Re: [fossil-users] Fossil behind reverse proxy
Hi Kyle, Thanks for your extensive reply. I was going through the code and had stumbled upon the SCRIPT_NAME trick when your mail came in and confirmed that it was indeed possible. In the default admin setup, the logo path needed to be fixed from '/logo' to '$baseurl/logo', but then it works fully. I can confirm that it also works on Linux and Windows, not just Darwin. For folks not using Apache it would be good if your below 'how to' could mention that the reverse proxy needs to strip the baseurl of the uri it forwards to the Fossil server (i.e.: '/fossil/index' must be forwarded as '/index'). However, this is a hack that works by accident. It works because 'server' and 'cgi' share code paths and the 'server' code flow reads part of the CGI environment even though it shouldn't. Can you imagine the configuration headache if one had an unrelated SCRIPT_NAME environment variable and wasn't aware of this feature... Also, the hack fixes the baseUrl to one defined prefix. Access to a fossil server setup using this hack becomes unusable from the web if accessed directly as well, nor can multiple baseurl's be mapped to a single fossil server instance. Whilst I'm quite happy that the hack fixes my immediate problem, I think a better engineered solution is preferrable. First of all, I note that baseUrl relocation in server mode works without problem as you have established and I can confirm from short experience; so we are not entering a mine field, it seems. First I thought along the lines that you point out in your how-to. Later I thought that we should not overload Fossil with options, especially as everybody will want something a little different. Instead, it should be the reverse proxy that does all the work IMHO. How about using request headers for this? The reverse proxy could add two custom headers to the forwared request (similar to X-Forwarded-For): - X-Fossil-Baseurl - X-Fossil-Repository Fossil would only look at these when in server mode. The first would specify the baseurl that is used to relocate all references in html/css output, and in redirect responses. If no such header exists, it is root ('/'). The first is sufficient for reverse proxying. The second would specify the repository to use for that request only. If no such header exists, it is the repository specified on the command line. This would take care of your generalised repository access. This would work very well with my own (soon to be published, GPL'ed) reverse proxy. It would also work very well with Lighttpd, using its mod_magnet module. Would it be workable with Apache too? (I'm not familiar with Apache configuration). Paul On Thu, 28 Jan 2010 11:53:36 -0800, Kyle McKay mack...@gmail.com wrote: Paul, I'm running a fossil server behind an Apache reverse proxy quite happily. I've been meaning to add something to the wiki cookbook about this but just haven't got around to it yet. I'm doing this because: 1. I want a fossil UI to be always on and available via my web server 2. I want the fossil server to run as a different user account than the web server processes 3. I don't want to use any suid programs (i.e. suExec) My apache web server is setup so that: http://my_server_name/fossil Is reverse proxied to the fossil server process that is running as a daemon on a separate port http://my_server_name/anything-other-than-fossil-here Serves up whatever else would normally be served on my server. To make this work (I'm running on Darwin which is very Unix like) you need to do these two things (the examples assume you have a bash shell): 1. Start your fossil server daemon running with a shell script like this #!/bin/sh export SCRIPT_NAME=/fossil fossil server -P 8000 full_path_to_fossil_respository_here If you want to start the fossil server in its own process group, add this line: set -m at the beginning of the script and add this line: disown at the end and you probably want to redirect fossil input, output and error to /dev/null as well so the final script to do all of this would look like (adding nohup also to make it immune to SIGHUP): #!/bin/bash set -m export SCRIPT_NAME=/fossil nohup fossil server -P 8000 full_path_to_fossil_respository_here \ /dev/null /dev/null 21 disown # this is a bashism 2. Add this configuration section to your Apache configuration ProxyPass /fossil http://machine_your_fossil_server_is_running_on: 8000 ProxyPreserveHost On # ProxyPreserveHost is required since fossil inspects the Host value # and without it fossil-generated links will point directly to fossil # instead of the Apache server 3. Access your fossil server like this: http://machine_apache_is_running_on/fossil 4. Optionally add a firewall rule to limit connections to the fossil server to only those coming from the Apache server machine (be nice if
Re: [fossil-users] Fossil behind reverse proxy
On Jan 30, 2010, at 04:00, Paul Ruizendaal wrote: Hi Kyle, In the default admin setup, the logo path needed to be fixed from '/logo' to '$baseurl/logo', but then it works fully. I didn't need to do that. Must have been fixed in later versions of fossil. That would be a bug for the cgi command as well. My new repositories already had that correct without needing to edit anything. I can confirm that it also works on Linux and Windows, not just Darwin. For folks not using Apache it would be good if your below 'how to' could mention that the reverse proxy needs to strip the baseurl of the uri it forwards to the Fossil server (i.e.: '/fossil/index' must be forwarded as '/index'). That is standard behavior for a reverse proxy as the proxy machine the requests are being sent to has absolutely no knowledge of where it's being mapped into the other machine's web space or even that it's being used as a proxy in the first place (unless it starts inspecting X-Forwarded-... and/or Via headers). Normally in this situation, however, you would expect that content coming from the proxy machine would have to be inspected and have any contained links rewritten to match the other machine's web space (mod_proxy_html can do this http://apache.webthing.com/mod_proxy_html/ ) and indeed I had it working using mod_poxy_html when I realized it wasn't necessary. I prefer to avoid the extra overhead of inspecting the content since it's not necessary if you set SCRIPT_NAME (with the proviso that you mention below that you can no longer access it directly if you do this). However, this is a hack that works by accident. It works because 'server' and 'cgi' share code paths and the 'server' code flow reads part of the CGI environment even though it shouldn't. Yes but unless the current fossil architecture is changed it will keep working. It's also fortunate that SCRIPT_NAME is used when constructing the login cookie -- but again, for the cgi command to keep working it needs to. Can you imagine the configuration headache if one had an unrelated SCRIPT_NAME environment variable and wasn't aware of this feature... I was a bit surprised that SCRIPT_NAME was used even when the GATEWAY_INTERFACE environment variable is not set. Probably SCRIPT_NAME should only be used if GATEWAY_INTERFACE is CGI/1.0 or later. But even then that would just mean you needed to set that variable together with SCRIPT_NAME to use the hack. Also, the hack fixes the baseUrl to one defined prefix. Access to a fossil server setup using this hack becomes unusable from the web if accessed directly as well, nor can multiple baseurl's be mapped to a single fossil server instance. Whilst I'm quite happy that the hack fixes my immediate problem, Yes, me too. I think a better engineered solution is preferrable. Undocumented behavior has a bad habit of breaking or going away -- a documented solution is preferred. How about using request headers for this? The reverse proxy could add two custom headers to the forwared request (similar to X-Forwarded-For): - X-Fossil-Baseurl - X-Fossil-Repository Fossil would only look at these when in server mode. Or in http mode. The first would specify the baseurl that is used to relocate all references in html/ css output, and in redirect responses. Using the SCRIPT_NAME hack and running in server mode, you do have to make sure that Location: redirects get corrected -- as you say, a reverse proxy can be expected to do this -- this is never necessary when running in cgi mode. It might be a bit of a challenge to catch all the redirects unless you hack it by prepending SCRIPT_NAME to the value stuffed into REQUEST_URI by the source in server and http modes. This line in cgi.c (in the cgi_handle_http_request function): cgi_setenv(REQUEST_URI, zToken); would need to change to set REQUEST_URI to the contents of SCRIPT_NAME concatenated to zToken instead of what it does now. That would make the SCRIPT_NAME hack produce correct redirects and I believe make a SCRIPT_NAME hack running server be directly accessible. Something like this but without the memory leak or double getenv call: cgi_setenv(REQUEST_URI, mprintf(%s%s, (getenv(SCRIPT_NAME)? getenv(SCRIPT_NAME):), zToken)); This would work very well with my own (soon to be published, GPL'ed) reverse proxy. It would also work very well with Lighttpd, using its mod_magnet module. Would it be workable with Apache too? (I'm not familiar with Apache configuration). The updated Apache 2 configuration to reverse proxy a fossil server running like this: export SCRIPT_NAME=/fos fossil server -P 8080 /path/to/some/fossil/repository is this: RewriteEngine On RewriteRule ^/fos$ /fos/ [PT] ProxyPreserveHost On ProxyPass /fos/ http://machine_running_fossil_server:8080/ Location /fos/ ProxyPassReverse / RequestHeader set
Re: [fossil-users] Fossil behind reverse proxy
Paul, I'm running a fossil server behind an Apache reverse proxy quite happily. I've been meaning to add something to the wiki cookbook about this but just haven't got around to it yet. I'm doing this because: 1. I want a fossil UI to be always on and available via my web server 2. I want the fossil server to run as a different user account than the web server processes 3. I don't want to use any suid programs (i.e. suExec) My apache web server is setup so that: http://my_server_name/fossil Is reverse proxied to the fossil server process that is running as a daemon on a separate port http://my_server_name/anything-other-than-fossil-here Serves up whatever else would normally be served on my server. To make this work (I'm running on Darwin which is very Unix like) you need to do these two things (the examples assume you have a bash shell): 1. Start your fossil server daemon running with a shell script like this #!/bin/sh export SCRIPT_NAME=/fossil fossil server -P 8000 full_path_to_fossil_respository_here If you want to start the fossil server in its own process group, add this line: set -m at the beginning of the script and add this line: disown at the end and you probably want to redirect fossil input, output and error to /dev/null as well so the final script to do all of this would look like (adding nohup also to make it immune to SIGHUP): #!/bin/bash set -m export SCRIPT_NAME=/fossil nohup fossil server -P 8000 full_path_to_fossil_respository_here \ /dev/null /dev/null 21 disown # this is a bashism 2. Add this configuration section to your Apache configuration ProxyPass /fossil http://machine_your_fossil_server_is_running_on: 8000 ProxyPreserveHost On # ProxyPreserveHost is required since fossil inspects the Host value # and without it fossil-generated links will point directly to fossil # instead of the Apache server 3. Access your fossil server like this: http://machine_apache_is_running_on/fossil 4. Optionally add a firewall rule to limit connections to the fossil server to only those coming from the Apache server machine (be nice if fossil had a loopback-only setting similar to postfix's to bind its socket listener to only localhost IPv4/IPv6 interfaces). If you want your fossil URL to look like http://some_machine/foo/bar/ scm you need would change the above example lines for starting your fossil server and setting your Apache configuration as follows: SCRIPT_NAME=/foo/bar/scm ProxyPass /foo/bar/scm http:// machine_your_fossil_server_is_running_on:8000 Similarly you can change the port the fossil server runs on just as easily. It turns out that since fossil already handles running from an arbitrary web location as a cgi script, it quite happily will still use that arbitrary location when running as a server if you provide it via SCRIPT_NAME. I wish there was functionality something like this though: fossil server -P 8000 --ext .fsl path_to_directory_containing_.fsl_repositories Where a single fossil server could serve up multiple fossil repositories. You would just point it to the parent directory and tell it what repository extension to look for and then it would insert an additional element into the URL using the base name of the fossil repository minus the extension. So if you had these repositories on your system: /some/directory/repository1.fsl /some/directory/repository2.fsl And started the fossil server like this: fossil server -P 8080 --ext .fsl /some/directory Then you could access repository1.fsl like this: http://localhost:8080/repository1 and repository2.fsl like this: http://localhost:8080/repository2 and as a bonus you could get a list of available repositories with this: http://localhost:8080/ (And, of course, still use the SCRIPT_NAME trick to change the URL location if you like.) I believe a relatively simple Perl or Python server script could use the fossil http command to implement the multiple repository server relatively easily since the SCRIPT_NAME technique also works with the fossil http command. Hmmm, I might just have to write that script later today. Kyle On Jan 28, 2010, at 04:00, Paul Ruizendaal wrote: It may be subtler and easier than I first thought: Fossil already uses the host information from the Host: header, not from its own IP. When in CGI mode, it already relocates all its absolute references to include the prefix of the cgi script location. When running as server Fossil does not do the above relocation but keeps everyting based at root ('/'), regardless of the path in the request uri. Is there a reason that makes fossil CGI style relocation a bad idea for a fossil running in server mode? Paul == I just tried to put Fossil (running as server) behind a reverse proxy (home grown, but similar to Pound). That
[fossil-users] Fossil behind reverse proxy
I just tried to put Fossil (running as server) behind a reverse proxy (home grown, but similar to Pound). That doesn't work very well, because Fossil prefixes all paths in its output with a full baseURL (as seen by Fossil). The client can't use that as the reverse proxy maps an entirely different prefix to the Fossil server instance. I think the html/css output by Fossil should use relative paths, not absolute paths. Next to the above, also the 301 Redirect repsonses have the wrong url, but that is as per the http RFC: it is a reasonable job for a reverse proxy to rewrite the Location: header of a 301 response. Before I attempt this rather massive patch: Richard, any remarks? Paul ___ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users
[fossil-users] Fossil behind reverse proxy
It may be subtler and easier than I first thought: Fossil already uses the host information from the Host: header, not from its own IP. When in CGI mode, it already relocates all its absolute references to include the prefix of the cgi script location. When running as server Fossil does not do the above relocation but keeps everyting based at root ('/'), regardless of the path in the request uri. Is there a reason that makes fossil CGI style relocation a bad idea for a fossil running in server mode? Paul == I just tried to put Fossil (running as server) behind a reverse proxy (home grown, but similar to Pound). That doesn't work very well, because Fossil prefixes all paths in its output with a full baseURL (as seen by Fossil). The client can't use that as the reverse proxy maps an entirely different prefix to the Fossil server instance. I think the html/css output by Fossil should use relative paths, not absolute paths. Next to the above, also the 301 Redirect repsonses have the wrong url, but that is as per the http RFC: it is a reasonable job for a reverse proxy to rewrite the Location: header of a 301 response. Before I attempt this rather massive patch: Richard, any remarks? Paul ___ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users