CLI tool for updating Route53 DNS for an ASG.

1 files changed, 68 insertions, 0 deletions

diff --git a/src/bin/aws-autoscaling-dns/main.rs b/src/bin/aws-autoscaling-dns/main.rs
new file mode 100644
index 0000000..739f0c8
--- /dev/null
+++ b/src/bin/aws-autoscaling-dns/main.rs
@@ -0,0 +1,68 @@
+use std::fmt::Debug;
+
+use clap::Parser;
+use trust_dns_proto::rr::Name;
+
+use aws_autoscaling_dns::apply::ApplyMode;
+use aws_autoscaling_dns::aws_context::AwsContext;
+use aws_autoscaling_dns::converge::named_asg_changes;
+use aws_autoscaling_dns::result::Result;
+
+/// Synchronize a DNS entry with an autoscaling group's running instances.
+///
+/// The given DNS name's A and AAAA records in Route53 will be rewritten to exactly
+/// match the list of pending and in-service EC2 instances in the specified
+/// autoscaling group. Records of other types (including CNAMEs) will not be
+/// modified, so this can be used alongside DNS ACME verification, SPF, and other
+/// DNS applications.
+#[derive(Parser, Debug)]
+struct Args {
+    /// The name of the autoscaling group to synchronize.
+    #[arg(long)]
+    autoscaling_group: String,
+
+    /// The DNS domain name to synchronize. The most specific Route53 zone that
+    /// contains this name will be modified.
+    #[arg(long)]
+    dns_name: Name,
+
+    /// The TTL (in seconds) for newly-created records.
+    #[arg(long, default_value_t = 300)]
+    dns_ttl: i64,
+
+    /// Print the affected zone ID and pending changes, without applying them (default).
+    #[arg(long, conflicts_with = "apply")]
+    dry_run: bool,
+
+    /// Apply the changes to Route53.
+    #[arg(long)]
+    apply: bool,
+}
+
+#[tokio::main]
+async fn main() -> Result<()> {
+    let args = Args::parse();
+    let name = args.autoscaling_group;
+
+    let aws_context = AwsContext::from_env().await;
+
+    let apply_mode = if args.dry_run {
+        ApplyMode::DryRun
+    } else if args.apply {
+        ApplyMode::Apply
+    } else {
+        ApplyMode::DryRun
+    };
+
+    let changes = named_asg_changes(&aws_context, &name, &args.dns_name, args.dns_ttl).await?;
+    apply_mode
+        .apply(
+            &aws_context,
+            &changes.zone_id,
+            changes.remove,
+            changes.insert,
+        )
+        .await?;
+
+    Ok(())
+}