From 2b797a556a90d56bf3eec525dde8515aadfa69c0 Mon Sep 17 00:00:00 2001
From: Reed Allman <reed@rdallman.com>
Date: Fri, 14 Sep 2018 16:54:18 +0100
Subject: [PATCH] update docs with pro tips for fdk http stream people (#1211)

* update docs with pro tips for fdk http stream people

* fix bug where container could die before uds wait

we used to hang out for an hour. oopsie, thanks Owen
---
 api/agent/agent.go           | 27 ++++++++++++++-------------
 docs/developers/fn-format.md |  2 +-
 2 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/api/agent/agent.go b/api/agent/agent.go
index c599ff19b..be0a95c28 100644
--- a/api/agent/agent.go
+++ b/api/agent/agent.go
@@ -925,19 +925,6 @@ func (a *agent) runHot(ctx context.Context, call *call, tok ResourceToken, state
 		return
 	}
 
-	// now we wait for the socket to be created before handing out any slots
-	select {
-	case err := <-udsAwait: // XXX(reed): need to leave a note about pairing ctx here?
-		// sends a nil error if all is good, we can proceed...
-		if err != nil {
-			call.slots.queueSlot(&hotSlot{done: make(chan struct{}), fatalErr: err})
-			return
-		}
-	case <-ctx.Done():
-		call.slots.queueSlot(&hotSlot{done: make(chan struct{}), fatalErr: ctx.Err()})
-		return
-	}
-
 	// container is running
 	state.UpdateState(ctx, ContainerStateIdle, call.slots)
 
@@ -949,6 +936,20 @@ func (a *agent) runHot(ctx context.Context, call *call, tok ResourceToken, state
 	go func() {
 		defer shutdownContainer() // also close if we get an agent shutdown / idle timeout
 
+		// now we wait for the socket to be created before handing out any slots, need this
+		// here in case the container dies before making the sock we need to bail
+		select {
+		case err := <-udsAwait: // XXX(reed): need to leave a note about pairing ctx here?
+			// sends a nil error if all is good, we can proceed...
+			if err != nil {
+				call.slots.queueSlot(&hotSlot{done: make(chan struct{}), fatalErr: err})
+				return
+			}
+		case <-ctx.Done():
+			call.slots.queueSlot(&hotSlot{done: make(chan struct{}), fatalErr: ctx.Err()})
+			return
+		}
+
 		for {
 			select { // make sure everything is up before trying to send slot
 			case <-ctx.Done(): // container shutdown
diff --git a/docs/developers/fn-format.md b/docs/developers/fn-format.md
index 666f32e1c..ac81441f3 100644
--- a/docs/developers/fn-format.md
+++ b/docs/developers/fn-format.md
@@ -32,7 +32,7 @@ If `FN_FORMAT` is `http-stream`, then absence of `FN_LISTENER` or "unix:" prefix
 
 Before exiting, FDKs __SHOULD__ remove the UDS file (from `FN_LISTENER` path).
 
-FDKs upon creation of UDS file on disk with bind system call __SHOULD__ be ready to receive and handle traffic. Upon bind call, the UDS file __MUST__ be writable by fn-agent.
+FDKs upon creation of UDS file on disk with bind system call __SHOULD__ be ready to receive and handle traffic. Upon bind call, the UDS file __MUST__ be writable by fn-agent. In order to create a properly permissioned UDS file, FDKs __MUST__ create a file with [at least] permissions of `0666`, if the language provides support for creating this file with the right permissions this may be easily achieved; users may alternatively bind to a file that is not `FN_LISTENER`, modify its permissions to the required setting, and then symlink that file to `FN_LISTENER` (see fdk-go for an example).
 
 Path in `FN_LISTENER` (after "unix:" prefix) cannot be larger than 107 bytes.