Provide stable config for agent/self (#3532)

* config: provide stable config for /v1/agent/self (#3530)

This patch adds a stable subset of the previous Config struct to the
agent/self response. The actual runtime configuration is moved into
DebugConfig and will be documented to change.

Fixes #3530

* config: fix tests

* doc: update api documentation for /v1/agent/self

agent/agent_endpoint.go

@@ -20,7 +20,8 @@ import (
 )
 
 type Self struct {
-	Config map[string]interface{}
+	Config      interface{}
+	DebugConfig map[string]interface{}
 	Coord       *coordinate.Coordinate
 	Member      serf.Member
 	Stats       map[string]map[string]string
@@ -51,8 +52,22 @@ func (s *HTTPServer) AgentSelf(resp http.ResponseWriter, req *http.Request) (int
 		return nil, acl.ErrPermissionDenied
 	}
 
+	config := struct {
+		Datacenter string
+		NodeName   string
+		Revision   string
+		Server     bool
+		Version    string
+	}{
+		Datacenter: s.agent.config.Datacenter,
+		NodeName:   s.agent.config.NodeName,
+		Revision:   s.agent.config.Revision,
+		Server:     s.agent.config.ServerMode,
+		Version:    s.agent.config.Version,
+	}
 	return Self{
-		Config: s.agent.config.Sanitized(),
+		Config:      config,
+		DebugConfig: s.agent.config.Sanitized(),
 		Coord:       cs[s.agent.config.SegmentName],
 		Member:      s.agent.LocalMember(),
 		Stats:       s.agent.Stats(),

agent/agent_endpoint_test.go

@@ -189,7 +189,7 @@ func TestAgent_Self(t *testing.T) {
 		t.Fatalf("incorrect port: %v", obj)
 	}
 
-	if val.Config["SerfPortLAN"].(int) != a.Config.SerfPortLAN {
+	if val.DebugConfig["SerfPortLAN"].(int) != a.Config.SerfPortLAN {
 		t.Fatalf("incorrect port: %v", obj)
 	}
 

api/agent_test.go

@@ -638,7 +638,7 @@ func TestAPI_AgentJoin(t *testing.T) {
 	}
 
 	// Join ourself
-	addr := info["Config"]["SerfAdvertiseAddrLAN"].(string)
+	addr := info["DebugConfig"]["SerfAdvertiseAddrLAN"].(string)
 	// strip off 'tcp://'
 	addr = addr[len("tcp://"):]
 	err = agent.Join(addr, false)

website/source/api/agent.html.md

@@ -85,7 +85,10 @@ $ curl \
 ## Read Configuration
 
 This endpoint returns the configuration and member information of the local
-agent.
+agent. The `Config` element contains a subset of the configuration and its
+format will not change in a backwards incompatible way between releases.
+`DebugConfig` contains the full runtime configuration but its format is subject
+to change without notice or deprecation.
 
 | Method | Path                         | Produces                   |
 | ------ | ---------------------------- | -------------------------- |
@@ -112,42 +115,15 @@ $ curl \
 ```json
 {
   "Config": {
-    "Bootstrap": true,
-    "Server": true,
     "Datacenter": "dc1",
-    "DataDir": "/tmp/consul",
-    "DNSRecursor": "",
-    "DNSRecursors": [],
-    "Domain": "consul.",
-    "LogLevel": "INFO",
-    "NodeID": "40e4a748-2192-161a-0510-9bf59fe950b5",
     "NodeName": "foobar",
-    "ClientAddr": "127.0.0.1",
-    "BindAddr": "0.0.0.0",
-    "AdvertiseAddr": "10.1.10.12",
-    "Ports": {
-      "DNS": 8600,
-      "HTTP": 8500,
-      "RPC": 8400,
-      "SerfLan": 8301,
-      "SerfWan": 8302,
-      "Server": 8300
+    "Server": true,
+    "Revision": "deadbeef",
+    "Version": "1.0.0"
   },
-    "LeaveOnTerm": false,
-    "SkipLeaveOnInt": false,
-    "StatsiteAddr": "",
-    "Protocol": 1,
-    "EnableDebug": false,
-    "VerifyIncoming": false,
-    "VerifyOutgoing": false,
-    "CAFile": "",
-    "CertFile": "",
-    "KeyFile": "",
-    "StartJoin": [],
-    "UiDir": "",
-    "PidFile": "",
-    "EnableSyslog": false,
-    "RejoinAfterLeave": false
+  "DebugConfig": {
+    ... full runtime configuration ...
+    ... format subject to change ...
   },
   "Coord": {
     "Adjustment": 0,