feat: add ability to set a custom priority for traefik routing rules

docs/networking/proxies/traefik.md

@@ -112,7 +112,17 @@ Traefik log output is set to `ERROR` by default. It may be changed by setting th
 dokku traefik:set --global log-level DEBUG
 ```
 
-After modifying,  the Traefik container will need to be restarted.
+After modifying, the Traefik container will need to be restarted.
+
+### Setting rule priority
+
+By default, app deployments will result in the newer traefik rules using a higher priority in order to have any newer rules respected by Traefik. Rule priorities will always increase according to the current unix timestamp. The priority may be fixed by setting the app-level `priority` property:
+
+```shell
+dokku traefik:set node-js-app priority 12345
+```
+
+After modifying, the app container will need to be recreated via a `ps:rebuild` or an app deployment.
 
 ### SSL Configuration
 

plugins/traefik-vhosts/command-functions

@@ -44,6 +44,7 @@ cmd-traefik-report-single() {
     "--traefik-letsencrypt-email: $(fn-traefik-letsencrypt-email)"
     "--traefik-letsencrypt-server: $(fn-traefik-letsencrypt-server)"
     "--traefik-log-level: $(fn-traefik-log-level)"
+    "--traefik-priority: $(fn-traefik-priority "$APP")"
   )
 
   if [[ -z "$INFO_FLAG" ]]; then

plugins/traefik-vhosts/docker-args-process-deploy

@@ -1,5 +1,6 @@
 #!/usr/bin/env bash
 source "$PLUGIN_CORE_AVAILABLE_PATH/common/functions"
+source "$PLUGIN_AVAILABLE_PATH/traefik-vhosts/internal-functions"
 set -eo pipefail
 [[ $DOKKU_TRACE ]] && set -x
 
@@ -81,7 +82,10 @@ trigger-traefik-vhosts-docker-args-process-deploy() {
       traefik_domains="${traefik_domains// /\\\`,\\\`}"
     fi
 
-    priority="$(date +%s)"
+    priority="$(fn-traefik-priority "$APP")"
+    if [[ -z "$priority" ]]; then
+      priority="$(date +%s)"
+    fi
 
     output="--label traefik.enable=true"
     if [[ -n "$proxy_container_http_port" ]] || [[ -n "$proxy_container_http_port_candidate" ]]; then

plugins/traefik-vhosts/internal-functions

@@ -92,3 +92,8 @@ fn-traefik-log-level() {
   log_level="$(fn-plugin-property-get-default "traefik" "--global" "log-level" "ERROR")"
   echo "${log_level^^}"
 }
+
+fn-traefik-priority() {
+  declare APP="$1"
+  fn-plugin-property-get-default "traefik" "$APP" "priority" ""
+}

plugins/traefik-vhosts/post-delete

@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+source "$PLUGIN_CORE_AVAILABLE_PATH/common/property-functions"
+set -eo pipefail
+[[ $DOKKU_TRACE ]] && set -x
+
+trigger-traefik-vhosts-post-delete() {
+  declare desc="traefik-vhosts post-delete trigger"
+  declare trigger="post-delete"
+  declare APP="$1"
+
+  fn-plugin-property-destroy "traefik" "$APP"
+}
+
+trigger-traefik-vhosts-post-delete "$@"

plugins/traefik-vhosts/subcommands/set

@@ -9,13 +9,13 @@ cmd-traefik-set() {
   declare cmd="traefik:set"
   [[ "$1" == "$cmd" ]] && shift 1
   declare APP="$1" KEY="$2" VALUE="$3"
-  local VALID_KEYS=("api-enabled" "api-vhost" "dashboard-enabled" "basic-auth-username" "basic-auth-password" "image" "letsencrypt-email" "log-level")
-  local GLOBAL_KEYS=("api-enabled" "api-vhost" "dashboard"-enabled "basic-auth-username" "basic-auth-password" "image" "letsencrypt-email" "log-level")
+  local VALID_KEYS=("api-enabled" "api-vhost" "dashboard-enabled" "basic-auth-username" "basic-auth-password" "image" "letsencrypt-email" "letsencrypt-server" "log-level" "priority")
+  local GLOBAL_KEYS=("api-enabled" "api-vhost" "dashboard"-enabled "basic-auth-username" "basic-auth-password" "image" "letsencrypt-email" "letsencrypt-server" "log-level")
 
   [[ -z "$KEY" ]] && dokku_log_fail "No key specified"
 
   if ! fn-in-array "$KEY" "${VALID_KEYS[@]}"; then
-    dokku_log_fail "Invalid key specified, valid keys include: api-enabled api-vhost dashboard-enabled basic-auth-username basic-auth-password image letsencrypt-email log-level"
+    dokku_log_fail "Invalid key specified, valid keys include: api-enabled api-vhost dashboard-enabled basic-auth-username basic-auth-password image letsencrypt-email letsencrypt-server log-level priority"
   fi
 
   if ! fn-in-array "$KEY" "${GLOBAL_KEYS[@]}"; then

tests/unit/traefik.bats

@@ -81,3 +81,25 @@ teardown() {
   assert_success
   assert_output "python/http.server"
 }
+
+@test "(traefik) traefik:set priority" {
+  run /bin/bash -c "dokku proxy:set $TEST_APP traefik"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+
+  run /bin/bash -c "dokku traefik:set $TEST_APP priority 12345"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+
+  run deploy_app
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+
+  run /bin/bash -c "docker inspect $TEST_APP.web.1 --format '{{ index .Config.Labels \"traefik.http.services.$TEST_APP-web-http-12345.loadbalancer.server.port\" }}'"
+  echo "output: $output"
+  echo "status: $status"
+  assert_output "5000"
+}