feat: rising fees notification

Dockerfile

@@ -4,5 +4,6 @@ COPY bitcoin-fee-notifier.nu /etc/periodic/hourly/
 ARG NTFY_TOPIC
 ENV NTFY_TOPIC=${NTFY_TOPIC}
 ENV CHEAP_FEE 35
+ENV RISING_TRIGGER 1.5
 ENV NU_LOG_LEVEL DEBUG
 ENTRYPOINT ["crond", "-f"]

README.md

@@ -37,6 +37,18 @@ Example:
 CHEAP_FEE=10
 ```
 
+### RISING_TRIGGER
+
+The percentage (in decimal form) upper limit from the last reported fee to trigger a rising fees notification.
+
+Defaults to `1.5`.
+
+Example:
+
+```
+RISING_TRIGGER=1.618
+```
+
 ## Usage (standalone)
 
 ```bash

bitcoin-fee-notifier.nu

@@ -16,12 +16,17 @@ if not ($last_fee | path exists) {
 let fee = (http get https://mempool.space/api/v1/fees/recommended).economyFee
 let cheap = $env.CHEAP_FEE? | default 35 | into int
 let last = open $last_fee | into int
+let rising_trigger = $env.RISING_TRIGGER? | default 1.5 | into float
 
 if $fee < $cheap {
     if $fee < $last {
         http post --headers [Title 'Cheap transaction fees!' Tags partying_face] $'https://ntfy.sh/($env.NTFY_TOPIC)' $'($fee) sat/vB'
         $fee | save -f $last_fee
         log debug $'Notified cheap transaction fees at ($fee) sat/vB'
+    } else if $fee > $last * $rising_trigger {
+        http post --headers [Title 'Transaction fees rising!' Tags facepalm] $'https://ntfy.sh/($env.NTFY_TOPIC)' $'($fee) sat/vB'
+        $fee | save -f $last_fee
+        log debug $'Notified transaction fees rising to ($fee) sat/vB'
     } else {
         log debug $'Already notified transaction fees at ($fee) sat/vB'
     }