Addressing scope of tenant prefix

processor.go

@@ -170,10 +170,12 @@ func (p *processor) handle(ctx *fh.RequestCtx) {
 		return
 	}
 
+	tenantPrefix := p.cfg.Tenant.Prefix
+
 	if p.cfg.Tenant.PrefixPreferSource {
 		sourceTenantPrefix := string(ctx.Request.Header.Peek(p.cfg.Tenant.Header))
 		if sourceTenantPrefix != "" {
-			p.cfg.Tenant.Prefix = sourceTenantPrefix + "-"
+			tenantPrefix = sourceTenantPrefix + "-"
 		}
 	}
 
@@ -184,7 +186,7 @@ func (p *processor) handle(ctx *fh.RequestCtx) {
 		// If there's metadata - just accept the request and drop it
 		if len(wrReqIn.Metadata) > 0 {
 			if p.cfg.Metadata && p.cfg.Tenant.Default != "" {
-				r := p.send(clientIP, reqID, p.cfg.Tenant.Default, wrReqIn)
+				r := p.send(clientIP, reqID, tenantPrefix, p.cfg.Tenant.Default, wrReqIn)
 				if r.err != nil {
 					ctx.Error(err.Error(), fh.StatusInternalServerError)
 					p.Errorf("src=%s req_id=%s: unable to proxy metadata: %s", clientIP, reqID, r.err)
@@ -209,7 +211,7 @@ func (p *processor) handle(ctx *fh.RequestCtx) {
 
 	metricTenant := ""
 	var errs *me.Error
-	results := p.dispatch(clientIP, reqID, m)
+	results := p.dispatch(clientIP, reqID, tenantPrefix, m)
 
 	code, body := 0, []byte("Ok")
 
@@ -311,20 +313,20 @@ func (p *processor) marshal(wr *prompb.WriteRequest) (bufOut []byte, err error)
 	return snappy.Encode(nil, b), nil
 }
 
-func (p *processor) dispatch(clientIP net.Addr, reqID uuid.UUID, m map[string]*prompb.WriteRequest) (res []result) {
+func (p *processor) dispatch(clientIP net.Addr, reqID uuid.UUID, tenantPrefix string, m map[string]*prompb.WriteRequest) (res []result) {
 	var wg sync.WaitGroup
 	res = make([]result, len(m))
 
 	i := 0
 	for tenant, wrReq := range m {
 		wg.Add(1)
 
-		go func(idx int, tenant string, wrReq *prompb.WriteRequest) {
+		go func(idx int, tenantPrefix string, tenant string, wrReq *prompb.WriteRequest) {
 			defer wg.Done()
 
-			r := p.send(clientIP, reqID, tenant, wrReq)
+			r := p.send(clientIP, reqID, tenantPrefix, tenant, wrReq)
 			res[idx] = r
-		}(i, tenant, wrReq)
+		}(i, tenantPrefix, tenant, wrReq)
 
 		i++
 	}
@@ -367,7 +369,7 @@ func (p *processor) processTimeseries(ts *prompb.TimeSeries) (tenant string, err
 	return
 }
 
-func (p *processor) send(clientIP net.Addr, reqID uuid.UUID, tenant string, wr *prompb.WriteRequest) (r result) {
+func (p *processor) send(clientIP net.Addr, reqID uuid.UUID, tenantPrefix string, tenant string, wr *prompb.WriteRequest) (r result) {
 	start := time.Now()
 	r.tenant = tenant
 
@@ -385,6 +387,10 @@ func (p *processor) send(clientIP net.Addr, reqID uuid.UUID, tenant string, wr *
 		return
 	}
 
+	if tenantPrefix != "" {
+		tenant = tenantPrefix + tenant
+	}
+
 	p.fillRequestHeaders(clientIP, reqID, tenant, req)
 
 	if p.auth.egressHeader != nil {
@@ -415,9 +421,6 @@ func (p *processor) fillRequestHeaders(
 	req.Header.Set("X-Prometheus-Remote-Write-Version", "0.1.0")
 	req.Header.Set("X-Cortex-Tenant-Client", clientIP.String())
 	req.Header.Set("X-Cortex-Tenant-ReqID", reqID.String())
-	if p.cfg.Tenant.Prefix != "" {
-		tenant = p.cfg.Tenant.Prefix + tenant
-	}
 	req.Header.Set(p.cfg.Tenant.Header, tenant)
 }
 

processor_test.go

@@ -232,20 +232,6 @@ func Test_request_headers(t *testing.T) {
 	assert.Equal(t, "my-tenant", string(req.Header.Peek("X-Scope-OrgID")))
 }
 
-func Test_request_headers_with_prefix(t *testing.T) {
-	cfg, err := getConfig(testConfigWithValues)
-	assert.Nil(t, err)
-
-	p := newProcessor(*cfg)
-
-	req := fh.AcquireRequest()
-	clientIP, _ := net.ResolveIPAddr("ip", "1.1.1.1")
-	reqID, _ := uuid.NewRandom()
-	p.fillRequestHeaders(clientIP, reqID, "my-tenant", req)
-
-	assert.Equal(t, "foobar-my-tenant", string(req.Header.Peek("X-Scope-OrgID")))
-}
-
 func Test_handle(t *testing.T) {
 	cfg, err := getConfig(testConfig)
 	assert.Nil(t, err)