feat: support array_value attribute type, closes #82

README.md

@@ -81,12 +81,16 @@ local cur_span_context = context:span_context()
 local attr = require("opentelemetry.attribute")
 -- string attribute
 attr.string("service.name", "openresty")
+attr.string_array("service.name", {"openresty"})
 -- int attribute
 attr.int("attr_int", 100)
+attr.int_array("attr_ints", {100, 1000})
 -- double attribute
 attr.double("attr_double", 10.24)
+attr.double_array("attr_doubles", {10.24, 20.48})
 -- bool attribute
 attr.bool("attr_bool", true)
+attr.bool_array("attr_bools", {true, false})
 ```
 
 ## Resource

examples/openresty/nginx.conf

@@ -91,6 +91,7 @@ server {
 
             local span_kind = require("opentelemetry.trace.span_kind")
 
+            local http_conv = require("opentelemetry.semantic_conventions.trace.http")
             local attr = require("opentelemetry.attribute")
             local context = require("opentelemetry.context").new()
             local trace_context_propagator = require("opentelemetry.trace.propagation.text_map.trace_context_propagator").new()
@@ -101,9 +102,17 @@ server {
             -- extract trace context from the headers of downstream HTTP request
             context = composite_propagator:extract(context, ngx.req)
 
+            local attributes = http_conv.request_header(ngx.req.get_headers())
+            table.insert(attributes, attr.string_array("attr_strings", {"opentelemetry", "lua"}))
+            table.insert(attributes, attr.int("attr_int", 1024))
+            table.insert(attributes, attr.int_array("attr_ints", {1024, 2048}))
+            table.insert(attributes, attr.double("attr_double", 10.24))
+            table.insert(attributes, attr.double_array("attr_doubles", {10.24, 20.48}))
+            table.insert(attributes, attr.bool("attr_bool", true))
+            table.insert(attributes, attr.bool_array("attr_bools", {true, false}))
             local context, span = tracer:start(context, "access_by_lua_block", {
                 kind = span_kind.internal,
-                attributes = {attr.double("attr_double", 10.24), attr.bool("attr_bool", true)},
+                attributes = attributes,
             })
             context:attach()
 
@@ -121,7 +130,10 @@ server {
             -- get tracer from current context
             local tracer = context.current():span():tracer_provider():tracer("opentelemetry-lua")
 
+            local http_conv = require("opentelemetry.semantic_conventions.trace.http")
+            local resp_attrs = http_conv.response_header(ngx.resp.get_headers())
             local context, sub_span = tracer:start(context.current(), "header_filter_by_lua_block")
+            sub_span:set_attributes(unpack(resp_attrs))
             sub_span:record_error("this is err")
             sub_span:set_status(span_status.ERROR, "set status err")
             sub_span:add_event("event1", {attributes = {attr.string("attr_string", "attr_value")}})

lib/opentelemetry/attribute.lua

@@ -9,6 +9,21 @@ function _M.string(key, value)
     }
 end
 
+function _M.string_array(key, values)
+    local ret = {
+        key = key,
+        value = {
+            array_value = {
+                values = {}
+            }
+        }
+    }
+    for i = 1, #values do
+        table.insert(ret.value.array_value.values, {string_value = values[i]})
+    end
+    return ret
+end
+
 function _M.int(key, value)
     return {
         key = key,
@@ -18,6 +33,21 @@ function _M.int(key, value)
     }
 end
 
+function _M.int_array(key, values)
+    local ret = {
+        key = key,
+        value = {
+            array_value = {
+                values = {}
+            }
+        }
+    }
+    for i = 1, #values do
+        table.insert(ret.value.array_value.values, {int_value = values[i]})
+    end
+    return ret
+end
+
 function _M.bool(key, value)
     return {
         key = key,
@@ -27,6 +57,21 @@ function _M.bool(key, value)
     }
 end
 
+function _M.bool_array(key, values)
+    local ret = {
+        key = key,
+        value = {
+            array_value = {
+                values = {}
+            }
+        }
+    }
+    for i = 1, #values do
+        table.insert(ret.value.array_value.values, {bool_value = values[i]})
+    end
+    return ret
+end
+
 function _M.double(key, value)
     return {
         key = key,
@@ -36,4 +81,19 @@ function _M.double(key, value)
     }
 end
 
+function _M.double_array(key, values)
+    local ret = {
+        key = key,
+        value = {
+            array_value = {
+                values = {}
+            }
+        }
+    }
+    for i = 1, #values do
+        table.insert(ret.value.array_value.values, {double_value = values[i]})
+    end
+    return ret
+end
+
 return _M

lib/opentelemetry/semantic_conventions/trace/http.lua

@@ -2,6 +2,8 @@
 -- See: https://github.com/open-telemetry/opentelemetry-specification/tree/main/specification/trace/semantic_conventions
 --
 -- module @semantic_conventions.trace.http
+local attribute   = require("opentelemetry.attribute")
+
 local _M = {
     -- HTTP request method.
     HTTP_METHOD = "http.method",
@@ -26,6 +28,49 @@ local _M = {
     -- The matched route (path template in the format used by the respective server framework). See note below
     HTTP_ROUTE = "http.route",
     -- The IP address of the original client behind all proxies, if known (e.g. from [X-Forwarded-For](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For)).
-    HTTP_CLIENT_IP = "http.client_ip"
+    HTTP_CLIENT_IP = "http.client_ip",
+    -- The opentelemetry attribute key prefix for HTTP request headers
+    HTTP_REQUEST_HEADER = "http.request.header",
+    -- The opentelemetry attribute key prefix for HTTP response headers
+    HTTP_RESPONSE_HEADER = "http.response.header",
 }
+
+------------------------------------------------------------------
+-- returns the contents of headers as OpenTelemetry attributes.
+--
+-- @headers     a table of HTTP request headers
+-- @return      a table of attribute
+------------------------------------------------------------------
+function _M.request_header(headers)
+    local attributes = {}
+    for k, v in pairs(headers) do
+        k = _M.HTTP_REQUEST_HEADER .. '.' .. k
+        if type(v) == "table" then
+            table.insert(attributes, attribute.string_array(k, v))
+        else
+            table.insert(attributes, attribute.string(k, v))
+        end
+    end
+    return attributes
+end
+
+------------------------------------------------------------------
+-- returns the contents of headers as OpenTelemetry attributes.
+--
+-- @headers     a table of HTTP response headers
+-- @return      a table of attribute
+------------------------------------------------------------------
+function _M.response_header(headers)
+    local attributes = {}
+    for k, v in pairs(headers) do
+        k = _M.HTTP_RESPONSE_HEADER .. '.' .. k
+        if type(v) == "table" then
+            table.insert(attributes, attribute.string_array(k, v))
+        else
+            table.insert(attributes, attribute.string(k, v))
+        end
+    end
+    return attributes
+end
+
 return _M