reuse loop checker

1 files changed, 23 insertions, 9 deletions

diff --git a/bin/taler-gv b/bin/taler-gv
index a63bfca..9e6693c 100755
--- a/bin/taler-gv
+++ b/bin/taler-gv
@@ -529,6 +529,27 @@ CURRENCY = "KUDOS"
 def prepare(postgres_db_name):
     """Generate configuration, run-time blobs, instances, euFin accounts."""
 
+    def is_serving(check_url, tries=10):
+        for i in range(tries):
+            try:
+                print_nn(".")
+                # Raises if the service is not reachable.
+                response = requests.get(
+                    check_url,
+                    timeout=1
+                )
+                # The reverse proxy may return 500 if the
+                # end service is not ready, therefore this
+                # case should be tolerated.
+                response.raise_for_status()
+            except:
+                time.sleep(0.5)
+                if i == tries - 1:
+                    return False
+                continue
+            break
+        return True
+
     def fail(reason=None):
         if reason:
             print("ERROR:", reason)
@@ -1315,15 +1336,8 @@ def prepare(postgres_db_name):
     print(" OK")
     print_nn("Launching the exchange...")
     subprocess.run(["systemctl", "--user", "start", "taler-local-exchange-httpd.service"])
-    res = requests.get("https://exchange.demo.taler.net/")
-    res_count = 0
-    while res.status_code != 200:
-        if res_count == 10:
-            print("Exchange unreachable")
-            sys.exit(1)
-        res_count = res_count + 1
-        time.sleep(1)
-        res = requests.get("https://exchange.demo.taler.net/")
+    if not is_serving("https://exchange.demo.taler.net/"):
+        fail(f"Exchange did not start correctly.")
     print(" OK")
     print_nn("exchange-offline: signing key material...")
     Command([