Slack/Mattermost integration: URL for Attachments

Summary

When adding an attachment to an issue, the generated link results in a 404 at least in Mattermost (I do not have an account with slack to test)

Steps to reproduce

• Create a new issue
• Add some text
• Attach a file of your choice (either with drag-and-drop or via dialogue, it does not matter)
• Try to open the file in Mattermost

Expected behavior

Can open the attached file in Mattermost.

Actual behavior

The generated link starts with /upload, which is fine when in the gitlab context, but not in the Mattermost context.

Relevant logs and/or screenshots

Compose window in Gitlab:

Output of checks

Results of GitLab application Check

(For installations with omnibus-gitlab package run and paste the output of:

Checking GitLab Shell ...

GitLab Shell version >= 3.6.6 ? ... OK (3.6.6)
Repo base directory exists?
default... yes
Repo storage directories are symlinks?
default... no
Repo paths owned by git:git?
default... yes
Repo paths access is drwxrws---?
default... yes
hooks directories in repos are links: ...
15/3 ... repository is empty
36/5 ... repository is empty
41/12 ... ok
13/13 ... ok
13/14 ... ok
41/15 ... ok
41/16 ... ok
41/17 ... ok
30/18 ... repository is empty
301/21 ... ok
44/24 ... ok
13/25 ... repository is empty
49/27 ... ok
49/28 ... ok
50/29 ... ok
56/32 ... repository is empty
49/34 ... ok
50/35 ... ok
50/36 ... ok
49/37 ... ok
9/38 ... ok
50/42 ... ok
9/43 ... ok
9/44 ... ok
63/46 ... ok
64/47 ... ok
66/50 ... ok
66/51 ... ok
65/52 ... ok
65/53 ... ok
65/55 ... ok
65/57 ... ok
66/58 ... ok
66/60 ... ok
66/61 ... ok
50/62 ... ok
68/63 ... ok
75/64 ... ok
75/65 ... ok
75/66 ... ok
65/67 ... ok
65/68 ... ok
65/69 ... ok
65/70 ... ok
65/71 ... ok
66/72 ... ok
78/73 ... ok
78/74 ... ok
78/75 ... ok
56/76 ... ok
52/82 ... ok
57/87 ... ok
50/88 ... ok
52/90 ... ok
65/91 ... ok
51/94 ... ok
94/96 ... ok
37/97 ... ok
97/99 ... ok
97/100 ... ok
97/101 ... ok
97/103 ... ok
97/105 ... ok
101/106 ... ok
50/107 ... ok
50/108 ... ok
68/109 ... ok
41/110 ... ok
97/111 ... ok
50/112 ... ok
50/113 ... ok
44/114 ... ok
302/116 ... ok
302/117 ... ok
50/118 ... ok
43/119 ... ok
128/126 ... ok
128/127 ... repository is empty
137/130 ... ok
41/132 ... ok
97/135 ... ok
139/136 ... repository is empty
43/138 ... ok
56/140 ... repository is empty
44/141 ... ok
43/142 ... ok
142/144 ... ok
87/148 ... ok
14/149 ... repository is empty
43/152 ... ok
97/153 ... ok
61/156 ... ok
21/157 ... ok
142/158 ... ok
43/160 ... ok
43/161 ... ok
148/162 ... ok
87/163 ... ok
43/164 ... ok
147/165 ... ok
147/166 ... ok
43/167 ... ok
50/168 ... ok
156/169 ... ok
156/170 ... ok
50/171 ... ok
137/173 ... ok
43/174 ... ok
147/175 ... ok
166/177 ... ok
43/178 ... ok
43/179 ... ok
43/180 ... ok
43/181 ... ok
43/182 ... ok
43/183 ... ok
43/184 ... ok
43/185 ... ok
43/186 ... ok
166/187 ... ok
166/188 ... ok
50/189 ... ok
34/191 ... ok
95/192 ... ok
182/193 ... ok
156/194 ... ok
188/195 ... ok
43/196 ... ok
126/197 ... ok
202/198 ... ok
130/199 ... repository is empty
55/201 ... ok
65/202 ... ok
191/206 ... ok
192/207 ... repository is empty
192/208 ... ok
192/209 ... ok
192/210 ... ok
28/211 ... ok
156/212 ... ok
48/213 ... ok
50/214 ... ok
43/216 ... ok
43/218 ... ok
43/219 ... ok
56/220 ... ok
15/221 ... repository is empty
34/222 ... ok
156/223 ... ok
34/224 ... ok
191/225 ... ok
44/226 ... ok
156/227 ... ok
302/228 ... ok
37/229 ... ok
34/230 ... ok
178/233 ... ok
178/234 ... ok
208/235 ... ok
209/236 ... ok
124/238 ... ok
145/239 ... ok
57/240 ... ok
43/241 ... ok
20/243 ... ok
156/244 ... ok
156/245 ... ok
156/246 ... ok
156/247 ... ok
57/248 ... repository is empty
188/249 ... ok
156/250 ... ok
156/251 ... ok
156/252 ... ok
156/253 ... ok
218/254 ... ok
156/255 ... ok
149/256 ... ok
156/257 ... ok
21/259 ... ok
100/260 ... ok
207/264 ... ok
207/265 ... ok
207/266 ... ok
224/267 ... ok
156/268 ... ok
156/269 ... ok
44/270 ... ok
44/271 ... ok
124/272 ... ok
145/275 ... ok
140/276 ... ok
9/277 ... ok
224/278 ... ok
57/279 ... ok
57/280 ... ok
191/283 ... ok
221/284 ... ok
221/285 ... ok
221/286 ... ok
238/287 ... ok
238/288 ... ok
224/289 ... ok
57/290 ... ok
156/291 ... ok
54/292 ... repository is empty
156/293 ... ok
156/294 ... ok
43/295 ... ok
43/296 ... ok
156/297 ... ok
57/299 ... ok
57/300 ... ok
55/301 ... repository is empty
65/302 ... ok
238/304 ... ok
241/305 ... ok
156/307 ... ok
247/308 ... repository is empty
145/309 ... ok
16/310 ... ok
124/311 ... ok
145/312 ... ok
250/313 ... ok
302/314 ... ok
41/317 ... ok
207/318 ... ok
119/319 ... ok
151/320 ... ok
206/321 ... ok
250/324 ... ok
37/326 ... ok
119/327 ... ok
119/328 ... ok
119/329 ... ok
238/330 ... ok
87/332 ... ok
57/333 ... ok
238/334 ... ok
9/335 ... ok
141/337 ... ok
132/338 ... ok
132/339 ... ok
253/342 ... ok
253/343 ... ok
209/344 ... ok
191/347 ... ok
43/348 ... ok
57/349 ... ok
178/350 ... ok
119/351 ... ok
261/352 ... ok
156/353 ... ok
156/354 ... ok
221/356 ... ok
238/357 ... ok
221/358 ... ok
17/359 ... ok
224/360 ... ok
277/361 ... ok
277/362 ... ok
277/363 ... ok
21/364 ... ok
277/365 ... ok
278/366 ... ok
156/367 ... ok
209/368 ... ok
156/369 ... ok
66/370 ... ok
281/371 ... ok
65/372 ... ok
55/373 ... repository is empty
282/374 ... ok
49/376 ... ok
191/377 ... ok
156/378 ... ok
78/379 ... ok
147/380 ... ok
218/381 ... ok
78/382 ... ok
43/386 ... ok
8/387 ... ok
8/388 ... ok
44/389 ... ok
241/390 ... ok
241/391 ... ok
147/392 ... ok
287/393 ... ok
8/394 ... ok
147/395 ... ok
124/396 ... ok
16/397 ... ok
124/398 ... repository is empty
302/400 ... ok
302/401 ... ok
151/402 ... ok
143/403 ... repository is empty
122/404 ... repository is empty
85/405 ... ok
209/406 ... ok
21/407 ... ok
209/408 ... ok
199/411 ... ok
241/414 ... ok
65/415 ... ok
65/416 ... ok
65/417 ... ok
50/418 ... ok
50/419 ... ok
50/420 ... ok
147/421 ... ok
287/424 ... ok
191/425 ... ok
287/426 ... ok
26/428 ... ok
156/429 ... ok
132/430 ... ok
298/432 ... ok
298/433 ... ok
298/434 ... ok
298/435 ... ok
298/436 ... ok
298/438 ... ok
298/439 ... ok
299/440 ... ok
17/441 ... ok
56/442 ... ok
50/443 ... ok
191/444 ... ok
218/446 ... ok
278/447 ... ok
238/448 ... ok
238/449 ... ok
253/450 ... ok
17/452 ... repository is empty
315/453 ... ok
156/454 ... ok
209/455 ... ok
209/456 ... ok
37/458 ... ok
41/459 ... ok
209/460 ... ok
209/461 ... ok
26/462 ... ok
322/463 ... ok
323/465 ... ok
323/466 ... ok
323/467 ... ok
37/468 ... ok
238/469 ... ok
324/475 ... ok
34/477 ... ok
44/481 ... ok
324/483 ... ok
324/484 ... ok
327/486 ... ok
327/487 ... ok
327/488 ... ok
324/489 ... ok
315/490 ... ok
145/491 ... ok
250/492 ... ok
147/493 ... ok
87/494 ... ok
41/495 ... ok
41/500 ... ok
337/503 ... ok
337/504 ... ok
75/506 ... ok
337/507 ... ok
337/508 ... ok
50/509 ... ok
324/510 ... ok
209/511 ... ok
238/512 ... ok
287/513 ... ok
191/560 ... ok
361/569 ... ok
361/570 ... ok
361/571 ... ok
361/572 ... ok
361/573 ... ok
361/574 ... ok
361/575 ... ok
361/576 ... ok
147/577 ... ok
337/578 ... ok
337/579 ... ok
337/580 ... ok
337/581 ... ok
337/582 ... ok
238/583 ... ok
97/584 ... ok
41/585 ... ok
41/586 ... ok
41/587 ... ok
41/589 ... ok
224/590 ... ok
166/591 ... ok
224/592 ... ok
50/594 ... ok
50/595 ... ok
50/596 ... repository is empty
50/597 ... repository is empty
50/598 ... ok
209/601 ... ok
8/603 ... ok
85/604 ... repository is empty
85/605 ... ok
85/606 ... ok
85/607 ... ok
85/608 ... ok
85/609 ... repository is empty
85/610 ... ok
85/611 ... ok
85/612 ... ok
85/613 ... repository is empty
367/614 ... ok
367/615 ... ok
8/617 ... ok
298/619 ... repository is empty
371/620 ... ok
371/621 ... ok
371/622 ... ok
371/623 ... ok
371/624 ... ok
371/625 ... ok
371/626 ... ok
371/627 ... ok
9/636 ... ok
9/637 ... ok
9/638 ... ok
9/639 ... ok
9/640 ... ok
9/641 ... ok
9/642 ... ok
9/643 ... ok
372/644 ... ok
9/645 ... ok
287/646 ... repository is empty
375/648 ... repository is empty
100/649 ... ok
372/650 ... ok
224/652 ... ok
224/653 ... ok
372/654 ... ok
191/656 ... ok
238/657 ... ok
390/666 ... ok
9/667 ... ok
400/668 ... ok
400/669 ... ok
400/670 ... ok
400/671 ... ok
400/672 ... ok
400/673 ... ok
400/674 ... ok
400/675 ... ok
140/677 ... ok
135/680 ... ok
149/681 ... ok
9/682 ... ok
259/683 ... repository is empty
259/684 ... repository is empty
259/685 ... repository is empty
145/686 ... ok
375/689 ... ok
372/690 ... ok
372/691 ... ok
372/692 ... ok
418/693 ... ok
20/694 ... ok
418/695 ... ok
418/696 ... ok
372/697 ... ok
372/698 ... ok
56/699 ... ok
Running /opt/gitlab/embedded/service/gitlab-shell/bin/check
Check GitLab API access: OK
Access to /var/opt/gitlab/.ssh/authorized_keys: OK
Send ping to redis server: OK
gitlab-shell self-check successful

Checking GitLab Shell ... Finished

Checking Sidekiq ...

Running? ... yes
Number of Sidekiq processes ... 1

Checking Sidekiq ... Finished

Checking Reply by email ...

Reply by email is disabled in config/gitlab.yml

Checking Reply by email ... Finished

Checking LDAP ...

LDAP users with access to your GitLab server (only showing the first 100 results)

Checking LDAP ... Finished

[Left out the LDAP users)

Checking GitLab ...

Git configured with autocrlf=input? ... yes
Database config exists? ... yes
All migrations up? ... yes
Database contains orphaned GroupMembers? ... no
GitLab config exists? ... yes
GitLab config outdated? ... no
Log directory writable? ... yes
Tmp directory writable? ... yes
Uploads directory setup correctly? ... yes
Init script exists? ... skipped (omnibus-gitlab has no init script)
Init script up-to-date? ... skipped (omnibus-gitlab has no init script)
projects have namespace: ...
15/3 ... yes
36/5 ... yes
41/12 ... yes
13/13 ... yes
13/14 ... yes
41/15 ... yes
41/16 ... yes
41/17 ... yes
30/18 ... yes
301/21 ... yes
44/24 ... yes
13/25 ... yes
49/27 ... yes
49/28 ... yes
50/29 ... yes
56/32 ... yes
49/34 ... yes
50/35 ... yes
50/36 ... yes
49/37 ... yes
9/38 ... yes
50/42 ... yes
9/43 ... yes
9/44 ... yes
63/46 ... yes
64/47 ... yes
66/50 ... yes
66/51 ... yes
65/52 ... yes
65/53 ... yes
65/55 ... yes
65/57 ... yes
66/58 ... yes
66/60 ... yes
66/61 ... yes
50/62 ... yes
68/63 ... yes
75/64 ... yes
75/65 ... yes
75/66 ... yes
65/67 ... yes
65/68 ... yes
65/69 ... yes
65/70 ... yes
65/71 ... yes
66/72 ... yes
78/73 ... yes
78/74 ... yes
78/75 ... yes
56/76 ... yes
52/82 ... yes
57/87 ... yes
50/88 ... yes
52/90 ... yes
65/91 ... yes
51/94 ... yes
94/96 ... yes
37/97 ... yes
97/99 ... yes
97/100 ... yes
97/101 ... yes
97/103 ... yes
97/105 ... yes
101/106 ... yes
50/107 ... yes
50/108 ... yes
68/109 ... yes
41/110 ... yes
97/111 ... yes
50/112 ... yes
50/113 ... yes
44/114 ... yes
302/116 ... yes
302/117 ... yes
50/118 ... yes
43/119 ... yes
128/126 ... yes
128/127 ... yes
137/130 ... yes
41/132 ... yes
97/135 ... yes
139/136 ... yes
43/138 ... yes
56/140 ... yes
44/141 ... yes
43/142 ... yes
142/144 ... yes
87/148 ... yes
14/149 ... yes
43/152 ... yes
97/153 ... yes
61/156 ... yes
21/157 ... yes
142/158 ... yes
43/160 ... yes
43/161 ... yes
148/162 ... yes
87/163 ... yes
43/164 ... yes
147/165 ... yes
147/166 ... yes
43/167 ... yes
50/168 ... yes
156/169 ... yes
156/170 ... yes
50/171 ... yes
137/173 ... yes
43/174 ... yes
147/175 ... yes
166/177 ... yes
43/178 ... yes
43/179 ... yes
43/180 ... yes
43/181 ... yes
43/182 ... yes
43/183 ... yes
43/184 ... yes
43/185 ... yes
43/186 ... yes
166/187 ... yes
166/188 ... yes
50/189 ... yes
34/191 ... yes
95/192 ... yes
182/193 ... yes
156/194 ... yes
188/195 ... yes
43/196 ... yes
126/197 ... yes
202/198 ... yes
130/199 ... yes
55/201 ... yes
65/202 ... yes
191/206 ... yes
192/207 ... yes
192/208 ... yes
192/209 ... yes
192/210 ... yes
28/211 ... yes
156/212 ... yes
48/213 ... yes
50/214 ... yes
43/216 ... yes
43/218 ... yes
43/219 ... yes
56/220 ... yes
15/221 ... yes
34/222 ... yes
156/223 ... yes
34/224 ... yes
191/225 ... yes
44/226 ... yes
156/227 ... yes
302/228 ... yes
37/229 ... yes
34/230 ... yes
178/233 ... yes
178/234 ... yes
208/235 ... yes
209/236 ... yes
124/238 ... yes
145/239 ... yes
57/240 ... yes
43/241 ... yes
20/243 ... yes
156/244 ... yes
156/245 ... yes
156/246 ... yes
156/247 ... yes
57/248 ... yes
188/249 ... yes
156/250 ... yes
156/251 ... yes
156/252 ... yes
156/253 ... yes
218/254 ... yes
156/255 ... yes
149/256 ... yes
156/257 ... yes
21/259 ... yes
100/260 ... yes
207/264 ... yes
207/265 ... yes
207/266 ... yes
224/267 ... yes
156/268 ... yes
156/269 ... yes
44/270 ... yes
44/271 ... yes
124/272 ... yes
145/275 ... yes
140/276 ... yes
9/277 ... yes
224/278 ... yes
57/279 ... yes
57/280 ... yes
191/283 ... yes
221/284 ... yes
221/285 ... yes
221/286 ... yes
238/287 ... yes
238/288 ... yes
224/289 ... yes
57/290 ... yes
156/291 ... yes
54/292 ... yes
156/293 ... yes
156/294 ... yes
43/295 ... yes
43/296 ... yes
156/297 ... yes
57/299 ... yes
57/300 ... yes
55/301 ... yes
65/302 ... yes
238/304 ... yes
241/305 ... yes
156/307 ... yes
247/308 ... yes
145/309 ... yes
16/310 ... yes
124/311 ... yes
145/312 ... yes
250/313 ... yes
302/314 ... yes
41/317 ... yes
207/318 ... yes
119/319 ... yes
151/320 ... yes
206/321 ... yes
250/324 ... yes
37/326 ... yes
119/327 ... yes
119/328 ... yes
119/329 ... yes
238/330 ... yes
87/332 ... yes
57/333 ... yes
238/334 ... yes
9/335 ... yes
141/337 ... yes
132/338 ... yes
132/339 ... yes
253/342 ... yes
253/343 ... yes
209/344 ... yes
191/347 ... yes
43/348 ... yes
57/349 ... yes
178/350 ... yes
119/351 ... yes
261/352 ... yes
156/353 ... yes
156/354 ... yes
221/356 ... yes
238/357 ... yes
221/358 ... yes
17/359 ... yes
224/360 ... yes
277/361 ... yes
277/362 ... yes
277/363 ... yes
21/364 ... yes
277/365 ... yes
278/366 ... yes
156/367 ... yes
209/368 ... yes
156/369 ... yes
66/370 ... yes
281/371 ... yes
65/372 ... yes
55/373 ... yes
282/374 ... yes
49/376 ... yes
191/377 ... yes
156/378 ... yes
78/379 ... yes
147/380 ... yes
218/381 ... yes
78/382 ... yes
43/386 ... yes
8/387 ... yes
8/388 ... yes
44/389 ... yes
241/390 ... yes
241/391 ... yes
147/392 ... yes
287/393 ... yes
8/394 ... yes
147/395 ... yes
124/396 ... yes
16/397 ... yes
124/398 ... yes
302/400 ... yes
302/401 ... yes
151/402 ... yes
143/403 ... yes
122/404 ... yes
85/405 ... yes
209/406 ... yes
21/407 ... yes
209/408 ... yes
199/411 ... yes
241/414 ... yes
65/415 ... yes
65/416 ... yes
65/417 ... yes
50/418 ... yes
50/419 ... yes
50/420 ... yes
147/421 ... yes
287/424 ... yes
191/425 ... yes
287/426 ... yes
26/428 ... yes
156/429 ... yes
132/430 ... yes
298/432 ... yes
298/433 ... yes
298/434 ... yes
298/435 ... yes
298/436 ... yes
298/438 ... yes
298/439 ... yes
299/440 ... yes
17/441 ... yes
56/442 ... yes
50/443 ... yes
191/444 ... yes
218/446 ... yes
278/447 ... yes
238/448 ... yes
238/449 ... yes
253/450 ... yes
17/452 ... yes
315/453 ... yes
156/454 ... yes
209/455 ... yes
209/456 ... yes
37/458 ... yes
41/459 ... yes
209/460 ... yes
209/461 ... yes
26/462 ... yes
322/463 ... yes
323/465 ... yes
323/466 ... yes
323/467 ... yes
37/468 ... yes
238/469 ... yes
324/475 ... yes
34/477 ... yes
44/481 ... yes
324/483 ... yes
324/484 ... yes
327/486 ... yes
327/487 ... yes
327/488 ... yes
324/489 ... yes
315/490 ... yes
145/491 ... yes
250/492 ... yes
147/493 ... yes
87/494 ... yes
41/495 ... yes
41/500 ... yes
337/503 ... yes
337/504 ... yes
75/506 ... yes
337/507 ... yes
337/508 ... yes
50/509 ... yes
324/510 ... yes
209/511 ... yes
238/512 ... yes
287/513 ... yes
191/560 ... yes
361/569 ... yes
361/570 ... yes
361/571 ... yes
361/572 ... yes
361/573 ... yes
361/574 ... yes
361/575 ... yes
361/576 ... yes
147/577 ... yes
337/578 ... yes
337/579 ... yes
337/580 ... yes
337/581 ... yes
337/582 ... yes
238/583 ... yes
97/584 ... yes
41/585 ... yes
41/586 ... yes
41/587 ... yes
41/589 ... yes
224/590 ... yes
166/591 ... yes
224/592 ... yes
50/594 ... yes
50/595 ... yes
50/596 ... yes
50/597 ... yes
50/598 ... yes
209/601 ... yes
8/603 ... yes
85/604 ... yes
85/605 ... yes
85/606 ... yes
85/607 ... yes
85/608 ... yes
85/609 ... yes
85/610 ... yes
85/611 ... yes
85/612 ... yes
85/613 ... yes
367/614 ... yes
367/615 ... yes
8/617 ... yes
298/619 ... yes
371/620 ... yes
371/621 ... yes
371/622 ... yes
371/623 ... yes
371/624 ... yes
371/625 ... yes
371/626 ... yes
371/627 ... yes
9/636 ... yes
9/637 ... yes
9/638 ... yes
9/639 ... yes
9/640 ... yes
9/641 ... yes
9/642 ... yes
9/643 ... yes
372/644 ... yes
9/645 ... yes
287/646 ... yes
375/648 ... yes
100/649 ... yes
372/650 ... yes
224/652 ... yes
224/653 ... yes
372/654 ... yes
191/656 ... yes
238/657 ... yes
390/666 ... yes
9/667 ... yes
400/668 ... yes
400/669 ... yes
400/670 ... yes
400/671 ... yes
400/672 ... yes
400/673 ... yes
400/674 ... yes
400/675 ... yes
140/677 ... yes
135/680 ... yes
149/681 ... yes
9/682 ... yes
259/683 ... yes
259/684 ... yes
259/685 ... yes
145/686 ... yes
375/689 ... yes
372/690 ... yes
372/691 ... yes
372/692 ... yes
418/693 ... yes
20/694 ... yes
418/695 ... yes
418/696 ... yes
372/697 ... yes
372/698 ... yes
56/699 ... yes
Redis version >= 2.8.0? ... yes
Ruby version >= 2.1.0 ? ... yes (2.3.1)
Your git bin path is "/opt/gitlab/embedded/bin/git"
Git version >= 2.7.3 ? ... yes (2.7.4)
Active users: 332

Checking GitLab ... Finished

Results of GitLab environment info

System information
System:         Debian 8.6
Current User:   git
Using RVM:      no
Ruby Version:   2.3.1p112
Gem Version:    2.6.6
Bundler Version:1.13.5
Rake Version:   10.5.0
Sidekiq Version:4.2.1

GitLab information
Version:        8.13.0
Revision:       053a0a2
Directory:      /opt/gitlab/embedded/service/gitlab-rails
DB Adapter:     postgresql
URL:            https://gitlab.[redacted].de
HTTP Clone URL: https://gitlab.[redacted].de/some-group/some-project.git
SSH Clone URL:  git@gitlab.[redacted].de:some-group/some-project.git
Using LDAP:     yes
Using Omniauth: no

GitLab Shell
Version:        3.6.6
Repository storage paths:
- default:      /var/opt/gitlab/git-data/repositories
Hooks:          /opt/gitlab/embedded/service/gitlab-shell/hooks/
Git:            /opt/gitlab/embedded/bin/git

Possible fixes

None that I know of.