Development Update — April 3

Skywire: SKYDEPLOY Override

New environment variable (#2276) — SKYDEPLOY=/path/to/config.json overrides the embedded services-config.json deployment configuration. This supports:

• Private networks — point Skywire at a custom deployment without rebuilding
• Corporate deployments — run a private Skywire network with your own TPD, DMSG, Address Resolver, etc.
• Testing — quickly switch between test and production deployments

The embedded config is still used as the default, so nothing changes for users on the public network. But operators running private deployments no longer need to patch and rebuild Skywire to change the discovery URLs.

Skywire: CI Workflow Restructure

Separate update-commit workflow (#2275) — the commit-update automation was moved to its own workflow triggered by workflow_run (fires when the Test workflow succeeds), rather than running on push to develop. The push-to-develop trigger was removed from test.yml so there are no duplicate test runs. update-commit fetches the latest develop SHA only after PR tests pass.

DMSG retry improvements — transport retries increased from 3 to 5 with a 5-second base delay. DMSG self-transport warmup retries also increased to 5. These tune the retry logic for the flaky cases that the more aggressive CI had been exposing.

DMSG transport tests — fixed to check the visor’s DMSG state directly rather than relying on discovery lookups, which were race-prone in the test environment.

Dependency bumps — lodash from 4.17.23 to 4.18.1.

DMSG: Deployment Config and pprof Over DMSG

Unified deployment config (#365) — dmsg now reads its endpoints from ServicesJSON (the shared services-config.json) using _dmsg suffixed field names, instead of a separate dmsghttp-config.json. This eliminates the ping-pong between two config files and lets both HTTP and DMSG deployments use the same source of truth.

pprof over DMSG (#366) — ServeDebug(), DebugMux(), and WhitelistMiddleware() were added to pkg/dmsghttp/debug.go as reusable helpers. Access is controlled by survey_whitelist PKs. Wired into dmsg-discovery and dmsg-server on port 81.

This is a significant operational capability: you can now profile a DMSG server remotely over DMSG itself, without needing SSH access or exposing pprof on a public HTTP port. The whitelist ensures only authorized operators can access profiling data.

Direct client retry fix (#368) — when the direct client (used by DMSG services without discovery) failed to connect to a server, it backed off and then retried the same list from the start, potentially re-picking the same failing server immediately. Fixed:

• InitConfig now skips Prod/Test unmarshal when nil (supports single-deployment SKYDEPLOY configs)
• DialTimeout (10s) added to prevent blocking on unresponsive servers
• net.DialTimeout used instead of net.Dial in client session establishment
• serveWait backoff moved to after all servers have been tried, not after each individual failure

DMSG: smux Ping Timeout Fix and Config Tuning

smux ping timeout fix (#369) — the server-side ping echo wrote the 2-byte response but never closed the smux stream. Without an explicit close, smux buffered the response and the client’s read timed out waiting for data that never arrived. Fixed by closing the stream after the echo to flush the write buffer.

Defensive nil check in Stream.Close().

Yamux and smux config tuning — yamux: AcceptBacklog increased to 512, StreamOpenTimeout reduced to 20s, StreamCloseTimeout reduced to 30s, stderr logging suppressed via io.Discard. Smux: upgraded to protocol v2 (adds flow control), MaxReceiveBuffer reduced to 1MB per session (from 4MB).

The smux v2 upgrade is significant — flow control means senders can’t overwhelm slow receivers, which was an observed problem in production where a slow client could cause backpressure all the way through the DMSG server.