1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
|
#!@GUILE@ \
--debug -e main
!#
;;; pg-tunnel.scm -- Connect to a PostgreSQL instance through an SSH tunnel.
;; Copyright (C) 2015 Artyom V. Poptsov <poptsov.artyom@gmail.com>
;;
;; This program is free software: you can redistribute it and/or
;; modify it under the terms of the GNU General Public License as
;; published by the Free Software Foundation, either version 3 of the
;; License, or (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful, but
;; WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
;; General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program. If not, see <http://www.gnu.org/licenses/>.
;;; Commentary:
;; An example of using Guile-SSH [1] tunnels and Guile-PG [2] to access a
;; remote PostgreSQL database.
;;
;; This program is known to work with the 'master' branch of Guile-SSH, commit
;; '1673d06'.
;;
;; Example:
;; ./pg-tunnel.scm --host=example.org --dbname=example --user=alice \
;; 'select * from people'
;;
;; References:
;;
;; [1] https://github.com/artyom-poptsov/guile-ssh
;; [2] http://www.nongnu.org/guile-pg/
;;; Code:
(use-modules (ice-9 getopt-long)
;; PostgreSQL adapter from Guile-PG
(database postgres)
;; Guile-SSH
(ssh session)
(ssh auth)
(ssh tunnel))
(setlocale LC_ALL "")
(define *mtx* (make-mutex 'allow-external-unlock 'unchecked-unlock))
(lock-mutex *mtx* 0 #f)
(define (start-postgres-tunnel host)
"Start an SSH tunnel to a postgres server running on a HOST."
(let ((session (make-session #:host host #:config #t)))
(connect! session)
(format #t "Session with a server: ~a~%" session)
(authenticate-server session)
(userauth-agent! session)
(let ((tunnel (make-tunnel session
#:host "localhost"
#:port 5432)))
(format #t "Starting the tunnel ~a ...~%" tunnel)
(unlock-mutex *mtx*)
(start-forward tunnel))))
;;; Helper procedures for processing of a result of a query
;; Taken from Guile-PG tutorial
;; <http://www.nongnu.org/guile-pg/doc/Processing-Results.html#Processing-Results>
(define (field-names result)
(map (lambda (field)
(pg-fname result field))
(iota (pg-nfields result))))
(define (get-values result tuple)
(map (lambda (field)
(pg-getvalue result tuple field))
(iota (pg-nfields result))))
(define (tuple->alist result tuple)
(map (lambda (n v) (cons (string->symbol n) v))
(field-names result)
(get-values result tuple)))
;;;
(define (print-help-and-exit)
(display "\
Usage: pg-tunnel [options] query
Options:
--host Name of the host on which DB is running.
--dbname Name of a database.
--user Database user name.
--help Print this message and exit.
Example:
./pg-tunnel.scm --host=example.org --dbname=example --user=alice \\
'select * from people'
")
(exit 0))
(define (main args)
"Entry point."
(let* ((option-spec '((host (value #t) (required? #t))
(dbname (value #t) (required? #t))
(user (value #t) (required? #t))
(help (value #f))))
(options (getopt-long args option-spec))
(dbname (option-ref options 'dbname #f))
(user (option-ref options 'user #f))
(host (option-ref options 'host #f))
(help-needed? (option-ref options 'help #f))
(args (option-ref options '() #f))
;; Start an SSH tunnel.
(thread (call-with-new-thread
(lambda ()
(start-postgres-tunnel host)))))
(and (or help-needed?
(null? args))
(print-help-and-exit))
;; Wait for tunnel to be established.
(lock-mutex *mtx*)
(let ((db (pg-connectdb (format #f "dbname=~a user=~a host=localhost port=5432"
dbname user))))
(format #t "DB connection created: ~a~%" db)
(format #t "Query: ~a~%" args)
(let ((result (pg-exec db (car args))))
(format #t "Response: ~a~%" (tuple->alist result 0))
(cancel-thread thread)))))
;;; pg-tunnel.scm ends here.
|
