That would definitely be more useful, although it would also require rewriting a lot of the code around how log variables are interpolated. Right now, it looks like interpolation is pretty tightly tied to the actual act of logging (the build_logline function is pretty attached to the idea of having an active session available, and I think it'd be a lot of work to detangle it into a "build_logline_from_backend" that just took a backend or somesuch).
On Thu, Oct 22, 2015 at 2:37 AM, Baptiste <[email protected]> wrote: > On Thu, Oct 22, 2015 at 3:59 AM, James Brown <[email protected]> wrote: > > Hello haproxy@: > > > > My name is James Brown; I wrote a small piece of software called hacheck > > (https://github.com/Roguelazer/hacheck) which is designed to be a > healthcheck > > proxy for decentralized load balancer control (remove a node from a load > > balancer without knowing where the load balancers are; helpful once you > > start to have a truly, stupidly large number of load balancers). > > > > I am interested in using agent-checks instead of co-opting the existing > > httpchk mechanism; unfortunately, it looks like there's no convenient > way to > > multiplex multiple services onto a single agent-port and reasonably > > disambiguate them. For example, it'd be great if I could have a server > which > > runs one agent-check responder and can `MAINT` any of a dozen (or a > hundred) > > different services running on this box. > > > > I've attached a small patch which adds a new server parameter > (agent-send) > > which is a static string which will be sent to the agent on every server. > > This allows me to generate configs that look like > > > > backend foo > > server web1 10.1.2.1:8001 agent-check agent-port 3334 > agent-send "foo/web1\n" > > server web2 10.1.2.2:8001 agent-check agent-port 3334 > agent-send "foo/web2\n" > > > > backend bar > > server web1 10.1.2.1:8002 agent-check agent-port 3334 > agent-send "bar/web1\n" > > server web2 10.1.2.2:8002 agent-check agent-port 3334 > agent-send "bar/web2\n" > > > > And have a single service (running on port 3334) which can easily MAINT > or > > UP either "foo" or "bar" depending on the value that it receives. > > > > The patch seems to work in my limited testing (that is to say, HAProxy > sends > > the string and doesn't segfault or leak infinite amounts of RAM). > > > > Does this sound useful to anyone else? Is it worth upstreaming the > patch? I > > welcome your thoughts. > > -- > > James Brown > > Engineer > > EasyPost > > Hi James, > > This is interesting. > That said, I'm suggesting an improvement: use the log format varialble. > > So your configuration would become: > > backend foo > default-server agent-send "%b/%s\n" > server web1 10.1.2.1:8001 agent-check agent-port 3334 > server web2 10.1.2.2:8001 agent-check agent-port 3334 > > Baptiste > -- James Brown Engineer
