feat: allow sending headers upstream returned by OPA server

apisix/plugins/opa.lua

@@ -19,6 +19,7 @@ local core   = require("apisix.core")
 local http   = require("resty.http")
 local helper = require("apisix.plugins.opa.helper")
 local type   = type
+local ipairs = ipairs
 
 local schema = {
     type = "object",
@@ -37,6 +38,14 @@ local schema = {
             description = "timeout in milliseconds",
         },
         keepalive = {type = "boolean", default = true},
+        send_headers_upstream = {
+            type = "array",
+            minItems = 1,
+            items = {
+                type = "string"
+            },
+            description = "list of headers to pass to upstream in request"
+        },
         keepalive_timeout = {type = "integer", minimum = 1000, default = 60000},
         keepalive_pool = {type = "integer", minimum = 1, default = 5},
         with_route = {type = "boolean", default = false},
@@ -125,6 +134,14 @@ function _M.access(conf, ctx)
         end
 
         return status_code, reason
+    else if result.headers and conf.send_headers_upstream then
+        for _, name in ipairs(conf.send_headers_upstream) do
+            local value = result.headers[name]
+            if value then
+                core.request.set_header(ctx, name, value)
+            end
+        end
+        end
     end
 end
 

ci/pod/opa/example.rego

@@ -29,6 +29,11 @@ allow {
     request.query["user"]
 }
 
+allow {
+    request.method == "GET"
+    startswith(request.path, "/echo")
+}
+
 reason = users[request.query["user"]].reason {
     not allow
     request.query["user"]
@@ -39,6 +44,11 @@ headers = users[request.query["user"]].headers {
     request.query["user"]
 }
 
+headers = {"user": request.query["user"]} {
+    allow
+    request.query["user"]
+}
+
 status_code = users[request.query["user"]].status_code {
     not allow
     request.query["user"]

t/plugin/opa.t

@@ -179,3 +179,47 @@ test-header: only-for-test
 --- error_code: 403
 --- response
 {"code":40001,"desc":"Give you a object reason"}
+
+
+
+=== TEST 12: setup route with plugin
+--- config
+    location /t {
+        content_by_lua_block {
+            local t = require("lib.test_admin").test
+            local code, body = t('/apisix/admin/routes/1',
+                 ngx.HTTP_PUT,
+                 [[{
+                        "plugins": {
+                            "opa": {
+                                "host": "http://127.0.0.1:8181",
+                                "policy": "example",
+                                "send_headers_upstream": ["user"]
+                            }
+                        },
+                        "upstream": {
+                            "nodes": {
+                                "127.0.0.1:1980": 1
+                            },
+                            "type": "roundrobin"
+                        },
+                        "uris": ["/echo"]
+                }]]
+                )
+
+            if code >= 300 then
+                ngx.status = code
+            end
+            ngx.say(body)
+        }
+    }
+--- response_body
+passed
+
+
+
+=== TEST 13: hit route
+--- request
+GET /echo?test=1234&user=none
+--- response_headers
+user: none