How it works

When an entry is created, a series of slots are created as well. These slots have different responsibilities, some for tracing; some for collecting and calculating run-time information, some for controlling flow;some for authorization, etc. Users can customize his own logic by adding slots based on following 3 fundamental slots.

NodeSelectorSlot: trace nodes and form a calling tree in the memory

 ContextUtil.enter("entrance1", "appA", null, EntryType.IN);
 Entry nodeA = SphU.entry("nodeA");
 if (nodeA != null) {
    nodeA.exit();
 }
 ContextUtil.exit();

Above code will generate following structure in memory:

 	     machine-root
                 /     
                /
         EntranceNode1
              /
             /   
      DefaultNode(nodeA)

Each DefaultNode is identified by both the resource id and enter name. In other words, one resource id, may have multiple default nodes distinguished by enter name declared in ContextUtil.enter(name)

  ContextUtil.enter("entrance1", "appA", null, EntryType.IN);
  Entry nodeA = SphU.entry("nodeA");
  if (nodeA != null) {
    nodeA.exit();
  }
  ContextUtil.exit();
  ContextUtil.enter("entrance2", "appA", null, EntryType.IN);
  nodeA = SphU.entry("nodeA");
  if (nodeA != null) {
    nodeA.exit();
  }
  ContextUtil.exit();

Above code will generate the following structure in memory:

                   machine-root
                   /         \
                  /           \
          EntranceNode1   EntranceNode2
                /               \
               /                 \
       DefaultNode(nodeA)   DefaultNode(nodeA)

The calling trace can be displayed by calling curl http://localhost:8719/tree?type=root.

EntranceNode: machine-root(t:0 pq:1 bq:0 tq:1 rt:0 prq:1 1mp:0 1mb:0 1mt:0)
-EntranceNode1: Entrance1(t:0 pq:1 bq:0 tq:1 rt:0 prq:1 1mp:0 1mb:0 1mt:0)
--nodeA(t:0 pq:1 bq:0 tq:1 rt:0 prq:1 1mp:0 1mb:0 1mt:0)
-EntranceNode2: Entrance1(t:0 pq:1 bq:0 tq:1 rt:0 prq:1 1mp:0 1mb:0 1mt:0)
--nodeA(t:0 pq:1 bq:0 tq:1 rt:0 prq:1 1mp:0 1mb:0 1mt:0)

t:threadNum  pq:passQps  bq:blockedQps  tq:totalQps  rt:averageRt  prq: passRequestQps 1mp:1m-passed 1mb:1m-blocked 1mt:1m-total

ClusterNodeBuilderSlot - build cluster node named by resource

This slot maintains resource running statistics (response time, qps, thread, count, exception), and a list of origin callers statistics. The origin caller's name is marked by {@code Context.enter(entryname, origin)}.

The information can be displayed by calling url: curl http://localhost:8719/origin?id=xxxx

id: nodeA
idx origin  threadNum passedQps blockedQps totalQps aRt   1m-passed 1m-blocked 1m-total 
1   caller1 0         0         0          0        0     0         0          0        
2   caller2 0         0         0          0        0     0         0          0        

StatisticSlot - this slots collects runtime statistics

• cluster node: total statistics of a cluster node of the resource id  
• origin node: statistics of a cluster node from different callers  
• default node: the entry of the node, marked by context entry name and resource id
• the total sum statistics of incoming entrances