Formatting uWSGI requests logs¶
uWSGI has a --logformat option for building custom request loglines. The syntax is simple:
[uwsgi]
logformat = i am a logline reporting "%(method) %(uri) %(proto)" returning with status %(status)
All of the variables marked with %() are substituted using specific rules. Three kinds of logvars are defined (“offsetof”, functions, and user-defined).
offsetof¶
These are taken blindly from the internal wsgi_request structure of the current request.
- %(uri) -> REQUEST_URI
- %(method) -> REQUEST_METHOD
- %(user) -> REMOTE_USER
- %(addr) -> REMOTE_ADDR
- %(host) -> HTTP_HOST
- %(proto) -> SERVER_PROTOCOL
- %(uagent) -> HTTP_USER_AGENT (starting from 1.4.5)
- %(referer) -> HTTP_REFERER (starting from 1.4.5)
functions¶
These are simple functions called for generating the logvar value:
- %(status) -> HTTP response status code
- %(micros) -> response time in microseconds
- %(msecs) -> response time in milliseconds
- %(time) -> timestamp of the start of the request
- %(ctime) -> ctime of the start of the request
- %(epoch) -> the current time in Unix format
- %(size) -> response body size + response headers size (since 1.4.5)
- %(ltime) -> human-formatted (Apache style) request time (since 1.4.5)
- %(hsize) -> response headers size (since 1.4.5)
- %(rsize) -> response body size (since 1.4.5)
- %(cl) -> request content body size (since 1.4.5)
- %(pid) -> pid of the worker handling the request (since 1.4.6)
- %(wid) -> id of the worker handling the request (since 1.4.6)
- %(switches) -> number of async switches (since 1.4.6)
- %(vars) -> number of CGI vars in the request (since 1.4.6)
- %(headers) -> number of generated response headers (since 1.4.6)
- %(core) -> the core running the request (since 1.4.6)
- %(vsz) -> address space/virtual memory usage (in bytes) (since 1.4.6)
- %(rss) -> RSS memory usage (in bytes) (since 1.4.6)
- %(vszM) -> address space/virtual memory usage (in megabytes) (since 1.4.6)
- %(rssM) -> RSS memory usage (in megabytes) (since 1.4.6)
- %(pktsize) -> size of the internal request uwsgi packet (since 1.4.6)
- %(modifier1) -> modifier1 of the request (since 1.4.6)
- %(modifier2) -> modifier2 of the request (since 1.4.6)
- %(metric.XXX) -> access the XXX metric value (see The Metrics subsystem)
- %(rerr) -> number of read errors for the request (since 1.9.21)
- %(werr) -> number of write errors for the request (since 1.9.21)
- %(ioerr) -> number of write and read errors for the request (since 1.9.21)
- %(tmsecs) -> timestamp of the start of the request in milliseconds since the epoch (since 1.9.21)
- %(tmicros) -> timestamp of the start of the request in microseconds since the epoch (since 1.9.21)
- %(var.XXX) -> the content of request variable XXX (like var.PATH_INFO, available from 1.9.21)
User-defined logvars¶
You can define logvars within your request handler. These variables live only per-request.
import uwsgi
def application(env, start_response):
uwsgi.set_logvar('foo', 'bar')
# returns 'bar'
print uwsgi.get_logvar('foo')
uwsgi.set_logvar('worker_id', str(uwsgi.worker_id()))
...
With the following log format you will be able to access code-defined logvars:
uwsgi --logformat 'worker id = %(worker_id) for request "%(method) %(uri) %(proto)" test = %(foo)'
Apache-style combined request logging¶
To generate Apache-compatible logs:
[uwsgi]
...
log-format = %(addr) - %(user) [%(ltime)] "%(method) %(uri) %(proto)" %(status) %(size) "%(referer)" "%(uagent)"
...
Hacking logformat¶
(Updated to 1.9.21)
You can register new “logchunk” (the function to call for each logformat symbol) with
struct uwsgi_logchunk *uwsgi_register_logchunk(char *name, ssize_t (*func)(struct wsgi_request *, char **), int need_free);
name is the name of the symbol
need_free if 1, means the pointer set by func must be free()d;
func the function to call in the log handler
static ssize_t uwsgi_lf_foobar(struct wsgi_request *wsgi_req, char **buf) {
*buf = uwsgi_num2str(wsgi_req->status);
return strlen(*buf);
}
static void register_logchunks() {
uwsgi_register_logchunk("foobar", uwsgi_lf_foobar, 1);
}
struct uwsgi_plugin foobar_plugin = {
.name = "foobar",
.on_load = register_logchunks,
};
if you load the foobar plugin, you will be able to use the %(foobar) request logging variable (reporting the request status)