Add postgres-axum example

bikeshedder · bikeshedder · commit 401a0ff56fe4 · 2024-05-07T21:05:58.000+02:00
diff --git a/examples/postgres-axum/Cargo.toml b/examples/postgres-axum/Cargo.toml
@@ -0,0 +1,16 @@
+[package]
+name = "postgres-axum"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+axum = { version = "0.7.5", features = ["json"] }
+thiserror = "1.0.60"
+tokio = { version = "1.37.0", features = ["macros", "rt-multi-thread"] }
+deadpool-postgres = { path = "../../postgres", features = ["serde"] }
+tokio-postgres = { version = "0.7.10", features = ["with-uuid-1"] }
+dotenvy = "0.15.7"
+uuid = { version = "1.8.0", features = ["serde"] }
+serde = { version = "1.0.200", features = ["derive"] }
+config = "0.14.0"
+axum-macros = "0.4.1"
diff --git a/examples/postgres-axum/README.md b/examples/postgres-axum/README.md
@@ -0,0 +1,70 @@
+# `deadpool-postgres` + `axum` example
+
+This example combines `deadpool-postgres` with a `axum` webservice to
+implement a simple API service that responds with JSON read from
+PostgreSQL.
+
+## Running the example
+
+The following instructions assumes that your current user can access the
+PostgreSQL running at local host passwordless via unix domain socket. The
+default installation of PostgreSQL usually already contains the following line
+in its [pg_hba.conf](https://www.postgresql.org/docs/16/auth-pg-hba-conf.html):
+
+```txt
+local all all peer
+```
+
+All you need to do is to create a PostgreSQL user with the same name as
+your system user:
+
+```shell
+sudo -u postgres createuser -s my_user_name
+```
+
+Now create a database
+
+```shell
+createdb deadpool
+```
+
+Now you should be able to connect to the newly created database without
+without any options:
+
+```shell
+psql deadpool
+```
+
+Load example data
+
+```shell
+psql -f fixture.sql deadpool
+```
+
+Create `.env` file in this directory
+
+```env
+LISTEN=[::1]:8000
+PG__DBNAME=deadpool
+```
+
+Run the example
+
+```shell
+cargo run --release
+```
+
+## Configuration options
+
+If you want to connect to your database using a TCP/IP socket you can use
+the following template for your `.env` file:
+
+```env
+PG__HOST=127.0.0.1
+PG__PORT=5432
+PG__USER=deadpool
+PG__PASSWORD=somepassword
+PG__DBNAME=deadpool
+```
+
+For more configuration options see `deadpool_postgres::Config`.
diff --git a/examples/postgres-axum/fixture.sql b/examples/postgres-axum/fixture.sql
@@ -0,0 +1,37 @@
+CREATE EXTENSION IF NOT EXISTS pgcrypto WITH SCHEMA public;
+
+CREATE TABLE event (
+    id uuid DEFAULT public.gen_random_uuid() NOT NULL,
+    title text NOT NULL
+);
+
+COPY event (id, title) FROM stdin;
+bec734be-97bd-4f48-b042-5ee859998c56	event1
+d36bc40a-fac4-4194-bec4-9ba8c602d994	event2
+18012fcf-3c53-4518-b9a6-22479ebe0212	event3
+6c4094fc-f8f7-4869-9c57-042bc43f257d	event4
+e6173a6c-7cf4-4bc5-b676-0871d2705ed6	event5
+0d246195-537f-42dd-b7b3-6495116b8f56	event6
+c6b452b9-c1f3-4e11-9237-e22e0d6f14bd	event7
+33ddb912-5bb1-4ba6-a03c-31a087ca8992	event8
+0da79dbe-63e9-4a0a-a3cb-34cfc451aa7e	event9
+dec2f1cd-01af-41ed-a0d9-83a34a1c7b6d	event10
+ecc1e7e4-828c-4ca3-a8a1-07444bb91300	event11
+c6ca56b1-9e02-4381-a248-3b9ef099eb93	event12
+f94693f0-789a-4a1f-a218-7399c294f00a	event13
+c54ee1d7-2f8c-41c5-9478-a01f4c1c0e0b	event14
+aa213e86-43fe-448d-8862-f2af9c686c82	event15
+7135cb1f-00ee-47be-b212-d45a791082ea	event16
+b7dfa22b-f3a2-4547-a5df-2a6d3f54c90f	event17
+c339d9fd-ce35-4578-a7c5-908cf619a321	event18
+7c49ba99-fdc3-4618-b23b-89ea3e5c4ee4	event19
+499b5807-abd2-4c24-9faa-5f463e6a19e3	event20
+d2ccbdb5-5b1e-4113-aded-24634ba1fb03	event21
+f2c82fc6-5b9a-446a-a6bc-27e814b1521b	event22
+a818fbed-93dd-4e44-84a8-3591dbff3349	event23
+56dd7210-3869-4f1f-9f7a-fc58b3265f63	event24
+5803b0e8-98fe-47cd-b61d-478949b2ad70	event25
+b4a8d7da-ee5f-4d95-b452-86400697d051	event26
+f55fd18a-5532-453c-990e-098df71f2c24	event27
+3938cd54-65cf-4638-aba8-5861d9ba729e	event28
+\.
diff --git a/examples/postgres-axum/src/main.rs b/examples/postgres-axum/src/main.rs
@@ -0,0 +1,88 @@
+use axum::{
+    extract::State,
+    http::StatusCode,
+    response::{IntoResponse, Response},
+    routing::get,
+    Json, Router,
+};
+use axum_macros::debug_handler;
+use config::ConfigError;
+use deadpool_postgres::{Client, Pool, PoolError, Runtime};
+use dotenvy::dotenv;
+use serde::{Deserialize, Serialize};
+use uuid::Uuid;
+
+#[derive(Debug, Deserialize)]
+struct Config {
+    listen: String,
+    pg: deadpool_postgres::Config,
+}
+
+impl Config {
+    pub fn from_env() -> Result<Self, ConfigError> {
+        config::Config::builder()
+            .add_source(config::Environment::default().separator("__"))
+            .build()
+            .unwrap()
+            .try_deserialize()
+    }
+}
+
+#[derive(Deserialize, Serialize)]
+struct Event {
+    id: Uuid,
+    title: String,
+}
+
+#[derive(Debug, thiserror::Error)]
+enum Error {
+    #[error("Pool error: {0}")]
+    PoolError(#[from] PoolError),
+    #[error("PostgreSQL error: {0}")]
+    PgError(#[from] tokio_postgres::Error),
+}
+
+impl IntoResponse for Error {
+    fn into_response(self) -> Response {
+        (
+            StatusCode::INTERNAL_SERVER_ERROR,
+            "An internal error occurred. Please try again later.",
+        )
+            .into_response()
+    }
+}
+
+#[debug_handler]
+async fn event_list(pool: State<Pool>) -> Result<Json<Vec<Event>>, Error> {
+    let client: Client = pool.get().await?;
+    let stmt = client.prepare_cached("SELECT id, title FROM event").await?;
+    let rows = client.query(&stmt, &[]).await?;
+    let events = rows
+        .into_iter()
+        .map(|row| Event {
+            id: row.get(0),
+            title: row.get(1),
+        })
+        .collect::<Vec<_>>();
+    Ok(Json(events))
+}
+
+#[tokio::main]
+async fn main() {
+    dotenv().ok();
+    let config = Config::from_env().unwrap();
+    let pool = config
+        .pg
+        .create_pool(Some(Runtime::Tokio1), tokio_postgres::NoTls)
+        .unwrap();
+    let app = Router::new()
+        .route("/v1.0/event.list", get(event_list))
+        .with_state(pool);
+    let listener = tokio::net::TcpListener::bind(&config.listen).await.unwrap();
+    println!("Server running at http://{}/", &config.listen);
+    println!(
+        "Try the following URLs: http://{}/v1.0/event.list",
+        &config.listen,
+    );
+    axum::serve(listener, app).await.unwrap();
+}
