Add some helpful configs for testing during development

cmd/promxy/Makefile

@@ -0,0 +1,9 @@
+test-robust:
+	go build -race -mod=vendor -tags netgo,builtinassets && ./promxy --log-level=debug --http.shutdown-delay=0s --config=demo_robust.conf --web.external-url=http://localhost:8082/promxy
+
+
+test-local:
+	go build -race -mod=vendor -tags netgo,builtinassets && ./promxy --http.shutdown-delay=0s --config=local_test.conf --web.external-url=http://localhost:8082/promxy --log-level=debug
+
+version:
+	go build -race -mod=vendor -tags netgo,builtinassets && ./promxy --version

cmd/promxy/demo_robust.conf

@@ -0,0 +1,31 @@
+##
+## Regular prometheus configuration
+##
+global:
+  evaluation_interval: 60s
+  external_labels:
+    source: promxy
+
+##
+### Promxy configuration
+##
+promxy:
+  server_groups:
+    - static_configs:
+        - targets:
+          - demo.robustperception.io:9090
+      http_client:
+        dial_timeout: 1s
+        tls_config:
+          insecure_skip_verify: true
+      labels:
+        replica: a
+    - static_configs:
+        - targets:
+          - demo.robustperception.io:9090
+      http_client:
+        dial_timeout: 1s
+        tls_config:
+          insecure_skip_verify: true
+      labels:
+        replica: b

cmd/promxy/local_test.conf

@@ -0,0 +1,12 @@
+promxy:
+  server_groups:
+    - static_configs:
+        - targets:
+          - localhost:9090
+      labels:
+        dc: 1
+    - static_configs:
+        - targets:
+          - localhost:9090
+      labels:
+        dc: 2