From a1a29f7c0b5746aa5676e546b8ebae7518d9070b Mon Sep 17 00:00:00 2001 From: Aspen Smith Date: Sun, 24 Mar 2024 10:32:15 -0400 Subject: feat(web/panettone): Add a system for database migrations Add a system for writing, running, and tracking database migrations (changes to the database schema) over time, inspired by but significantly simpler than postmodern-passenger-pigeon. Migrations can be generated by running (PANETTONE.MODEL:GENERATE-MIGRATION "name"), and are numerically ordered lisp files that define (at least) a function called UP, which runs the migration. The migrations that have been run against the database are tracked in the `migrations` table, and when the `(PANETTONE.MODEL:MIGRATE)` function is called (as it is on startup), all migrations that have not yet been run are run within a transaction. This includes one migration `1-init-schema.lisp`, which migrates the database (idempotently) to the current state of the schema. Change-Id: Id243a47763abea649784b12f25a6d05c2267381c Reviewed-on: https://cl.tvl.fyi/c/depot/+/11253 Tested-by: BuildkiteCI Reviewed-by: sterni --- web/panettone/default.nix | 11 +- web/panettone/src/migrations/1-init-schema.lisp | 23 +++ web/panettone/src/model.lisp | 223 ++++++++++++++++++++---- web/panettone/src/packages.lisp | 6 +- web/panettone/src/panettone.lisp | 2 +- 5 files changed, 228 insertions(+), 37 deletions(-) create mode 100644 web/panettone/src/migrations/1-init-schema.lisp diff --git a/web/panettone/default.nix b/web/panettone/default.nix index 283f83499487..91ac34ea5482 100644 --- a/web/panettone/default.nix +++ b/web/panettone/default.nix @@ -1,4 +1,4 @@ -{ depot, ... }: +{ depot, pkgs, ... }: depot.nix.buildLisp.program { name = "panettone"; @@ -9,6 +9,7 @@ depot.nix.buildLisp.program { cl-ppcre cl-smtp cl-who + str defclass-std drakma easy-routes @@ -23,6 +24,14 @@ depot.nix.buildLisp.program { srcs = [ ./panettone.asd ./src/packages.lisp + (pkgs.writeText "build.lisp" '' + (defpackage build + (:use :cl :alexandria) + (:export :*migrations-dir*)) + (in-package :build) + (declaim (optimize (safety 3))) + (defvar *migrations-dir* "${./src/migrations}") + '') ./src/util.lisp ./src/css.lisp ./src/email.lisp diff --git a/web/panettone/src/migrations/1-init-schema.lisp b/web/panettone/src/migrations/1-init-schema.lisp new file mode 100644 index 000000000000..3be6c4fcc0d0 --- /dev/null +++ b/web/panettone/src/migrations/1-init-schema.lisp @@ -0,0 +1,23 @@ +"Initialize the database schema from before migrations were added" + +(defun ddl/create-issue-status () + "Issue DDL to create the `issue-status' type, if it doesn't exist" + (unless (query (:select (:exists (:select 1 + :from 'pg_type + :where (:= 'typname "issue_status")))) + :single) + (query (sql-compile + `(:create-enum issue-status ,panettone.model:+issue-statuses+))))) + +(defun ddl/create-tables () + "Issue DDL to create all tables, if they don't already exist." + (dolist (table '(panettone.model:issue + panettone.model:issue-comment + panettone.model:issue-event + panettone.model:user-settings)) + (unless (table-exists-p (dao-table-name table)) + (create-table table)))) + +(defun up () + (ddl/create-issue-status) + (ddl/create-tables)) diff --git a/web/panettone/src/model.lisp b/web/panettone/src/model.lisp index c54a0ae474bf..aa52b4a49320 100644 --- a/web/panettone/src/model.lisp +++ b/web/panettone/src/model.lisp @@ -20,6 +20,19 @@ initialised at launch time.") "Initialises the connection spec used for all Postgres connections." (setq *pg-spec* (make-pg-spec))) +(defun connect-to-db () + "Connect using *PG-SPEC* at the top-level, for use during development" + (apply #'connect-toplevel + (loop for v in *pg-spec* + until (eq v :pooled-p) + collect v))) + +(defun pg-spec->url (&optional (spec *pg-spec*)) + (destructuring-bind (db user password host &key port &allow-other-keys) spec + (format nil + "postgres://~A:~A@~A:~A/~A" + user password host port db))) + ;;; ;;; Schema ;;; @@ -77,15 +90,6 @@ initialised at launch time.") "Type specifier for the status of an `issue'" (cons 'member +issue-statuses+)) -(defun ddl/create-issue-status () - "Issue DDL to create the `issue-status' type, if it doesn't exist" - (unless (query (:select (:exists (:select 1 - :from 'pg_type - :where (:= 'typname "issue_status")))) - :single) - (query (sql-compile - `(:create-enum issue-status ,+issue-statuses+))))) - (defclass has-created-at () ((created-at :col-type timestamp :col-default (local-time:now) @@ -192,23 +196,168 @@ its new value will be formatted using ~A into NEW-VALUE")) (!dao-def) (!foreign 'issues 'issue-id 'id :on-delete :cascade :on-update :cascade)) -(define-constant +all-tables+ - '(issue - issue-comment - issue-event - user-settings) - :test #'equal) +(defclass migration () + ((version + :col-type bigint + :primary-key t + :initarg :version + :accessor version) + (name :col-type string :initarg :name :accessor name) + (docstring :col-type string :initarg :docstring :accessor docstring) + (path :col-type string + :type pathname + :initarg :path + :accessor path + :col-export namestring + :col-import parse-namestring) + (package :type keyword :initarg :package :accessor migration-package)) + (:metaclass dao-class) + (:keys version) + (:table-name migrations) + (:documentation "Migration scripts that have been run on the database")) +(deftable migration (!dao-def)) -(defun ddl/create-tables () - "Issue DDL to create all tables, if they don't already exist." - (dolist (table +all-tables+) - (unless (table-exists-p (dao-table-name table)) - (create-table table)))) +;;; +;;; Migrations +;;; -(defun ddl/init () - "Idempotently initialize the full database schema for Panettone" - (ddl/create-issue-status) - (ddl/create-tables)) +(defun ensure-migrations-table () + "Ensure the migrations table exists" + (unless (table-exists-p (dao-table-name 'migration)) + (create-table 'migration))) + +(defvar *migrations-dir* + ;; Let the nix build override the migrations dir for us + (or (when-let ((package (find-package :build))) + (let ((sym (find-symbol "*MIGRATIONS-DIR*" package))) + (when (boundp sym) + (symbol-value sym)))) + "migrations/") + "The directory where migrations are stored") + +(defun load-migration-docstring (migration-path) + "If the first form in the file pointed to by `migration-pathname` is + a string, return it, otherwise return NIL." + + (handler-case + (with-open-file (s migration-path) + (when-let ((form (read s))) + (when (stringp form) form))) + (t () nil))) + +(defun load-migration (path) + (let* ((parts (str:split #\- (pathname-name path) :limit 2)) + (version (parse-integer (car parts))) + (name (cadr parts)) + (docstring (load-migration-docstring path)) + (package (intern (format nil "MIGRATION-~A" version) + :keyword)) + (migration (make-instance 'migration + :version version + :name name + :docstring docstring + :path path + :package package))) + (uiop/package:ensure-package package + :use '(#:common-lisp + #:postmodern + #:panettone.model)) + (let ((*package* (find-package package))) + (load path)) + + migration)) + +(defun run-migration (migration) + (declare (type migration migration)) + (with-transaction () + (format t "Running migration ~A (version ~A)" + (name migration) + (version migration)) + (query + (sql-compile + `(:delete-from migrations + :where (= version ,(version migration))))) + (uiop:symbol-call (migration-package migration) :up) + (insert-dao migration))) + +(defun list-migration-files () + (let ((dir (if (char-equal (uiop:last-char *migrations-dir*) #\/) + *migrations-dir* + (concatenate 'string *migrations-dir* "/")))) + (remove-if-not + (lambda (pn) (string= "lisp" (pathname-type pn))) + (uiop:directory-files dir)))) + +(defun load-migrations () + (mapcar #'load-migration (list-migration-files))) + +(defun generate-migration (name &key documentation) + "Generate a new database migration with the given NAME, optionally +prepopulated with the given DOCUMENTATION. + +Returns the file that the migration is located at, as a `pathname'. Write Lisp +code in this migration file to define a function called `up', which will be run +in the context of a database transaction and should perform the migration." + (let* ((version (get-universal-time)) + (filename (format nil "~A-~A.lisp" + version + name)) + (pathname + (merge-pathnames filename *migrations-dir*))) + (with-open-file (stream pathname + :direction :output + :if-does-not-exist :create) + (when documentation + (format stream "~S~%~%" documentation)) + + (format stream "(defun up ()~%)")) + pathname)) + +(defun migrations-already-run () + "Query the database for a list of migrations that have already been run" + (query-dao 'migration (sql-compile '(:select * :from migrations)))) + +(define-condition migration-name-mismatch () + ((version :type integer :initarg :version) + (name-in-database :type string :initarg :name-in-database) + (name-in-code :type string :initarg :name-in-code)) + (:report + (lambda (cond stream) + (format stream "Migration mismatch: Migration version ~A has name ~S in the database, but we have name ~S" + (slot-value cond 'version) + (slot-value cond 'name-in-database) + (slot-value cond 'name-in-code))))) + +(defun migrate () + "Migrate the database, running all migrations that have not yet been run" + (ensure-migrations-table) + (let* ((all-migrations (load-migrations)) + (already-run (migrations-already-run)) + (num-migrations-run 0)) + (iter (for migration in all-migrations) + (if-let ((existing (find-if (lambda (existing) + (= (version existing) + (version migration))) + already-run))) + (progn + (unless (string= (name migration) + (name existing)) + (restart-case + (error 'migration-name-mismatch + :version (version existing) + :name-in-database (name existing) + :name-in-code (name migration)) + (skip () + :report "Skip this migration" + (next-iteration)) + (run-and-overwrite () + :report "Run this migration anyway, overwriting the previous migration" + (run-migration migration)))) + (next-iteration)) + ;; otherwise, run the migration + (run-migration migration)) + (incf num-migrations-run)) + (format nil "Ran ~A migration~:P" num-migrations-run))) ;;; ;;; Querying @@ -253,11 +402,11 @@ type `ISSUE-NOT-FOUND'." (select (if (find :num-comments with) `(:select issues.* (:as (:count issue-comments.id) num-comments) - :from issues - :left-join issue-comments - :on (:= issues.id issue-comments.issue-id) - ,@condition - :group-by issues.id) + :from issues + :left-join issue-comments + :on (:= issues.id issue-comments.issue-id) + ,@condition + :group-by issues.id) `(:select * :from issues ,@condition))) (query (sql-compile `(:order-by ,select (:desc id))))) @@ -409,12 +558,22 @@ explicitly subscribing to / unsubscribing from individual issues." (comment - (ddl/init) + (make-instance 'issue :subject "test") - (create-issue :subject "test" - :author-dn "cn=grfn,ou=users,dc=tvl,dc=fyi") + + (with-connection *pg-spec* + (create-issue :subject "test" + :author-dn "cn=aspen,ou=users,dc=tvl,dc=fyi")) (issue-commenter-dns 1) (issue-subscribers 1) + ;; Creating new migrations + (setq *migrations-dir* (merge-pathnames "migrations/")) + (generate-migration "init-schema" + :documentation "Initialize the database schema") + + ;; Running migrations + (with-connection *pg-spec* + (migrate)) ) diff --git a/web/panettone/src/packages.lisp b/web/panettone/src/packages.lisp index 4ff4c070f087..c8c1842f440e 100644 --- a/web/panettone/src/packages.lisp +++ b/web/panettone/src/packages.lisp @@ -36,16 +36,16 @@ (:import-from :alexandria :if-let :when-let :define-constant) (:export :prepare-db-connections - :ddl/init + :migrate :*pg-spec* :user-settings :user-dn :enable-email-notifications-p :settings-for-user :update-user-settings :enable-email-notifications - :issue :issue-comment :issue-event + :issue :issue-comment :issue-event :migration :id :subject :body :author-dn :issue-id :status :created-at :acting-user-dn - :field :previous-value :new-value + :field :previous-value :new-value :+issue-statuses+ :get-issue :issue-exists-p :list-issues :create-issue :set-issue-status :update-issue :delete-issue :issue-not-found :not-found-id diff --git a/web/panettone/src/panettone.lisp b/web/panettone/src/panettone.lisp index d87ac5ed4653..bdcf0d05b39b 100644 --- a/web/panettone/src/panettone.lisp +++ b/web/panettone/src/panettone.lisp @@ -606,7 +606,7 @@ given subject an body (in a thread, to avoid blocking)" (defun migrate-db () "Migrate the database to the latest version of the schema" (pomo:with-connection *pg-spec* - (model:ddl/init))) + (model:migrate))) (defun start-panettone (&key port session-secret) (authn:initialise-oauth2) -- cgit 1.4.1