api: system metrics endpoint

internal/api/v1/system_info.go

@@ -0,0 +1,53 @@
+package v1
+
+import (
+	"net/http"
+
+	agentPkg "github.com/yusing/go-proxy/agent/pkg/agent"
+	config "github.com/yusing/go-proxy/internal/config/types"
+	"github.com/yusing/go-proxy/internal/gperr"
+	"github.com/yusing/go-proxy/internal/metrics/systeminfo"
+	"github.com/yusing/go-proxy/internal/net/gphttp"
+	"github.com/yusing/go-proxy/internal/net/gphttp/httpheaders"
+	"github.com/yusing/go-proxy/internal/net/gphttp/reverseproxy"
+)
+
+func SystemInfo(cfg config.ConfigInstance, w http.ResponseWriter, r *http.Request) {
+	query := r.URL.Query()
+	agentAddr := query.Get("agent_addr")
+	query.Del("agent_addr")
+	if agentAddr == "" {
+		systeminfo.Poller.ServeHTTP(w, r)
+		return
+	}
+
+	agent, ok := cfg.GetAgent(agentAddr)
+	if !ok {
+		gphttp.NotFound(w, "agent_addr")
+		return
+	}
+
+	isWS := httpheaders.IsWebsocket(r.Header)
+	if !isWS {
+		respData, status, err := agent.Forward(r, agentPkg.EndpointSystemInfo)
+		if err != nil {
+			gphttp.ServerError(w, r, gperr.Wrap(err, "failed to forward request to agent"))
+			return
+		}
+		if status != http.StatusOK {
+			http.Error(w, string(respData), status)
+			return
+		}
+		gphttp.WriteBody(w, respData)
+	} else {
+		rp := reverseproxy.NewReverseProxy("agent", agentPkg.AgentURL, agent.Transport())
+		header := r.Header.Clone()
+		r, err := http.NewRequestWithContext(r.Context(), r.Method, agentPkg.EndpointSystemInfo+"?"+query.Encode(), nil)
+		if err != nil {
+			gphttp.ServerError(w, r, gperr.Wrap(err, "failed to create request"))
+			return
+		}
+		r.Header = header
+		rp.ServeHTTP(w, r)
+	}
+}