October 2011 - syslog-ng - lists.balabit.hu

syslog-ng 3.2.4 MySQL connection loss Server has gone away
by Erik Maciejewski 12 Nov '11

12 Nov '11

Hello, I have been researching an issue with syslog-ng 3.2.4 (both the Linux glibc2.3.6 and platform independent compiled from source versions) and MySQL on CentOS 5.6 in which syslog-ng tries to insert a log messages using a dead TCP or unix socket connection to a MySQL database. The issue results in the max attempt to insert a log message and then the message subsequently dropped. This seems to occur regularly in predominately low message volume environments, but has the potential to affect all environments using a MySQL (or other db) destination. The root cause of the issue seems to be directly related to the health of the connection between syslog-ng and MySQL and can be affected by the "wait_timeout" value used by MySQL to kill off inactive connections. I want to provide justification for implementing a fix to syslog-ng as I believe manipulating a, possibly tuned, environment variable for MySQL would seem like the wrong approach to take for remedial action. I feel that many MySQL instances are implemented in shared environments and are themselves shared by many applications. New connections to a MySQL instance are generally regarded as low cost and, it would seem, more often than not never used in a persisted fashion when supporting distributed applications. That being said, many times the "wait_timeout" value is set very low so that the MySQL instance can effectively control the number of simultaneous connections. By taking somewhat of a black-box approach to the issue (I'm just starting to explore syslog-ng), I noticed that there doesn't seem to be any health checking of the TCP or unix socket connection in the SQL destination implementation after the initial connection is made (most of the db actions being abstracted away by libdbi). Even if a syslog-ng database thread is suspended and reactivated due to error, there does not seem to be any attempt to check the health of the database connection. I have implemented a fix in my compiled version that will check a database connection's health and attempt to reconnect upon discovering a dead connection. I would like to know the policies/procedures/best practices for submitting such issues and/or fixes for discussion, review, and implementation. If this is a known issue or I am just wrong, all the better! Thank you guys for keeping this project going and I'm looking forward to implementing syslog-ng in a production environment in the very near future! Regards, Erik Maciejewksi

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Problems writing to files with different templates/ownership in 3.x
by Brian De Wolf 12 Nov '11

12 Nov '11

Hello, I'm using syslog-ng as a remote syslog server for several of our internal groups. As such, when a syslog arrives, I use the source address to determine the ownership of the log file. Here is how I'm currently doing this: source net { udp(ip(0.0.0.0), port(514) flags(no-multi-line)); }; filter examplefilter { netmask("10.0.0.0/255.255.0.0"); }; filter example2filter { netmask("192.168.0.0/255.255.0.0"); }; destination examplelog { file("/var/log/remote/$HOST.log" group(examplegroup)); }; destination example2log { file("/var/log/remote/$HOST.log" group(example2group)); }; log { source(net); filter(examplefilter); destination(examplelog); flags(final); }; log { source(net); filter(example2filter); destination(example2log); flags(final); }; This worked fine in 1.6.x and appears to work fine in 3.2.x, but when logrotate pokes syslog-ng I get lines like this: syslog-ng: Internal error, duplicate configuration elements refer to the same persistent config; name='affile_dd_writers(/var/log/remote/$HOST.log)' Is there a better way to do this which only produces one reference to "/var/log/remote/$HOST.log"? Also, I'm using a similar set of filters and destinations to apply different templates to text that is being written to a single file. This also produces the error, but I am more concerned that the combined file might experience issues if the config isn't supposed to have multiple destinations be the same location. Is there a way to use filters to apply templates while still only having one destination defined? Could my current setup result in lost log lines? Thanks, Brian

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Loganalyzer
by Peter Czanik 11 Nov '11

11 Nov '11

Hello, Recently I found many e-mail and forum posts looking for a web GUI for syslog-ng. One of them, Loganalyzer is getting more popular, as a completely free web application. There is just one catch, it was not designed for syslog-ng originally. So I did some research and tests, and using my instructions quite easy to get started with it. Of course Loganalyzer has some rough edges, but it works for me on a number of different systems. For a step by step tutorial to get started, read my blog at http://czanik.blogs.balabit.com/2011/02/loganalyzer/ Have a nice weekend! Bye, -- Peter Czanik (CzP) <czanik(a)balabit.hu> BalaBit IT Security / syslog-ng upstream http://czanik.blogs.balabit.com/

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Cannot start syslog-ng on Debian
by Hery Fanomezantsoa 07 Nov '11

07 Nov '11

I installed syslog-ng-3.2.4 from source on Debian Lenny and when I start syslog-ng with /usr/local/syslog-ng/sbin/ syslog-ng it shows me this error: Error creating persistent state file; filename='/usr/local/syslog-ng/var/syslog-ng.persist-', error='No such file or directory (2)' Can someone help me please?

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3.2.5 preparations
by Balazs Scheidler 04 Nov '11

04 Nov '11

Hi, I wanted to publish a last maintenance release from the 3.2 branch before moving on to work on 3.4. I've backported the relevant patches, tests have ran (both on my development computer and a separate build environment), but I'd like to ask anyone running 3.2.x to test it in more production-like environments. The current state is available in git, but I've also uploaded a tarball to: http://people.balabit.hu/bazsi/syslog-ng-3.2.4+20111022+0801.tar.gz These patches were applied since 3.2.4: 4f27ef33af4d84a31f237469e493ddd3834404fe nvtable: implement proper limitation on NVTable size b6136da08fb3421239a1c2dc40b582a5a7a2e78b gprocess: Implement stricter CAP_SYSLOG checking. 7e1a3903c0635a9a5070a6998ebc3f4e1282f33e syslogformat: handle AIX style message forwards properly 304539186bab96254d683b3026a00d5404903252 cfg_persist_config_add_entry(): call destroy notify if persist config is empty 409304c6fdcabbd1c321d57e2bbbd3d412a43cf2 cfg-lexer.c: don't include hidden files when including a directory 7ca0e8d65048b65fe3c0015ffc7ac8d73a234833 timezone format: handle half hours in the negative range properly e9dfe15a804610def3186f104853cc5626adbf53 Copyright fixups 320e4d065df521a61ff000e848f1e6a7a787c616 program-override(): disable the effect of store-legacy-msghdr flag ef4a0ff535f2860036d8901b290b204aca7568fa persist-state: fixed a memory small leak fc91010594fe80ba111020f1bb4e23ef41acfdc6 cfg-lexer: closed a memory leak in token blocks handling 9f2153fdb3d9b9cdc120af85db5e87f93cbcec0b PCRE matcher: free the pointer returned by pcre_study() to close a memory leak 2884c8fa188ec1ab8e09799b9c6d497cf8aa423f blocks: propagate include problems as parser errors c2669ffeeae0825c9de637c04794dcfa3965b3de logmatcher: fixed a possible crash in case a regexp match is applied to a read-only macro a2fdfc9ee73c1def081eed0c554c592fd6bea572 [SCL] set empty default parameter to block ce2d45f63b9b2ee7b3b486e517b92662158c321d logproto: fixed an inbalanced get_state()/put_state() pair 3e9be2596c298e31a3b3478c430d517f5bfe42c9 [lex-rules.am]: rules use $(EGREP) instead of grep -E.(EGREP is -E compliant grep implementati b00fde64d08642eb06e1cc342f1c762a7dde6767 afsocket: Fixed a wrong cast in afsocket_dd_set_keep_alive(). 5490cf73b95a597c8695407c875cf55d23679bb9 [plugin] on AIX syslog-ng try to load .a archive modules e98032d07cdcb3a51fe1a7ddda3d3d24b0985a92 zone_info_parser: move variable declaration to the beginning of the function 88596d2b069bcdc46e207487be398ef31aa0aad9 tlscontext: fixed a possible segfault in certificate validation 160e7ebe5e6bd2ef1b0c0e79563d617c3f6f0065 [SDATA] Allow store sdata section without name or value 8bcab2e198863847036809c765b5415371d34760 afprog: automatically close pipes to child programs when executing external programs cd47492eb7733c443bccac4891efc398ab393a62 [syslog-ng-ctl] Added GLIB check version 81e350e410344e3eb1b79464359aa838507bf56a func_test: improve SQL autodetection e138c672b11eee0b30f5036872f0866dbaa6e255 system(): Bail out on unknown systems, and use a clean environment to generate config. 32650278fb35fb6f82522df54014c8d57f1705aa [persist]: only check the buffer size if no encoding is specified 2dc66883f722709b50e30875f8bb64daf24536ca LogProtoBufferedServer: fixed error handling in case the persist-state cannot be restored a4ff6764e06d7ae9eeaab8b9a89336680362ebb1 gprocess: fixed compilation error on old glibc versions f69ded4f05ddb1afcdf0ffbf3e16f1fbe3d6b53a func_test: make it possible to check whether it makes sense to run a testcase ae0ff59d9a761c2fda8a19b0c05e0e05c59bae57 Use CAP_SYSLOG instead of CAP_SYS_ADMIN, if available. f54686441496ded775877e33ad2c3e0310861b7b logreader flags: fixed segfault on unknown flags e2961e1c738c8b02ca6057ac34415536830dd0e9 add support for installing systemd unit files 2db971fc37471e39f6a8b34595ca23833166831e fixed chain-hostnames() processing 2f214c4f87d944aa28d53e331a67b1fd88d9840f systemd: make sure the acquired fd is in non-blocking mode I intend to wait a couple of days to do the actual release, but I'll proceed in a week or so without feedback too. -- Bazsi

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RFC/RFH: JSON status report and plans
by Gergely Nagy 03 Nov '11

03 Nov '11

Hi! To support CEE[1] stuff better, a few things are needed for syslog-ng's JSON support, and I'd like to take this opportunity to both give a headsup on what's still needed, and present a few easy bits that we need, and are very low hanging fruits for aspiring syslog-ng hackers to grab. Whitespace ---------- First of all, for compactness, the JSON we generate should be free of any unneccessary whitespace. At the moment, we generate JSON like this: { "foo": "bar", "baz": "quux" } The whitespace between key and value should be dropped, so should the whitespace at the curly brackets, so that we'd generate the following instead: {"foo":"bar","baz":"quux"} This is fairly trivial to fix, at least when using json-c (and that's the only case we need fixed, for other reasons): * Each json_object struct has a ->_to_json_string, which is used to format the string. * The default implementation puts in whitespace * The fix is: + #include <json_object_private.h> + copy the json_object_object_to_json_string() function from json.c, changing it to not emit extra whitespace + Override the ->to_json_string of the root JSON object in syslog-ng's modules/tfjson/tfjson.c's tf_json_append(), so that it points to the new function that doesn't do whitespace. This is a trivial patch, and I pretty much already wrote it for you. If someone can turn that into a patch, that would be grand! Nested JSON ----------- Another thing that would be very good to have, and not only for JSON, but for the MongoDB driver aswell, is to be able to generate nested objects. So that a key-value pair like "foo.bar"="quux" would end up as {"foo":{"bar":"quux"}} when formatted as JSON. That is, we'd need to split up keys by "." chars, and treat the first piece as the parent object. The harder part is that keys are not ordered within syslog-ng, and there might be conflicts (ie, syslog-ng allows "foo" and "foo.bar" to coexist, but we can't format that as JSON if we split by dots, because foo would then be a string and an object at the same time), which need to be handled one way or the other. My idea was that we could sort the keys in descending order, so that if we have "foo.aaa", "foo.bbb", and "foo", we'd end up with "foo.bbb", "foo.aaa", and "foo" list, split them up at the dots, pack stuff into foo, notice later that we already have a foo object, so a foo string is no-no, and threw a hissy fit (an error, that is). I'm not going to explain the whole algorithm here, but it's not too hard to figure it out. The question in this case is two-fold: anyone up for implementing this (I can provide assistance)? And if not, should this nesting be enabled by default? Should it be an option at all, or the only supported way? (I tend to side with going with nesting and not providing an option to disable it, but I can be persuaded otherwise) JSON parser ----------- Another thing that's reasonably easy to put together, is a JSON parser. Something like the existing CSV and patterndb parsers, except this would parse JSON with the json-c library. I have a few rough ideas, and am happy to provide help if someone feels up to the task of tackling this and developing the feature. =) Other pending issues -------------------- There's also a case for types. It would be beneficial if numbers could be represented as, well, numbers in the generated JSON (and similary, stored as numbers when using the MongoDB destination). This, however, requires some deeper changes, and I'm not yet familiar with that part of the code yet, either. So I'm not going to go into details. Nevertheless, I felt I need to mention this here, so that it won't fall under the table. [1]: http://cee.mitre.org/ -- |8]

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[Bug 96] New: pdbtool misleading error message
by bugzilla＠bugzilla.balabit.com 01 Nov '11

01 Nov '11

https://bugzilla.balabit.com/show_bug.cgi?id=96 Summary: pdbtool misleading error message Product: syslog-ng Version: 3.2.x Platform: PC OS/Version: Linux Status: NEW Severity: normal Priority: unspecified Component: syslog-ng AssignedTo: bazsi(a)balabit.hu ReportedBy: czanik(a)balabit.hu Type of the Report: --- Estimated Hours: 0.0 When trying to test a non-existent file with pdbtool it gives misleading error messages and even calls an external application before failing. czanik@linux-6y8u:~/patterndb> pdbtool test --validate uw-imapd.ceee uw-imapd.ceee: Unable to detect patterndb version, please write the <patterndb> tag on a single line warning: failed to load external entity "/usr/share/syslog-ng/xsd/patterndb-0.xsd" Schemas parser error : Failed to locate the main schema resource at '/usr/share/syslog-ng/xsd/patterndb-0.xsd'. WXS schema /usr/share/syslog-ng/xsd/patterndb-0.xsd failed to compile warning: failed to load external entity "uw-imapd.ceee" uw-imapd.ceee: xmllint returned an error, the executed command was: xmllint --noout --nonet --schema /usr/share/syslog-ng/xsd/patterndb-0.xsd uw-imapd.ceeeError opening classifier configuration file; filename='uw-imapd.ceee', error='No such file or directory (2)' I think, that the proper behavior would be, that pdbtool detect that the file is nonexistent, prints a message about it (without any other misleading messages) and quits without calling external apps. -- Configure bugmail: https://bugzilla.balabit.com/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are watching all bug changes.

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[PATCH 0/3]: Scratch buffers for syslog-ng 3.4
by Gergely Nagy 31 Oct '11

31 Oct '11

Following this mail will come three patches: * One to implement scratch buffers * Another to convert jsonparser to scratch buffers * And a third to convert value-pairs While the implementation works for me (with threaded(yes) and threaded(no) aswell), and I believe it to be correct, there's one thing I'm not quite sure about. But before I get there, let me try to explain how this simple thing is supposed to work! As Bazsi suggested, there are three methods: scratch_buffer_acquire(), scratch_buffer_release(), and scratch_buffers_reset(). All of them work with a thread-local GTrashStack, because my idea was that instead of trying to keep a list of available and used scratch buffers, we'll just store them in a stack, and leave it up to the scratch buffer users to return the buffers properly. This makes the implementation super simple, at the cost of not holding the hands of the scratch users. I believe that's an acceptable compromise. scratch_buffer_acquire() tries to pop an element from the stack, and if there's none, it creates a new one, and returns that. It also takes care of truncating the string to zero length. scratch_buffer_release() simply pushes an element onto the stack. scratch_buffers_reset() pops all elements from the stack, frees up both the GString contained within them, and the scratch buffer itself. Due to the way GTrashStack works, I introduced a new typedef: ScratchBuffer. The first element is a GTrashStack, which users need not care about, the second is the GString. ScratchBuffers are supposed to be used something like this: void test_scratchbuffer (void) { ScratchBuffer *sb = scratch_buffer_acquire(); g_string_printf(sb->s, "Hello %s!", "World"); /* Do something with sb->s */ scratch_buffer_release (sb); } There's one other trick in the implementation, however, and this is the one I'm unsure about: in order to avoid leaking madly, the thread-local scratch buffers MUST be destroyed when a thread finishes. This must also be done at the lowest level possible, to not litter the code with scratch_buffers_reset() calls. I did this with calling scratch_buffers_reset() at the end of main_loop_io_worker_job_start(), after all the finish callbacks have finished already. My reading of the code was that this is the place where threads are already finished, and they won't be needing scratch buffers anymore, and they should have released all of them aswell. All three patches are available on the feature/3.4/scratch-buffers branch of my github tree[0] too. While this is for 3.4, they should apply cleanly to 3.3 aswell (except for the jsonparser part, of course). [0]: https://github.com/algernon/syslog-ng/tree/feature/3.4/scratch-buffers

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[PATCH 0/1]: json-parser()
by Gergely Nagy 31 Oct '11

31 Oct '11

Following this mail, a bigger patch will be sent, that implements a JSON parser - a fairly simple one, for now. I did not want to explain every little detail in the commit message, so this umbrella mail is sent first, with a few details that cannot be found in the commit message (there will be some overlap, though). This patch (and any further developments I make in the future, until the parser is merged) will be available on the feature/3.3/json/parser branch of my new and shiny git tree[1], as soon as I push it out. [1]: git://github.com/algernon/syslog-ng.git First of all, here's a little code snippet that shows how to use the module: ,----[ syslog-ng.conf ] | @module tfjson | @module jsonparser | | source s_json { tcp(port(12345) flags(no-parse)); }; | destination d_json { | file("/var/log/messages.json" | template("$(format-json --scope dot-nv-pairs)\n")); | }; | parser p_json { json-parser(prefix(".json.")); }; | log { source(s_json); parser(p_json); destination (d_json); }; `---- With this config, we can send logs to this source as follows: ,----[ shell ] | $ echo '{"string": "this is a string!\\n\\nmultiline!", "int": 42, "double": 3.14 }' | nc localhost 12345 `---- And 'lo and behold, the destination looks like this: ,----[ /var/log/messages.json ] | {".json.string":"this is a string!\n\nmultiline!",".json.int":"42",".json.double":"3.140000"} `---- Since syslog-ng stores every value as a string, they will all be converted to strings. At some point in the future, when we can also store types, this information will be transmitted through, and format-json will preserve the types. For now, the parser has only one optional parameter: prefix(). I think you can figure out what it does. I think this is pretty darn cool as it is! Now, lets get down to the gory implementation details, as I'm sure you're all very interested in that! At the core, we have a LogJSONParser structure, which holds the configuration (hi, gchar *prefix!), and two GStrings, that are used over and over again during processing. The reason these two GStrings (serialized.key and serialized.value) are there, is to have as few memory allocations as possible: so we allocate the strings once, and reuse them over and over again. We also have a JSON tokener here, for similar reasons. Parsing itself is delegated to json-c, and all the parser does is iterate over the parsed object's keys, coerce them into strings, prepare a key (based on prefix and the parsed key), and store them in a LogMessage. Then we're done. Yes, really. The rest is boilerplate. Of course, life ain't that simple. For now, there's a bug where the JSON can't be parsed, we honour that with a tasty segmentation fault. This will be fixed at a later time.

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preparations for 3.3.2
by Balazs Scheidler 31 Oct '11

31 Oct '11

Hi, Since there are a nice number of fixes accumulated on the 3.3 tree, I'd like to prepare for the 3.3.2 release. Before doing the actual release though, I'd appreciate any kind of feedback you can give. The current state is in git right now, I'll try to create a timestamped tarball later this weekend. Thanks. -- Bazsi

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