feat(rails): support multi-database aliases (#13368)

Rails applications can define more than one database (`primary`, `cache`, `cable`, `queue`, ...), and each one gets its own namespaced task. These commands accept an optional database name as the first argument:

`rdc`, `rdd`, `rdm`, `rdmd`, `rdmr`, `rdms`, `rdmu`, `rdr`, `rdrs`, `rdsl`

Co-authored-by: Robby Russell <robby@planetargon.com>

plugins/rails/README.md

@@ -54,6 +54,33 @@ plugins=(... rails)
 | `rta`   | `rails test:all`                 | Runs all Rails tests, including system tests           |
 | `ru`    | `rails runner`                   | Run Ruby code in the context of Rails                  |
 
+### Multiple databases
+
+Rails applications can define more than one database (`primary`, `cache`, `cable`,
+`queue`, ...), and each one gets its own namespaced task. These commands accept an
+optional database name as the first argument:
+
+`rdc`, `rdd`, `rdm`, `rdmd`, `rdmr`, `rdms`, `rdmu`, `rdr`, `rdrs`, `rdsl`
+
+```zsh
+rdm                    # rails db:migrate
+rdm cache              # rails db:migrate:cache
+rdm VERSION=20231225   # rails db:migrate VERSION=20231225
+rdm cache STEP=2       # rails db:migrate:cache STEP=2
+rdm --trace            # rails db:migrate --trace
+```
+
+The first argument is read as a database name only when it is a bare word. Flags
+(`--trace`), variables (`STEP=2`) and other tasks (`db:seed`) are passed through to
+`rails` unchanged, so previous usage keeps working. When a database name is given,
+the resolved command is printed so it is clear which database is being used.
+
+`rdmrs` is not in the list above because Rails does not define a per-database
+`db:migrate:reset` task.
+
+Note that these are implemented as shell functions rather than aliases, so they will
+not appear in the output of `alias`.
+
 ### Foreman
 
 | Alias  | Command         | Description                               |

plugins/rails/rails.plugin.zsh

@@ -47,19 +47,9 @@ alias rc='rails console'
 alias rcs='rails console --sandbox'
 alias rd='rails destroy'
 alias rdb='rails dbconsole'
-alias rdc='rails db:create'
-alias rdd='rails db:drop'
-alias rdm='rails db:migrate'
-alias rdmd='rails db:migrate:down'
-alias rdmr='rails db:migrate:redo'
 alias rdmrs='rails db:migrate:reset'
-alias rdms='rails db:migrate:status'
 alias rdmtc='rails db:migrate db:test:clone'
-alias rdmu='rails db:migrate:up'
-alias rdr='rails db:rollback'
-alias rdrs='rails db:reset'
 alias rds='rails db:seed'
-alias rdsl='rails db:schema:load'
 alias rdtc='rails db:test:clone'
 alias rdtp='rails db:test:prepare'
 alias rgen='rails generate'
@@ -106,6 +96,47 @@ alias rkn='rake notes'
 alias rksts='rake stats'
 alias rkt='rake test'
 
+# Database tasks
+#
+# Rails applications can define more than one database (primary, cache, cable,
+# queue, ...). Each one gets its own namespaced task, e.g. `db:migrate:cache`.
+# The functions below take an optional database name as the first argument:
+#
+#   rdm                    ->  rails db:migrate
+#   rdm cache              ->  rails db:migrate:cache
+#   rdm VERSION=20231225   ->  rails db:migrate VERSION=20231225
+#   rdm cache STEP=2       ->  rails db:migrate:cache STEP=2
+#   rdm --trace            ->  rails db:migrate --trace
+#
+# The first argument is read as a database name only when it is a bare word.
+# Flags (--trace), variables (STEP=2) and other tasks (db:seed) are passed
+# through to rails untouched, so the previous alias behavior still works.
+function _rails_db_command() {
+  local task="$1"
+  shift
+
+  if [[ $# -gt 0 && "$1" != -* && "$1" != *=* && "$1" != *:* ]]; then
+    task="$task:$1"
+    shift
+    # Echo the resolved task so it is clear which database is being used
+    local -a cmd=(rails "$task" "$@")
+    print -u2 -r -- "Running: ${cmd[*]}"
+  fi
+
+  rails "$task" "$@"
+}
+
+function rdc()  { _rails_db_command db:create "$@" }
+function rdd()  { _rails_db_command db:drop "$@" }
+function rdm()  { _rails_db_command db:migrate "$@" }
+function rdmd() { _rails_db_command db:migrate:down "$@" }
+function rdmr() { _rails_db_command db:migrate:redo "$@" }
+function rdms() { _rails_db_command db:migrate:status "$@" }
+function rdmu() { _rails_db_command db:migrate:up "$@" }
+function rdr()  { _rails_db_command db:rollback "$@" }
+function rdrs() { _rails_db_command db:reset "$@" }
+function rdsl() { _rails_db_command db:schema:load "$@" }
+
 # legacy stuff
 alias sc='ruby script/console'
 alias sd='ruby script/destroy'