feat(metrics) switch metric name metadata separator to ':'

Switch from `.` to `:` since module names can contain dots, making the
prefix difficult to parse.

docs/METRICS.md

@@ -38,9 +38,9 @@ gauge, or a histogram.
 ## Name Prefixing
 
 To avoid naming conflicts between Proxy-Wasm filters, the name of a metric is
-always prefixed with: `pw.{filter_name}.{metric_name}`. This means that a metric
-named `a_counter` inserted by `a_filter` will have its name stored as:
-`pw.a_filter.a_counter`.
+always prefixed with colon-separated metadata: `pw:{filter_name}:`. This means
+that a metric named `a_counter` inserted by `a_filter` will have its name stored
+as: `pw:a_filter:a_counter`.
 
 Thus, the maximum length of a metric name configured via
 [max_metric_name_length] is enforced on the prefixed name and may need to be

lib/resty/wasmx/shm.lua

@@ -403,7 +403,7 @@ local function metrics_define(zone, name, metric_type, opts)
         end
     end
 
-    name = "lua." .. name
+    name = "lua:" .. name
 
     local cname = ffi_new("ngx_str_t", { data = name, len = #name })
     local m_id = ffi_new("uint32_t[1]")
@@ -528,12 +528,12 @@ end
 
 
 ---
--- ngx_wasm_module internally prefixes metric names according to
--- where they have been defined, e.g. "pw.filter.*", "lua.*", or
--- "wa.*".
+-- ngx_wasm_module internally prefixes metric names with colon-separated
+-- metadata indicating where they have been defined, e.g. "pw:a_filter:*",
+-- "lua:*", or "wa:".
 --
 -- metrics_get_by_name assumes it is retrieving a Lua-defined metric
--- and will by default prefix the given name with `lua.`
+-- and will by default prefix the given name with `lua:`
 --
 -- This behavior can be disabled by passing `opts.prefix` as false.
 local function metrics_get_by_name(zone, name, opts)
@@ -554,7 +554,7 @@ local function metrics_get_by_name(zone, name, opts)
     ffi_fill(_mbuf, _mbs)
     ffi_fill(_hbuf, _hbs)
 
-    name = (opts and opts.prefix == false) and name or "lua." .. name
+    name = (opts and opts.prefix == false) and name or "lua:" .. name
 
     local cname = ffi_new("ngx_str_t", { data = name, len = #name })
 

src/common/proxy_wasm/ngx_proxy_wasm_host.c

@@ -1635,7 +1635,7 @@ ngx_proxy_wasm_hfuncs_define_metric(ngx_wavm_instance_t *instance,
     }
 
     prefixed_name.data = buf;
-    prefixed_name.len = ngx_sprintf(buf, "pw.%V.%V", filter_name, &name)
+    prefixed_name.len = ngx_sprintf(buf, "pw:%V:%V", filter_name, &name)
                         - buf;
 
     rc = ngx_wa_metrics_define(metrics, &prefixed_name, type, NULL, 0, id);

t/04-openresty/ffi/shm/020-metrics_define.t

@@ -40,10 +40,10 @@ __DATA__
 ok
 --- error_log eval
 [
-    qr/.*? \[debug\] .*? defined counter "lua.c1" with id \d+/,
-    qr/.*? \[debug\] .*? defined gauge "lua.g1" with id \d+/,
-    qr/.*? \[debug\] .*? defined histogram "lua.h1" with id \d+/,
-    qr/.*? \[debug\] .*? defined histogram "lua.ch1" with id \d+/,
+    qr/.*? \[debug\] .*? defined counter "lua:c1" with id \d+/,
+    qr/.*? \[debug\] .*? defined gauge "lua:g1" with id \d+/,
+    qr/.*? \[debug\] .*? defined histogram "lua:h1" with id \d+/,
+    qr/.*? \[debug\] .*? defined histogram "lua:ch1" with id \d+/,
 ]
 --- no_error_log
 [error]

t/04-openresty/ffi/shm/025-metrics_get_by_name.t

@@ -12,7 +12,7 @@ run_tests();
 __DATA__
 
 === TEST 1: shm_metrics - get_by_name() sanity FFI-defined metrics
-prefix: lua.*
+colon-separated prefix: "lua:*"
 --- valgrind
 --- metrics: 16k
 --- config
@@ -51,7 +51,7 @@ ch1: {sum=2,type="histogram",value={{count=0,ub=1},{count=1,ub=3},{count=0,ub=5}
 
 
 === TEST 2: shm_metrics - get_by_name() sanity non-FFI-defined metrics
-prefix: pw.hostcalls.*
+colon-separated prefix: "pw:hostcalls:*"
 --- wasm_modules: hostcalls
 --- config eval
 my $record_histograms;
@@ -84,9 +84,9 @@ qq{
             local shm = require "resty.wasmx.shm"
             local pretty = require "pl.pretty"
 
-            ngx.say("c1: ", pretty.write(shm.metrics:get_by_name("pw.hostcalls.c1", { prefix = false }), ""))
-            ngx.say("g1: ", pretty.write(shm.metrics:get_by_name("pw.hostcalls.g1", { prefix = false }), ""))
-            ngx.say("h1: ", pretty.write(shm.metrics:get_by_name("pw.hostcalls.h1", { prefix = false }), ""))
+            ngx.say("c1: ", pretty.write(shm.metrics:get_by_name("pw:hostcalls:c1", { prefix = false }), ""))
+            ngx.say("g1: ", pretty.write(shm.metrics:get_by_name("pw:hostcalls:g1", { prefix = false }), ""))
+            ngx.say("h1: ", pretty.write(shm.metrics:get_by_name("pw:hostcalls:h1", { prefix = false }), ""))
         }
     }
 }

t/04-openresty/ffi/shm/026-metrics_iterate_keys.t

@@ -32,9 +32,9 @@ __DATA__
         }
     }
 --- response_body
-lua.c1
-lua.g1
-lua.h1
+lua:c1
+lua:g1
+lua:h1
 --- no_error_log
 [error]
 [crit]

t/04-openresty/ffi/shm/027-metrics_get_keys.t

@@ -30,9 +30,9 @@ __DATA__
         }
     }
 --- response_body
-lua.c1
-lua.g1
-lua.h1
+lua:c1
+lua:g1
+lua:h1
 --- no_error_log
 [error]
 [crit]