flow: rename buffer-length option to buffer-size

It is a better match. I was worried people would understand the size
as in bytes, but we also say a channel size.

core/root.go

@@ -137,7 +137,7 @@ func (c *Component) runWorker(workerID int) error {
 				continue
 			}
 
-			// Forward to Kafka
+			// Forward to Kafka (this could block
 			c.d.Kafka.Send(sampler, buf.Bytes())
 			c.metrics.flowsForwarded.WithLabelValues(sampler).Inc()
 

docs/configuration.md

@@ -75,7 +75,7 @@ configuration keys:
 - `listen` to specify the IP and UDP port to listen for new flows
 - `workers` to specify the number of workers to spawn to handle
   incoming flows
-- `bufferlength` to specify the number of flows to buffer when pushing
+- `buffer-size` to specify the number of flows to buffer when pushing
   them to the core component
 
 For example:

docs/design.md

@@ -216,6 +216,11 @@ In the future, we may:
 - Add more information to the landing page, including some basic statistics.
 - Automatically build dashboards for Grafana.[^grafana]
 - Builds dashboards with [D3.js][].[^d3js]
+- Buffer message to disks instead of blocking (when sending to Kafka)
+  or dropping (when querying the SNMP poller). At least, we should
+  have a solution to clearly signal when something is not scaling as
+  intended, otherwise, we just drop buffers at the beginning of the
+  pipeline.
 - Collect routes by integrating GoBGP. This is low priority if we
   consider information from Maxmind good enough for our use.
 

flow/config.go

@@ -6,15 +6,15 @@ type Configuration struct {
 	Listen string
 	// Workers define the number of workers to use for decoding.
 	Workers int
-	// BufferLength defines the length of the channel used to
+	// BufferSize defines the size of the channel used to
 	// communicate incoming flows. 0 can be used to disable
 	// buffering.
-	BufferLength uint
+	BufferSize uint
 }
 
 // DefaultConfiguration represents the default configuration for the flow component
 var DefaultConfiguration = Configuration{
 	Listen:     "localhost:2055",
 	Workers:    1,
-	BufferLength: 1000,
+	BufferSize: 1000,
 }

flow/root.go

@@ -55,7 +55,7 @@ func New(r *reporter.Reporter, configuration Configuration, dependencies Depende
 		r:             r,
 		d:             &dependencies,
 		config:        configuration,
-		incomingFlows: make(chan *FlowMessage, configuration.BufferLength),
+		incomingFlows: make(chan *FlowMessage, configuration.BufferSize),
 	}
 	c.d.Daemon.Track(&c.t, "flow")
 	c.initHTTP()