join("\n"),
+        column_summary,
+    );
+
+    Ok(http::Response::builder().status(200).body(response)?)
+}
+
+fn write(_req: Request<()>) -> Result<Response<String>> {
+    let address = std::env::var(DB_URL_ENV)?;
+    let conn = pg::Connection::open(&address)?;
+
+    let sql =
+        "INSERT INTO articletest (title, content, authorname, published) VALUES ('aaa', 'bbb', 'ccc', '2024-01-01')";
+    let nrow_executed = conn.execute(sql, &[])?;
+
+    println!("nrow_executed: {}", nrow_executed);
+
+    let sql = "SELECT COUNT(id) FROM articletest";
+    let rowset = conn.query(sql, &[])?;
+    let row = &rowset.rows[0];
+    let count = i64::decode(&row[0])?;
+    let response = format!("Count: {}\n", count);
+
+    Ok(http::Response::builder().status(200).body(response)?)
+}
+
+fn pg_backend_pid(_req: Request<()>) -> Result<Response<String>> {
+    let address = std::env::var(DB_URL_ENV)?;
+    let conn = pg::Connection::open(&address)?;
+    let sql = "SELECT pg_backend_pid()";
+
+    let get_pid = || {
+        let rowset = conn.query(sql, &[])?;
+        let row = &rowset.rows[0];
+
+        i32::decode(&row[0])
+    };
+
+    assert_eq!(get_pid()?, get_pid()?);
+
+    let response = format!("pg_backend_pid: {}\n", get_pid()?);
+
+    Ok(http::Response::builder().status(200).body(response)?)
+}
+
+fn format_col(column: &pg::Column) -> String {
+    format!("{}:{:?}", column.name, column.data_type)
+}

src/lib.rs

@@ -34,6 +34,7 @@ pub mod wit {
         }
     });
     pub use fermyon::spin2_0_0 as v2;
+    pub use spin::postgres::postgres as pg3;
 }
 
 /// Needed by the export macro
@@ -101,6 +102,9 @@ pub mod redis {
 /// Implementation of the spin postgres db interface.
 pub mod pg;
 
+/// Implementation of the spin postgres v3 db interface.
+pub mod pg3;
+
 /// Implementation of the Spin MySQL database interface.
 pub mod mysql;