How can I get emacs sql-mode to use the mysql config file (.my.cnf)?
I don't think that this is possible but you can set such stuff in the mode configuration itself:
(setq sql-connection-alist
'((pool-a
(sql-product 'mysql)
(sql-server "1.2.3.4")
(sql-user "me")
(sql-password "mypassword")
(sql-database "thedb")
(sql-port 3306))
(pool-b
(sql-product 'mysql)
(sql-server "1.2.3.4")
(sql-user "me")
(sql-password "mypassword")
(sql-database "thedb")
(sql-port 3307))))
(defun sql-connect-preset (name)
"Connect to a predefined SQL connection listed in `sql-connection-alist'"
(eval `(let ,(cdr (assoc name sql-connection-alist))
(flet ((sql-get-login (&rest what)))
(sql-product-interactive sql-product)))))
(defun sql-pool-a ()
(interactive)
(sql-connect-preset 'pool-a))
Have a look at this article for more info.
Sure it's possible. It's quite involved though.
Roughly, the steps are:
- Reading and parsing the ini file using ini.el.
- Merging the different hosts config with the clients config because the latter is applied globally.
- Transforming each host to a suitable format for
sql-connection-alist - Populating
sql-connection-alist - Using
M-x sql-connect(which auto-completes!)
The following code also includes a .pgpass parser, just in case. You'll notice the implementation is simpler.
;;; .pgpass parser
(defun read-file (file)
"Returns file as list of lines."
(with-temp-buffer
(insert-file-contents file)
(split-string (buffer-string) "\n" t)))
(defun pgpass-to-sql-connection (config)
"Returns a suitable list for sql-connection-alist from a pgpass file."
(let ((server (lambda (host port db user _pass)
(list
(concat db ":" user ":" port ":" host)
(list 'sql-product ''postgres)
(list 'sql-server host)
(list 'sql-user user)
(list 'sql-port (string-to-number port))
(list 'sql-database db))))
(pgpass-line (lambda (line)
(apply server (split-string line ":" t)))))
(mapcar pgpass-line config)))
;;; .my.cnf parser
;;; Copied verbatim from https://github.com/daniel-ness/ini.el/blob/master/ini.el
(defun ini-decode (ini_text)
;; text -> alist
(interactive)
(if (not (stringp ini_text))
(error "Must be a string"))
(let ((lines (split-string ini_text "\n"))
(section)
(section-list)
(alist))
(dolist (l lines)
;; skip comments
(unless (or (string-match "^;" l)
(string-match "^[ \t]$" l))
;; catch sections
(if (string-match "^\\[\\(.*\\)\\]$" l)
(progn
(if section
;; add as sub-list
(setq alist (cons `(,section . ,section-list) alist))
(setq alist section-list))
(setq section (match-string 1 l))
(setq section-list nil)))
;; catch properties
(if (string-match "^\\([^\s\t]+\\)[\s\t]*=[\s\t]*\\(.+\\)$" l)
(let ((property (match-string 1 l))
(value (match-string 2 l)))
(progn
(setq section-list (cons `(,property . ,value) section-list)))))))
(if section
;; add as sub-list
(setq alist (cons `(,section . ,section-list) alist))
(setq alist section-list))
alist))
(defun read-ini (file)
"Returns ini file as alist."
(with-temp-buffer
(insert-file-contents file)
(ini-decode (buffer-string))))
(defun filter-alist (wanted-members alist)
"Returns a copy of given alist, with only fields from wanted-members."
(let ((result nil)
(add-if-member (lambda (elt)
(when (member (car elt) wanted-members)
(add-to-list 'result elt t)))))
(mapc add-if-member alist)
result))
(defun merge-alist (original override)
"Returns a union of original and override alist. On key conflict, the latter wins."
(let ((result (copy-alist override))
(add (lambda (elt)
(setq result (add-to-list
'result elt t
(lambda (left right) (equal (car left) (car right))))))))
(mapc add original)
result))
(defun parse-mycnf-hosts (file-path)
"Returns list of hosts with clients' section applied to all hosts."
(let ((hosts nil)
(global nil)
(fields '("user" "host" "database" "password" "port"))
(section-parse (lambda(section)
(if (equal (car section) "client")
(setq global (filter-alist fields (cdr section)))
(let ((host (car section))
(config (filter-alist fields (cdr section))))
(when config (add-to-list 'hosts (cons host config) t))))))
(merge-host-with-global (lambda (host)
(cons (car host) (merge-alist global (cdr host))))))
(mapc section-parse (read-ini file-path))
(mapcar merge-host-with-global hosts)))
(defun mycnf-to-sql-connection (config)
(let ((add-sql-product
(lambda (config)
(let ((head (car config))
(tail (cdr config)))
(cons head (append tail (list (list 'sql-product ''mysql)))))))
(parse-keys-and-values
(lambda (config)
(let ((head (car config))
(tail (cdr config)))
(cons
head
(mapcar
(lambda (element)
(let ((key (car element))
(value (cdr element)))
(cond ((equal key "host") (list 'sql-server value))
((equal key "port") (list 'sql-port (string-to-number value)))
((equal key "user") (list 'sql-user value))
((equal key "password") (list 'sql-password value))
((equal key "database") (list 'sql-database value))
(t (error (format "Unknown key %s" key))))))
tail))))))
(mapcar add-sql-product (mapcar parse-keys-and-values config))))
;;; Actually populating sql-connection-alist
(setq sql-connection-alist
(append
(mycnf-to-sql-connection (parse-mycnf-hosts "~/.my.cnf"))
(pgpass-to-sql-connection (read-file "~/.pgpass"))
))
With the following .my.cnf:
[client]
user=me
[host1]
database=db1
host=db.host1.com
[host2]
database=db2
user=notme
host=db.host2.com
Executing the expression (mycnf-to-sql-connection (parse-mycnf-hosts "~/.my.cnf")) gives me (pretty printed by hand):
(("host2" ((sql-server "db.host2.com")
(sql-user "notme")
(sql-database "db2")))
("host1" ((sql-server "db.host1.com")
(sql-database "db1")
(sql-user "me"))))
Finally, instead of using M-x sql-mysql, use M-x sql-connect and you'll be able to connect using the alias, with auto-completion.