init

.gitignore

@@ -0,0 +1,2 @@
+/target
+.env

.gitlab-ci.yml

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+variables:
+  DOCKER_TLS_CERTDIR: ""
+  DOCKER_HOST: tcp://docker:2375
+
+services:
+  - name: docker:dind
+    entrypoint: ["dockerd-entrypoint.sh", "--tls=false"]
+
+stages:
+  - build
+    #  - test
+  - pack
+
+cargo-build:
+  stage: build
+  image: rust:slim
+  variables:
+    CARGO_HOME: $CI_PROJECT_DIR/.cargo
+  before_script:
+  script:
+    - cargo build --release
+  cache:
+    key: $CI_COMMIT_REF_SLUG
+    paths:
+      - target/
+      - .cargo/registry/index/
+      - .cargo/registry/cache/
+  artifacts:
+    paths:
+      - target/release/bin
+
+docker:
+  stage: pack
+  image: docker:latest
+  only:
+    - master
+  script:
+    - docker login -u gitlab-ci-token -p $CI_JOB_TOKEN $CI_REGISTRY
+    - docker build --network host -t $CI_REGISTRY_IMAGE/master . -f Dockerfile
+    - docker push $CI_REGISTRY_IMAGE/master
+  dependencies:
+    - cargo-build

Cargo.toml

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+[package]
+name = "stromsensor_mailer"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+dotenvy = "0.15.7"
+sqlx = { version = "0.6", features = ["runtime-tokio-rustls", "mysql", "chrono", "decimal"], default-features=false }
+lettre = { version="0.10.4", features=["smtp-transport", "pool", "rustls-tls", "hostname", "builder"], default-features=false }
+tokio = { version = "1.28.0", features = ["full"] }
+chrono = "0.4.24"
+rust_decimal = "1.29.1"

Dockerfile

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+
+FROM debian:stable-slim as final
+WORKDIR /app
+COPY ./target/release/bin ./bin
+CMD ["/app/bin"]

src/main.rs

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+use std::env;
+
+use chrono::{Local, NaiveDateTime};
+use lettre::{
+    message::header::ContentType, transport::smtp::authentication::Credentials, Message,
+    SmtpTransport, Transport,
+};
+use rust_decimal::{prelude::ToPrimitive, Decimal};
+use sqlx::{Connection, MySqlConnection, Row};
+
+#[tokio::main]
+async fn main() {
+    dotenvy::dotenv().ok();
+    let mut connection = MySqlConnection::connect(
+        &env::var("DATABASE_URL").expect("DATABASE_URL environment variable"),
+    )
+    .await
+    .unwrap();
+
+    let email_host = env::var("EMAIL_HOST").expect("EMAIL_HOST env var");
+    let email_user = env::var("EMAIL_USER").expect("EMAIL_USER env var");
+    let email_pass = env::var("EMAIL_PASS").expect("EMAIL_PASS env var");
+    let email_name = env::var("EMAIL_NAME").expect("EMAIL_NAME env var");
+    let email_to = env::var("EMAIL_TO").expect("EMAIL_TO env var");
+
+    let row =
+        sqlx::query("SELECT timestamp, value FROM counter_value ORDER BY timestamp DESC LIMIT 1")
+            .fetch_one(&mut connection)
+            .await
+            .unwrap();
+
+    let timestamp: NaiveDateTime = row.get("timestamp");
+    let value: Decimal = row.get("value");
+
+    let now = Local::now();
+
+    let mut email =
+        Message::builder().from(format!("{email_name} <{email_user}>").parse().unwrap());
+    for to in email_to.split(',') {
+        email = email.to(to.parse().unwrap());
+    }
+    let email = email
+        .subject(format!("Zählerstand vom {}", now.format("%d.%m.%Y")))
+        .header(ContentType::TEXT_PLAIN)
+        .body(format!(
+            "Zählerstand: {:.3} kWh\nStand: {} UTC",
+            (value.to_u128().unwrap() as f64) / 1000.0,
+            timestamp.format("%d.%m.%Y %H:%m"),
+        ))
+        .unwrap();
+
+    let creds = Credentials::new(email_user, email_pass);
+
+    SmtpTransport::relay(&email_host)
+        .unwrap()
+        .credentials(creds)
+        .build()
+        .send(&email)
+        .unwrap();
+}