Add Gotify notification support to ZED

This commit adds the zed_notify_gotify() function and hooks it
into zed_notify(). This will allow ZED to send notifications
to a self-hosted Gotify service, which can be received
on a desktop or mobile device. It is configured with ZED_GOTIFY_URL,
ZED_GOTIFY_APPTOKEN and ZED_GOTIFY_PRIORITY variables in zed.rc.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: gofaster <felix.gofaster@gmail.com>
Closes #15693

cmd/zed/zed.d/zed-functions.sh

@@ -209,6 +209,10 @@ zed_notify()
     [ "${rv}" -eq 0 ] && num_success=$((num_success + 1))
     [ "${rv}" -eq 1 ] && num_failure=$((num_failure + 1))
 
+    zed_notify_gotify "${subject}" "${pathname}"; rv=$?
+    [ "${rv}" -eq 0 ] && num_success=$((num_success + 1))
+    [ "${rv}" -eq 1 ] && num_failure=$((num_failure + 1))
+
     [ "${num_success}" -gt 0 ] && return 0
     [ "${num_failure}" -gt 0 ] && return 1
     return 2
@@ -624,6 +628,97 @@ zed_notify_ntfy()
 }
 
 
+# zed_notify_gotify (subject, pathname)
+#
+# Send a notification via Gotify <https://gotify.net/>.
+# The Gotify URL (ZED_GOTIFY_URL) defines a self-hosted Gotify location.
+# The Gotify application token (ZED_GOTIFY_APPTOKEN) defines a
+# Gotify application token which is associated with a message.
+# The optional Gotify priority value (ZED_GOTIFY_PRIORITY) overrides the
+# default or configured priority at the Gotify server for the application.
+#
+# Requires curl and sed executables to be installed in the standard PATH.
+#
+# References
+#   https://gotify.net/docs/index
+#
+# Arguments
+#   subject: notification subject
+#   pathname: pathname containing the notification message (OPTIONAL)
+#
+# Globals
+#   ZED_GOTIFY_URL
+#   ZED_GOTIFY_APPTOKEN
+#   ZED_GOTIFY_PRIORITY
+#
+# Return
+#   0: notification sent
+#   1: notification failed
+#   2: not configured
+#
+zed_notify_gotify()
+{
+    local subject="$1"
+    local pathname="${2:-"/dev/null"}"
+    local msg_body
+    local msg_out
+    local msg_err
+
+    [ -n "${ZED_GOTIFY_URL}" ] && [ -n "${ZED_GOTIFY_APPTOKEN}" ] || return 2
+    local url="${ZED_GOTIFY_URL}/message?token=${ZED_GOTIFY_APPTOKEN}"
+
+    if [ ! -r "${pathname}" ]; then
+        zed_log_err "gotify cannot read \"${pathname}\""
+        return 1
+    fi
+
+    zed_check_cmd "curl" "sed" || return 1
+
+    # Read the message body in.
+    #
+    msg_body="$(cat "${pathname}")"
+
+    if [ -z "${msg_body}" ]
+    then
+        msg_body=$subject
+        subject=""
+    fi
+
+    # Send the POST request and check for errors.
+    #
+    if [ -n "${ZED_GOTIFY_PRIORITY}" ]; then
+        msg_out="$( \
+        curl \
+        --form-string "title=${subject}" \
+        --form-string "message=${msg_body}" \
+        --form-string "priority=${ZED_GOTIFY_PRIORITY}" \
+        "${url}" \
+        2>/dev/null \
+        )"; rv=$?
+    else
+        msg_out="$( \
+        curl \
+        --form-string "title=${subject}" \
+        --form-string "message=${msg_body}" \
+        "${url}" \
+        2>/dev/null \
+        )"; rv=$?
+    fi
+
+    if [ "${rv}" -ne 0 ]; then
+        zed_log_err "curl exit=${rv}"
+        return 1
+    fi
+    msg_err="$(echo "${msg_out}" \
+        | sed -n -e 's/.*"errors" *:.*\[\(.*\)\].*/\1/p')"
+    if [ -n "${msg_err}" ]; then
+        zed_log_err "gotify \"${msg_err}"\"
+        return 1
+    fi
+    return 0
+}
+
+
 
 # zed_rate_limit (tag, [interval])
 #

cmd/zed/zed.d/zed.rc

@@ -169,3 +169,24 @@ ZED_SYSLOG_SUBCLASS_EXCLUDE="history_event"
 #  <https://docs.ntfy.sh/install/>
 # https://ntfy.sh by default; uncomment to enable an alternative service url.
 #ZED_NTFY_URL="https://ntfy.sh"
+
+##
+# Gotify server URL
+# This defines a URL that the Gotify call will be directed toward.
+# <https://gotify.net/docs/index>
+# Disabled by default; uncomment to enable.
+#ZED_GOTIFY_URL=""
+
+##
+# Gotify application token
+# This defines a Gotify application token which a message is associated with.
+# This token is generated when an application is created on the Gotify server.
+# Disabled by default; uncomment to enable.
+#ZED_GOTIFY_APPTOKEN=""
+
+##
+# Gotify priority (optional)
+# If defined, this overrides the default priority of the
+# Gotify application associated with ZED_GOTIFY_APPTOKEN.
+# Value is an integer 0 and up.
+#ZED_GOTIFY_PRIORITY=""