feat(telegram): add code block escaping for Telegram messages

src/phoenix/alerts/telegram.rs

@@ -16,8 +16,8 @@ pub static BUILDER_ID_CHANNEL_ID_MAP: LazyLock<HashMap<String, String>> = LazyLo
     .collect()
 });
 
-// Used to escape characters in telegram messages.
-// https://core.telegram.org/bots/api#markdownv2-style
+/// Used to escape characters in telegram messages.
+/// https://core.telegram.org/bots/api#markdownv2-style
 pub fn escape_str(input: &str) -> String {
     let mut output = String::new();
     for c in input.chars() {
@@ -33,6 +33,20 @@ pub fn escape_str(input: &str) -> String {
     output
 }
 
+/// Inside a ``` code block, we need to escape only backticks and backslashes.
+/// https://core.telegram.org/bots/api#markdownv2-style
+pub fn escape_code_block(input: &str) -> String {
+    let mut output: String = String::new();
+    for c in input.chars() {
+        match c {
+            '`' => output.push_str("\\`"),
+            '\\' => output.push_str("\\\\"),
+            _ => output.push(c),
+        }
+    }
+    output
+}
+
 /// Formats a message to be compatible with the Telegram bot API.
 /// Respect escaping as described in: https://core.telegram.org/bots/api#markdownv2-style
 /// Respect character limit of 4096.

src/phoenix/demotion_monitor.rs

@@ -120,12 +120,14 @@ fn filter_demotions(demotions: Vec<BuilderDemotion>) -> Vec<BuilderDemotion> {
         .collect_vec()
 }
 
+// this fn sometimes produces a message telegram doesn't like.
+// our current attempt to fix this is to escape the code block.
 fn format_demotion_message(demotion: &BuilderDemotion) -> String {
     let explorer_url = APP_CONFIG.network.to_beacon_explorer_url();
     let builder_id = demotion.builder_id.as_deref().unwrap_or("unknown");
     let escaped_builder_id = telegram::escape_str(builder_id);
     let builder_pubkey = &demotion.builder_pubkey;
-    let error = telegram::escape_str(&demotion.sim_error);
+    let error = telegram::escape_code_block(&demotion.sim_error);
     let slot = &demotion.slot;
     let geo = &demotion.geo;
     let block_hash = &demotion.block_hash;