main: handle exhausted join failure

gcp-mig-startup.sh

@@ -0,0 +1,5 @@
+#!/bin/bash
+mkdir /opt/zgroup/ && cd /opt/zgroup/
+wget https://github.com/flowerinthenight/zgroup/releases/download/v0.3.1/zgroup-v0.3.1-x86_64-linux.tar.gz
+tar -xzvf zgroup-v0.3.1-x86_64-linux.tar.gz
+# ZGROUP_JOIN_PREFIX=0b9303ad-1beb-483f-abb5-bc58e0214531 INTERNAL_IP=$(curl -H "Metadata-Flavor: Google" http://metadata.google.internal/computeMetadata/v1/instance/network-interfaces/0/ip) ./zgroup group1 ${INTERNAL_IP}:8080 2>&1 | logger &

src/main.zig

@@ -107,7 +107,7 @@ pub fn main() !void {
         if (joined)
             std.time.sleep(std.time.ns_per_s * 1)
         else
-            std.time.sleep(bo.pause());
+            std.time.sleep(if (i >= 100) std.time.ns_per_s else bo.pause());
 
         if (i > 1 and i < 100 and !joined) {
             switch (hm.count()) {
@@ -136,7 +136,12 @@ pub fn main() !void {
                         join_addr[0..sep],
                         join_port,
                         &joined,
-                    ) catch |err| log.err("join failed: {any}", .{err});
+                    ) catch |err|
+                        log.err("joining thru {s}:{d} failed: {any}", .{
+                        join_addr[0..sep],
+                        join_port,
+                        err,
+                    });
                 },
                 4 => {
                     // Join address is provided. Skip callback.

src/scratch.zig

@@ -207,3 +207,7 @@ test "envmap" {
         dbg("no PATH\n", .{});
     }
 }
+
+// gcloud compute instance-templates create sample-template-custom --machine-type e2-micro --metadata=startup-script=''"$(cat gcp-mig-startup.sh)"''
+// gcloud compute instance-groups managed create example-rmig --template sample-template-custom --size 3 --region asia-northeast1
+// sudo journalctl -u google-startup-scripts.service