* jobspec: breakup parse.go into smaller files
* add sidecar_task parsing to jobspec and api
* jobspec: combine service parsing logic for task and group service stanzas
* api: use slice of ConsulUpstream values instead of pointers
This seems to be the minimum viable patch for fixing a deadlock between
establishConnection and SetConfig.
SetConfig calls tomb.Kill+tomb.Wait while holding v.lock.
establishConnection needs to acquire v.lock to exit but SetConfig is
holding v.lock until tomb.Wait exits. tomb.Wait can't exit until
establishConnect does!
```
SetConfig -> tomb.Wait
^ |
| v
v.lock <- establishConnection
```
Also includes unit tests for binpacker and preemption.
The tests verify that network resources specified at the
task group level are properly accounted for
This ensures that server-to-server streaming RPC calls use the tls
wrapped connections.
Prior to this, `streamingRpcImpl` function uses tls for setting header
and invoking the rpc method, but returns unwrapped tls connection.
Thus, streaming writes fail with tls errors.
This tls streaming bug existed since 0.8.0[1], but PR #5654[2]
exacerbated it in 0.9.2. Prior to PR #5654, nomad client used to
shuffle servers at every heartbeat -- `servers.Manager.setServers`[3]
always shuffled servers and was called by heartbeat code[4]. Shuffling
servers meant that a nomad client would heartbeat and establish a
connection against all nomad servers eventually. When handling
streaming RPC calls, nomad servers used these local connection to
communicate directly to the client. The server-to-server forwarding
logic was left mostly unexercised.
PR #5654 means that a nomad client may connect to a single server only
and caused the server-to-server forward streaming RPC code to get
exercised more and unearthed the problem.
[1] https://github.com/hashicorp/nomad/blob/v0.8.0/nomad/rpc.go#L501-L515
[2] https://github.com/hashicorp/nomad/pull/5654
[3] https://github.com/hashicorp/nomad/blob/v0.9.1/client/servers/manager.go#L198-L216
[4] https://github.com/hashicorp/nomad/blob/v0.9.1/client/client.go#L1603
