bot: watch journald and send events

Cargo.lock

@@ -130,9 +130,11 @@ version = "0.1.0"
 dependencies = [
  "anyhow",
  "clap",
+ "futures",
  "matrix-sdk",
  "serde",
  "serde_yaml",
+ "systemd",
  "thiserror",
  "tokio",
  "tracing-subscriber",
@@ -166,6 +168,12 @@ dependencies = [
  "generic-array",
 ]
 
+[[package]]
+name = "build-env"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6cf89846ef2b2674ef1c153256cec98fba587c72bf4ea2c4b2f6d91a19f55926"
+
 [[package]]
 name = "bumpalo"
 version = "3.6.0"
@@ -190,6 +198,12 @@ version = "1.0.66"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4c0496836a84f8d0495758516b8621a622beb77c0fed418570e50764093ced48"
 
+[[package]]
+name = "cfg-if"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
+
 [[package]]
 name = "cfg-if"
 version = "1.0.0"
@@ -322,7 +336,7 @@ version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "81156fece84ab6a9f2afdb109ce3ae577e42b1228441eded99bd77f627953b1a"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
 ]
 
 [[package]]
@@ -331,7 +345,7 @@ version = "0.9.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a1aaa739f95311c2c7887a76863f500026092fb1dce0161dab577e559ef3569d"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
  "const_fn",
  "crossbeam-utils",
  "lazy_static",
@@ -346,7 +360,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "02d96d1e189ef58269ebe5b97953da3274d83a93af647c2ddd6f9dab28cedb8d"
 dependencies = [
  "autocfg",
- "cfg-if",
+ "cfg-if 1.0.0",
  "lazy_static",
 ]
 
@@ -360,6 +374,16 @@ dependencies = [
  "subtle",
 ]
 
+[[package]]
+name = "cstr-argument"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "20bd4e8067c20c7c3a4dea759ef91d4b18418ddb5bd8837ef6e2f2f93ca7ccbb"
+dependencies = [
+ "cfg-if 0.1.10",
+ "memchr",
+]
+
 [[package]]
 name = "ctr"
 version = "0.6.0"
@@ -375,7 +399,7 @@ version = "4.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e77a43b28d0668df09411cb0bc9a8c2adc40f9a048afe863e05fd43251e8e39c"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
  "num_cpus",
 ]
 
@@ -406,7 +430,7 @@ version = "0.8.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "801bbab217d7f79c0062f4f7205b5d4427c6d1a7bd7aafdd1475f7c59d62b283"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
 ]
 
 [[package]]
@@ -421,7 +445,28 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f6f339eb8adc052cd2ca78910fda869aefa38d22d5cb648e6485e4d3fc06f3b1"
 dependencies = [
- "foreign-types-shared",
+ "foreign-types-shared 0.1.1",
+]
+
+[[package]]
+name = "foreign-types"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d737d9aa519fb7b749cbc3b962edcf310a8dd1f4b67c91c4f83975dbdd17d965"
+dependencies = [
+ "foreign-types-macros",
+ "foreign-types-shared 0.3.0",
+]
+
+[[package]]
+name = "foreign-types-macros"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "63f713f8b2aa9e24fec85b0e290c56caee12e3b6ae0aeeda238a75b28251afd6"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
 ]
 
 [[package]]
@@ -430,6 +475,12 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "00b0228411908ca8685dba7fc2cdd70ec9990a6e753e89b6ac91a84c40fbaf4b"
 
+[[package]]
+name = "foreign-types-shared"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7684cf33bb7f28497939e8c7cf17e3e4e3b8d9a0080ffa4f8ae2f515442ee855"
+
 [[package]]
 name = "form_urlencoded"
 version = "1.0.0"
@@ -589,7 +640,7 @@ version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c9495705279e7140bf035dde1f6e750c162df8b625267cd52cc44e0b156732c8"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
  "js-sys",
  "libc",
  "wasi",
@@ -770,7 +821,7 @@ version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "61124eeebbd69b8190558df225adf7e4caafce0d743919e5d6b19652314ec5ec"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
  "js-sys",
  "time 0.2.25",
  "wasm-bindgen",
@@ -819,6 +870,17 @@ version = "0.2.84"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1cca32fa0182e8c0989459524dc356b8f2b5c10f1b9eb521b7d182c03cf8c5ff"
 
+[[package]]
+name = "libsystemd-sys"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6e03fd580bcecda68dcdcd5297085ade6a3dc552cd8b030d2b94a9b089ef7ab8"
+dependencies = [
+ "build-env",
+ "libc",
+ "pkg-config",
+]
+
 [[package]]
 name = "linked-hash-map"
 version = "0.5.4"
@@ -840,7 +902,7 @@ version = "0.4.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "51b9bbe6c47d51fc3e1a9b945965946b4c44142ab8792c50835a980d362c2710"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
 ]
 
 [[package]]
@@ -1089,8 +1151,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "038d43985d1ddca7a9900630d8cd031b56e4794eecc2e9ea39dd17aa04399a70"
 dependencies = [
  "bitflags",
- "cfg-if",
+ "cfg-if 1.0.0",
- "foreign-types",
+ "foreign-types 0.3.2",
  "lazy_static",
  "libc",
  "openssl-sys",
@@ -1138,7 +1200,7 @@ version = "0.8.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9ccb628cad4f84851442432c60ad8e1f607e29752d0bf072cbd0baf28aa34272"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
  "instant",
  "libc",
  "redox_syscall 0.1.57",
@@ -1748,7 +1810,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fa827a14b29ab7f44778d14a88d3cb76e949c45083f7dbfa507d0cb699dc12de"
 dependencies = [
  "block-buffer",
- "cfg-if",
+ "cfg-if 1.0.0",
  "cpuid-bool 0.1.2",
  "digest",
  "opaque-debug",
@@ -1806,7 +1868,7 @@ version = "0.3.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "122e570113d28d773067fab24266b66753f6ea915758651696b6e35e49f88d6e"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
  "libc",
  "winapi",
 ]
@@ -1904,13 +1966,28 @@ dependencies = [
  "unicode-xid",
 ]
 
+[[package]]
+name = "systemd"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f722cabda922e471742300045f56dbaa53fafbb4520fca304e51258019bfe91d"
+dependencies = [
+ "cstr-argument",
+ "foreign-types 0.5.0",
+ "libc",
+ "libsystemd-sys",
+ "log",
+ "memchr",
+ "utf8-cstr",
+]
+
 [[package]]
 name = "tempfile"
 version = "3.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dac1c663cfc93810f88aed9b8941d48cabf856a1b111c29a40439018d870eb22"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
  "libc",
  "rand",
  "redox_syscall 0.2.4",
@@ -2104,7 +2181,7 @@ version = "0.1.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9f47026cdc4080c07e49b37087de021820269d996f581aac150ef9e5583eefe3"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
  "pin-project-lite",
  "tracing-attributes",
  "tracing-core",
@@ -2254,6 +2331,12 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "utf8-cstr"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "55bcbb425141152b10d5693095950b51c3745d019363fc2929ffd8f61449b628"
+
 [[package]]
 name = "uuid"
 version = "0.8.2"
@@ -2304,7 +2387,7 @@ version = "0.2.70"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "55c0f7123de74f0dab9b7d00fd614e7b19349cd1e2f5252bbe9b1754b59433be"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
  "serde",
  "serde_json",
  "wasm-bindgen-macro",
@@ -2331,7 +2414,7 @@ version = "0.4.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3de431a2910c86679c34283a33f66f4e4abd7e0aec27b6669060148872aadf94"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
  "js-sys",
  "wasm-bindgen",
  "web-sys",

Cargo.toml

@@ -9,11 +9,13 @@ edition = "2018"
 [dependencies]
 anyhow = "1.0"
 clap = "3.0.0-beta.2"
+futures = "0.3"
 tokio = { version = "1", features = [ "full" ] }
 tracing-subscriber = "0.2"
 url = { version = "2.2", features = [ "serde" ] }
 serde_yaml = "0.8"
 serde = "1.0"
+systemd = "0.8"
 thiserror = "1.0"
 
 [dependencies.matrix-sdk]

src/bot.rs

@@ -3,11 +3,19 @@ use std::{
     io::{BufReader, BufWriter},
 };
 
-use matrix_sdk::{Client, ClientConfig, Session, SyncSettings};
+use matrix_sdk::{
+    events::{
+        room::message::{MessageEventContent, TextMessageEventContent},
+        AnyMessageEventContent,
+    },
+    Client, ClientConfig, Session, SyncSettings,
+};
+use systemd::{journal, JournalRecord};
 
 use crate::autojoin::AutoJoinHandler;
 use crate::Config;
 
+#[derive(Clone)]
 pub struct BadNewsBot {
     client: Client,
     config: Config,
@@ -46,8 +54,76 @@ impl BadNewsBot {
     /// [`BadNewsBot::init`] **must** be called before this function, otherwise the [`Client`] isn't
     /// logged in.
     pub async fn run(&self) {
+        let clone = self.clone();
+
+        tokio::task::spawn_blocking(move || clone.watch_journald());
+
         self.client.sync(SyncSettings::default()).await
     }
+
+    fn watch_journald(&self) {
+        let mut reader = journal::OpenOptions::default()
+            .system(true)
+            .open()
+            .expect("Could not open journal");
+
+        // Seek to end of current log to prevent old messages from being printed
+        reader
+            .seek_tail()
+            .expect("Could not seek to end of journal");
+
+        // HACK: for some reason calling `seek_tail` above still leaves old entries when calling
+        // next, so skip all those before we start the real logging
+        loop {
+            if reader.next().unwrap() == 0 {
+                break;
+            }
+        }
+
+        // NOTE: Ugly double loop, but low level `wait` has to be used if we don't want to miss any
+        // new entry. See https://github.com/jmesmon/rust-systemd/issues/66
+        loop {
+            loop {
+                let record = reader.next_entry().unwrap();
+                match record {
+                    Some(record) => self.handle_record(record),
+                    None => break,
+                }
+            }
+
+            reader.wait(None).unwrap();
+        }
+    }
+
+    fn handle_record(&self, record: JournalRecord) {
+        const KEY_UNIT: &str = "_SYSTEMD_UNIT";
+        const KEY_MESSAGE: &str = "MESSAGE";
+
+        if let Some(unit) = record.get(KEY_UNIT) {
+            if !self.config.units.contains(unit) {
+                return;
+            }
+
+            let message = record.get(KEY_MESSAGE);
+            let message = format!(
+                "[{}] {}",
+                unit.strip_suffix(".service").unwrap_or(unit),
+                message.map(|m| m.as_ref()).unwrap_or("<EMPTY MESSAGE>")
+            );
+            let content = AnyMessageEventContent::RoomMessage(MessageEventContent::Text(
+                TextMessageEventContent::plain(message),
+            ));
+            let room_id = self.config.room_id.clone();
+            let client_clone = self.client.clone();
+
+            tokio::spawn(async move {
+                client_clone
+                    .room_send(&room_id, content, None)
+                    .await
+                    .unwrap();
+            });
+        }
+    }
 }
 
 /// This loads the session information from an existing file, and tries to login with it. If no such

src/main.rs

@@ -1,4 +1,5 @@
 use std::{
+    collections::HashSet,
     fs::File,
     io::{self, BufReader},
     path::PathBuf,
@@ -32,7 +33,7 @@ struct Opts {
 }
 
 /// Holds the configuration for the bot.
-#[derive(Deserialize)]
+#[derive(Clone, Deserialize)]
 pub struct Config {
     /// The URL for the homeserver we should connect to
     homeserver: Url,
@@ -45,6 +46,8 @@ pub struct Config {
     /// ID of the Matrix room where the bot should post messages. The bot will only accept
     /// invitations to this room.
     room_id: RoomId,
+    /// Units to watch for logs
+    units: HashSet<String>,
 }
 
 #[tokio::main]