Added: helix/site-content/0.9.5-docs/tutorial_rest_service.html URL: http://svn.apache.org/viewvc/helix/site-content/0.9.5-docs/tutorial_rest_service.html?rev=1877599&view=auto ============================================================================== --- helix/site-content/0.9.5-docs/tutorial_rest_service.html (added) +++ helix/site-content/0.9.5-docs/tutorial_rest_service.html Mon May 11 18:32:11 2020 @@ -0,0 +1,1231 @@ + + + + + + + + Apache Helix - Tutorial - REST Service 2.0 + + + + + + + + + + + + + + + + + + + + + + + + + +
+ + +
+ +
+ +
+
+ +
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+
+
+ +

+
+ +

New Helix REST service supported features:

+
    +
  • Expose all admin operations via restful API. +
      +
    • All of Helix admin operations, include these defined in HelixAdmin.java and ConfigAccessor.java, etc, are exposed via rest API.
    • +
  • +
  • Support all task framework API via restful.Current task framework operations are supported from rest API too.
  • +
  • More standard Restful API +
      +
    • Use the standard HTTP methods if possible, GET, POST, PUT, DELETE, instead of customized command as it today.
    • +
    • Customized command will be used if there is no corresponding HTTP methods, for example, rebalance a resource, disable an instance, etc.
    • +
  • +
  • Make Helix restful service an separately deployable service.
  • +
  • Enable Access/Audit log for all write access.
  • +
+
+

Installation

+

The command line tool comes with helix-core package:

+

Get the command line tool:

+
+
git clone https://git-wip-us.apache.org/repos/asf/helix.git
+cd helix
+git checkout tags/helix-0.9.5
+./build
+cd helix-rest/target/helix-rest-pkg/bin
+chmod +x *.sh
+
+
+

Get help:

+
+
./run-rest-admin.sh --help
+
+
+

Start the REST server

+
+
./run-rest-admin.sh --port 1234 --zkSvr localhost:2121
+
+
+
+
+

Helix REST 2.0 Endpoint

+

Helix REST 2.0 endpoint will start with /admin/v2 prefix, and the rest will mostly follow the current URL convention. This allows us to support v2.0 endpoint at the same time with the current Helix web interface. Some sample v2.0 endpoints would look like the following:

+
+
curl -X GET http://localhost:12345/admin/v2/clusters
+curl -X POST http://localhost:12345/admin/v2/clusters/myCluster
+curl -X POST http://localhost:12345/admin/v2/clusters/myCluster?command=activate&supercluster=controler_cluster
+curl http://localhost:12345/admin/v2/clusters/myCluster/resources/myResource/IdealState
+
+
+
+
+

REST Endpoints and Supported Operations

+
+

Operations on Helix Cluster

+
    +
  • “/clusters”

    + +
    +
    $curl http://localhost:1234/admin/v2/clusters
    +{
    +  "clusters" : [ "cluster1", "cluster2", "cluster3"]
    +}
    +
    +
  • +
+
    +
  • “/clusters/{clusterName}”

    + +
    +
    ```
    +$curl http://localhost:1234/admin/v2/clusters/myCluster
    +{
    +  "id" : "myCluster",
    +  "paused" : true,
    +  "disabled" : true,
    +  "controller" : "helix.apache.org:1234",
    +  "instances" : [ "aaa.helix.apache.org:1234", "bbb.helix.apache.org:1234" ],
    +  "liveInstances" : ["aaa.helix.apache.org:1234"],
    +  "resources" : [ "resource1", "resource2", "resource3" ],
    +  "stateModelDefs" : [ "MasterSlave", "LeaderStandby", "OnlineOffline" ]
    +}
    +```
    +
    +
    +
  • +
  • “/clusters/{clusterName}/configs”

    +
      +
    • Represents cluster level configs for cluster with {clusterName}
    • +
    • GET: get all configs.
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/configs
    +{
    +  "id" : "myCluster",
    +  "simpleFields" : {
    +    "PERSIST_BEST_POSSIBLE_ASSIGNMENT" : "true"
    +  },
    +  "listFields" : {
    +  },
    +  "mapFields" : {
    +  }
    +}
    +
    +
    +
      +
    • POST: update or delete one/some config entries.
      update – Update the entries included in the input.
    • +
    +
    +
    $curl -X POST -H "Content-Type: application/json" http://localhost:1234/admin/v2/clusters/myCluster/configs?command=update -d '
    +{
    + "id" : "myCluster",
    +  "simpleFields" : {
    +    "PERSIST_BEST_POSSIBLE_ASSIGNMENT" : "true"
    +  },
    +  "listFields" : {
    +    "disabledPartition" : ["p1", "p2", "p3"]
    +  },
    +  "mapFields" : {
    +  }
    +}'
    +
    +

    delete – Remove the entries included in the input from current config.

    +
    +
    $curl -X POST -H "Content-Type: application/json" http://localhost:1234/admin/v2/clusters/myCluster/configs?command=update -d '
    +{
    +  "id" : "myCluster",
    +  "simpleFields" : {
    +  },
    +  "listFields" : {
    +    "disabledPartition" : ["p1", "p3"]
    +  },
    +  "mapFields" : {
    +  }
    +}'
    +
    +
  • +
  • “/clusters/{clusterName}/controller”

    +
      +
    • Represents the controller for cluster {clusterName}.
    • +
    • GET – return controller information
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/controller
    +{
    +  "id" : "myCluster",
    +  "controller" : "test.helix.apache.org:1234",
    +  "HELIX_VERSION":"0.9.5",
    +  "LIVE_INSTANCE":"16261@test.helix.apache.org:1234",
    +  "SESSION_ID":"35ab496aba54c99"
    +}
    +
    +
  • +
  • “/clusters/{clusterName}/controller/errors”

    +
      +
    • Represents error information for the controller of cluster {clusterName}. This is new endpoint in v2.0.
    • +
    • GET – get all error information.
    • +
    • DELETE – clean up all error logs.
    • +
  • +
+
    +
  • “/clusters/{clusterName}/controller/history”

    +
      +
    • Represents the change history of leader controller of cluster {clusterName}. This is new endpoint in v2.0.
    • +
    • GET – get the leader controller history.
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/controller/history
    +{
    +  "id" : "myCluster",
    +  "history" [
    +      "{DATE=2017-03-21-16:57:14, CONTROLLER=test1.helix.apache.org:1234, TIME=1490115434248}",
    +      "{DATE=2017-03-27-22:35:16, CONTROLLER=test3.helix.apache.org:1234, TIME=1490654116484}",
    +      "{DATE=2017-03-27-22:35:24, CONTROLLER=test2.helix.apache.org:1234, TIME=1490654124926}"
    +  ]
    +}
    +
    +
  • +
  • /clusters/{clusterName}/controller/messages"

    +
      +
    • Represents all uncompleted messages currently received by the controller of cluster {clusterName}. This is new endpoint in v2.0.
    • +
    • GET – list all uncompleted messages received by the controller.
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/controller/messages
    +{
    +  "id" : "myCluster",
    +  "count" : 5,
    +  "messages" [
    +      "0b8df4f2-776c-4325-96e7-8fad07bd9048",
    +      "13a8c0af-b77e-4f5c-81a9-24fedb62cf58"
    +  ]
    +}
    +
    +
  • +
  • “/clusters/{clusterName}/controller/messages/{messageId}”

    +
      +
    • Represents the messages currently received by the controller of cluster {clusterName} with id {messageId}. This is new endpoint in v2.0.
    • +
    • GET - get the message with {messageId} received by the controller.
    • +
    • DELETE - delete the message with {messageId}
    • +
  • +
+
    +
  • “/clusters/{clusterName}/statemodeldefs/”

    +
      +
    • Represents all the state model definitions defined in cluster {clusterName}. This is new endpoint in v2.0.
    • +
    • GET - get all the state model definition in the cluster.
    • +
    +
    +
    $curl -X POST -H "Content-Type: application/json" http://localhost:1234/admin/v2/clusters/myCluster/statemodeldefs
    +{
    +  "id" : "myCluster",
    +  "stateModelDefs" : [ "MasterSlave", "LeaderStandby", "OnlineOffline" ]
    +}
    +
    +
  • +
  • “/clusters/{clusterName}/statemodeldefs/{statemodeldef}”

    +
      +
    • Represents the state model definition {statemodeldef} defined in cluster {clusterName}. This is new endpoint in v2.0.
    • +
    • GET - get the state model definition
    • +
    +
    +
    $curl -X POST -H "Content-Type: application/json" http://localhost:1234/admin/v2/clusters/myCluster/statemodeldefs/MasterSlave
    +{
    +  "id" : "MasterSlave",
    +  "simpleFields" : {
    +    "INITIAL_STATE" : "OFFLINE"
    +  },
    +  "mapFields" : {
    +    "DROPPED.meta" : {
    +      "count" : "-1"
    +    },
    +    "ERROR.meta" : {
    +      "count" : "-1"
    +    },
    +    "ERROR.next" : {
    +      "DROPPED" : "DROPPED",
    +      "OFFLINE" : "OFFLINE"
    +    },
    +    "MASTER.meta" : {
    +      "count" : "1"
    +    },
    +    "MASTER.next" : {
    +      "SLAVE" : "SLAVE",
    +      "DROPPED" : "SLAVE",
    +      "OFFLINE" : "SLAVE"
    +    },
    +    "OFFLINE.meta" : {
    +      "count" : "-1"
    +    },
    +    "OFFLINE.next" : {
    +      "SLAVE" : "SLAVE",
    +      "MASTER" : "SLAVE",
    +      "DROPPED" : "DROPPED"
    +    },
    +    "SLAVE.meta" : {
    +      "count" : "R"
    +    },
    +    "SLAVE.next" : {
    +      "MASTER" : "MASTER",
    +      "DROPPED" : "OFFLINE",
    +      "OFFLINE" : "OFFLINE"
    +    }
    +  },
    +  "listFields" : {
    +    "STATE_PRIORITY_LIST" : [ "MASTER", "SLAVE", "OFFLINE", "DROPPED", "ERROR" ],
    +    "STATE_TRANSITION_PRIORITYLIST" : [ "MASTER-SLAVE", "SLAVE-MASTER", "OFFLINE-SLAVE", "SLAVE-OFFLINE", "OFFLINE-DROPPED" ]
    +  }
    +}
    +
    +
    +
      +
    • POST - add a new state model definition with {statemodeldef}
    • +
    • DELETE - delete the state model definition
    • +
  • +
+
+
+

Helix “Resource” and its sub-resources

+
    +
  • “/clusters/{clusterName}/resources”

    +
      +
    • Represents all resources in a cluster.
    • +
    • GET - list all resources with their IdealStates and ExternViews.
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/resources
    +{
    +  "id" : "myCluster",
    +  "idealstates" : [ "idealstate1", "idealstate2", "idealstate3" ],
    +  "externalviews" : [ "idealstate1", "idealstate3" ]
    +}
    +
    +
  • +
  • “/clusters/{clusterName}/resources/{resourceName}”

    +
      +
    • Represents a resource in cluster {clusterName} with name {resourceName}
    • +
    • GET - get resource info
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/resources/resource1
    +{
    +  "id" : "resource1",
    +  "resourceConfig" : {},
    +  "idealState" : {},
    +  "externalView" : {}
    +}
    +
    +
    +
      +
    • PUT - add a resource with {resourceName}
    • +
    +
    +
    $curl -X PUT -H "Content-Type: application/json" http://localhost:1234/admin/v2/clusters/myCluster/resources/myResource -d '
    +{
    +  "id":"myResource",
    +  "simpleFields":{
    +    "STATE_MODEL_FACTORY_NAME":"DEFAULT"
    +    ,"EXTERNAL_VIEW_DISABLED":"true"
    +    ,"NUM_PARTITIONS":"1"
    +    ,"REBALANCE_MODE":"TASK"
    +    ,"REPLICAS":"1"
    +    ,"IDEAL_STATE_MODE":"AUTO"
    +    ,"STATE_MODEL_DEF_REF":"Task"
    +    ,"REBALANCER_CLASS_NAME":"org.apache.helix.task.WorkflowRebalancer"
    +  }
    +}'
    +
    +
    +
  • +
  • “/clusters/{clusterName}/resources/{resourceName}/idealState”

    +
      +
    • Represents the ideal state of a resource with name {resourceName} in cluster {clusterName}. This is new endpoint in v2.0.
    • +
    • GET - get idealstate.
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/resources/myResource/idealState
    +{
    +  "id":"myResource"
    +  ,"simpleFields":{
    +    "IDEAL_STATE_MODE":"AUTO"
    +    ,"NUM_PARTITIONS":"2"
    +    ,"REBALANCE_MODE":"SEMI_AUTO"
    +    ,"REPLICAS":"2"
    +    ,"STATE_MODEL_DEF_REF":"MasterSlave"
    +  }
    +  ,"listFields":{
    +    "myResource_0":["host1", "host2"]
    +    ,"myResource_1":["host2", "host1"]
    +  }
    +  ,"mapFields":{
    +    "myResource_0":{
    +      "host1":"MASTER"
    +      ,"host2":"SLAVE"
    +    }
    +    ,"myResource_1":{
    +      "host1":"SLAVE"
    +      ,"host2":"MASTER"
    +    }
    +  }
    +}
    +
    +
  • +
  • “/clusters/{clusterName}/resources/{resourceName}/externalView”

    +
      +
    • Represents the external view of a resource with name {resourceName} in cluster {clusterName}
    • +
    • GET - get the externview
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/resources/myResource/externalView
    +{
    +  "id":"myResource"
    +  ,"simpleFields":{
    +    "IDEAL_STATE_MODE":"AUTO"
    +    ,"NUM_PARTITIONS":"2"
    +    ,"REBALANCE_MODE":"SEMI_AUTO"
    +    ,"REPLICAS":"2"
    +    ,"STATE_MODEL_DEF_REF":"MasterSlave"
    +  }
    +  ,"listFields":{
    +    "myResource_0":["host1", "host2"]
    +    ,"myResource_1":["host2", "host1"]
    +  }
    +  ,"mapFields":{
    +    "myResource_0":{
    +      "host1":"MASTER"
    +      ,"host2":"OFFLINE"
    +    }
    +    ,"myResource_1":{
    +      "host1":"SLAVE"
    +      ,"host2":"MASTER"
    +    }
    +  }
    +}
    +
    +
  • +
  • “/clusters/{clusterName}/resources/{resourceName}/configs”

    +
      +
    • Represents resource level of configs for resource with name {resourceName} in cluster {clusterName}. This is new endpoint in v2.0.
    • +
    • GET - get resource configs.
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/resources/myResource/configs
    +{
    +  "id":"myDB"
    +  "UserDefinedProperty" : "property"
    +}
    +
    +
  • +
+
+
+

Helix Instance and its sub-resources

+
    +
  • “/clusters/{clusterName}/instances”

    +
      +
    • Represents all instances in a cluster {clusterName}
    • +
    • GET - list all instances in this cluster.
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/instances
    +{
    +  "id" : "myCluster",
    +  "instances" : [ "host1", "host2", "host3", "host4"],
    +  "online" : ["host1", "host4"],
    +  "disabled" : ["host2"]
    +}
    +
    +
    +
      +
    • POST - enable/disable instances.
    • +
    +
    +
    $curl -X POST -H "Content-Type: application/json" http://localhost:1234/admin/v2/clusters/myCluster/instances/command=enable -d
    +{
    +  "instances" : [ "host1", "host3" ]
    +}
    +$curl -X POST -H "Content-Type: application/json" http://localhost:1234/admin/v2/clusters/myCluster/instances/command=disable -d
    +{
    +  "instances" : [ "host2", "host4" ]
    +}
    +
    +
  • +
  • “/clusters/{clusterName}/instances/{instanceName}”

    +
      +
    • Represents a instance in cluster {clusterName} with name {instanceName}
    • +
    • GET - get instance information.
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/instances/host_1234
    +{
    +  "id" : "host_1234",
    +  "configs" : {
    +    "HELIX_ENABLED" : "true",
    +    "HELIX_HOST" : "host",
    +    "HELIX_PORT" : "1234",
    +    "HELIX_DISABLED_PARTITION" : [ ]
    +  }
    +  "liveInstance" : {
    +    "HELIX_VERSION":"0.6.6.3",
    +    "LIVE_INSTANCE":"4526@host",
    +    "SESSION_ID":"359619c2d7efc14"
    +  }
    +}
    +
    +
    +
      +
    • PUT - add a new instance with {instanceName}
    • +
    +
    +
    $curl -X PUT -H "Content-Type: application/json" http://localhost:1234/admin/v2/clusters/myCluster/instances/host_1234 -d '
    +{
    +  "id" : "host_1234",
    +  "simpleFields" : {
    +    "HELIX_ENABLED" : "true",
    +    "HELIX_HOST" : "host",
    +    "HELIX_PORT" : "1234",
    +  }
    +}'
    +
    +

    There’s one important restriction for this operation: the {instanceName} should match exactly HELIX_HOST + “_” + HELIX_PORT. For example, if host is localhost, and port is 1234, the instance name should be localhost_1234. Otherwise, the response won’t contain any error but the configurations are not able to be filled in.

    + +
      +
    • addInstanceTag - add tags to this instance.
    • +
    +
    +
    $curl -X POST -H "Content-Type: application/json" http://localhost:1234/admin/v2/clusters/myCluster/instances/host_1234?command=addInstanceTag -d '
    +{
    +  "id" : "host_1234",
    +  "instanceTags" : [ "tag_1", "tag_2, "tag_3" ]
    +}'
    +
    +
    +
      +
    • removeInstanceTag - remove a tag from this instance.
    • +
    +
    +
    $curl -X POST -H "Content-Type: application/json" http://localhost:1234/admin/v2/clusters/myCluster/instances/host_1234?command=removeInstanceTag -d '
    +{
    +  "id" : "host_1234",
    +  "instanceTags" : [ "tag_1", "tag_2, "tag_3" ]
    +}'
    +
    +
  • +
  • “/clusters/{clusterName}/instances/{instanceName}/resources”

    +
      +
    • Represents all resources and their partitions locating on the instance in cluster {clusterName} with name {instanceName}. This is new endpoint in v2.0.
    • +
    • GET - return all resources that have partitions in the instance.
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/instances/host_1234/resources
    +{
    +  "id" : "host_1234",
    +  "resources" [ "myResource1", "myResource2", "myResource3"]
    +}
    +
    +
  • +
  • “/clusters/{clusterName}/instances/{instanceName}/resources/{resource}”

    +
      +
    • Represents all partitions of the {resource} locating on the instance in cluster {clusterName} with name {instanceName}. This is new endpoint in v2.0.
    • +
    • GET - return all partitions of the resource in the instance.
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/instances/localhost_1234/resources/myResource1
    +{
    +  "id":"myResource1"
    +  ,"simpleFields":{
    +    "STATE_MODEL_DEF":"MasterSlave"
    +    ,"STATE_MODEL_FACTORY_NAME":"DEFAULT"
    +    ,"BUCKET_SIZE":"0"
    +    ,"SESSION_ID":"359619c2d7f109b"
    +  }
    +  ,"listFields":{
    +  }
    +  ,"mapFields":{
    +    "myResource1_2":{
    +      "CURRENT_STATE":"SLAVE"
    +      ,"INFO":""
    +    }
    +    ,"myResource1_3":{
    +      "CURRENT_STATE":"MASTER"
    +      ,"INFO":""
    +    }
    +    ,"myResource1_0":{
    +      "CURRENT_STATE":"MASTER"
    +      ,"INFO":""
    +    }
    +    ,"myResource1_1":{
    +      "CURRENT_STATE":"SLAVE"
    +      ,"INFO":""
    +    }
    +  }
    +}
    +
    +
  • +
  • “/clusters/{clusterName}/instances/{instanceName}/configs”

    +
      +
    • Represents instance configs in cluster {clusterName} with name {instanceName}. This is new endpoint in v2.0.
    • +
    • GET - return configs for the instance.
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/instances/host_1234/configs 
    +{
    +  "id":"host_1234"
    +  "configs" : {
    +    "HELIX_ENABLED" : "true",
    +    "HELIX_HOST" : "host"
    +    "HELIX_PORT" : "1234",
    +    "HELIX_DISABLED_PARTITION" : [ ]
    +}
    +
    +
    +
      +
    • PUT - PLEASE NOTE THAT THIS PUT IS FULLY OVERRIDE THE INSTANCE CONFIG
    • +
    +
    +
    $curl -X PUT -H "Content-Type: application/json" http://localhost:1234/admin/v2/clusters/myCluster/instances/host_1234/configs
    +{
    +  "id":"host_1234"
    +  "configs" : {
    +    "HELIX_ENABLED" : "true",
    +    "HELIX_HOST" : "host"
    +    "HELIX_PORT" : "1234",
    +    "HELIX_DISABLED_PARTITION" : [ ]
    +}
    +
    +
  • +
  • “/clusters/{clusterName}/instances/{instanceName}/errors”

    +
      +
    • List all the mapping of sessionId to partitions of resources. This is new endpoint in v2.0.
    • +
    • GET - get mapping
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/instances/host_1234/errors
    +{
    +   "id":"host_1234"
    +   "errors":{
    +        "35sfgewngwese":{
    +            "resource1":["p1","p2","p5"],
    +            "resource2":["p2","p7"]
    +         }
    +    }
    +}
    +
    +
    +
      +
    • DELETE - clean up all error information from Helix.
    • +
  • +
  • “/clusters/{clusterName}/instances/{instanceName}/errors/{sessionId}/{resourceName}/{partitionName}”

    +
      +
    • Represents error information for the partition {partitionName} of the resource {resourceName} under session {sessionId} in instance with {instanceName} in cluster {clusterName}. This is new endpoint in v2.0.
    • +
    • GET - get all error information.
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/instances/host_1234/errors/35sfgewngwese/resource1/p1
    +{
    +  "id":"35sfgewngwese_resource1"
    +  ,"simpleFields":{
    +  }
    +  ,"listFields":{
    +  }
    +  ,"mapFields":{
    +    "HELIX_ERROR     20170521-070822.000561 STATE_TRANSITION b819a34d-41b5-4b42-b497-1577501eeecb":{
    +      "AdditionalInfo":"Exception while executing a state transition task ..."
    +      ,"MSG_ID":"4af79e51-5f83-4892-a271-cfadacb0906f"
    +      ,"Message state":"READ"
    +    }
    +  }
    +}
    +
    +
  • +
  • “/clusters/{clusterName}/instances/{instanceName}/history”

    +
      +
    • Represents instance session change history for the instance with {instanceName} in cluster {clusterName}. This is new endpoint in v2.0.
    • +
    • GET - get the instance change history.
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/instances/host_1234/history
    +{
    +  "id": "host_1234",
    +  "LAST_OFFLINE_TIME": "183948792",
    +  "HISTORY": [
    +    "{DATE=2017-03-02T19:25:18:915, SESSION=459014c82ef3f5b, TIME=1488482718915}",
    +    "{DATE=2017-03-10T22:24:53:246, SESSION=15982390e5d5c91, TIME=1489184693246}",
    +    "{DATE=2017-03-11T02:03:52:776, SESSION=15982390e5d5d85, TIME=1489197832776}",
    +    "{DATE=2017-03-13T18:15:00:778, SESSION=15982390e5d678d, TIME=1489428900778}",
    +    "{DATE=2017-03-21T02:47:57:281, SESSION=459014c82effa82, TIME=1490064477281}",
    +    "{DATE=2017-03-27T14:51:06:802, SESSION=459014c82f01a07, TIME=1490626266802}",
    +    "{DATE=2017-03-30T00:05:08:321, SESSION=5590151804e2c78, TIME=1490832308321}",
    +    "{DATE=2017-03-30T01:17:34:339, SESSION=2591d53b0421864, TIME=1490836654339}",
    +    "{DATE=2017-03-30T17:31:09:880, SESSION=2591d53b0421b2a, TIME=1490895069880}",
    +    "{DATE=2017-03-30T18:05:38:220, SESSION=359619c2d7f109b, TIME=1490.9.538220}"
    +  ]
    +}
    +
    +
  • +
  • “/clusters/{clusterName}/instances/{instanceName}/messages”

    +
      +
    • Represents all uncompleted messages currently received by the instance. This is new endpoint in v2.0.
    • +
    • GET - list all uncompleted messages received by the controller.
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/instances/host_1234/messages
    +{
    +  "id": "host_1234",
    +  "new_messages": ["0b8df4f2-776c-4325-96e7-8fad07bd9048", "13a8c0af-b77e-4f5c-81a9-24fedb62cf58"],
    +  "read_messages": ["19887b07-e9b8-4fa6-8369-64146226c454"]
    +  "total_message_count" : 100,
    +  "read_message_count" : 50
    +}
    +
    +
  • +
  • "/clusters/{clusterName}/instances/{instanceName}/messages/{messageId}

    +
      +
    • Represents the messages currently received by by the instance with message given message id. This is new endpoint in v2.0.
    • +
    • GET - get the message content with {messageId} received by the instance.
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/instances/localhost_1234/messages/0b8df4f2-776c-4325-96e7-8fad07bd9048
    +{
    +  "id": "0b8df4f2-776c-4325-96e7-8fad07bd9048",
    +  "CREATE_TIMESTAMP":"1489997469400",
    +  "ClusterEventName":"messageChange",
    +  "FROM_STATE":"OFFLINE",
    +  "MSG_ID":"0b8df4f2-776c-4325-96e7-8fad07bd9048",
    +  "MSG_STATE":"new",
    +  "MSG_TYPE":"STATE_TRANSITION",
    +  "PARTITION_NAME":"Resource1_243",
    +  "RESOURCE_NAME":"Resource1",
    +  "SRC_NAME":"controller_1234",
    +  "SRC_SESSION_ID":"15982390e5d5a76",
    +  "STATE_MODEL_DEF":"LeaderStandby",
    +  "STATE_MODEL_FACTORY_NAME":"myFactory",
    +  "TGT_NAME":"host_1234",
    +  "TGT_SESSION_ID":"459014c82efed9b",
    +  "TO_STATE":"DROPPED"
    +}
    +
    +
    +
  • +
  • “/clusters/{clusterName}/instances/{instanceName}/healthreports”

    +
      +
    • Represents all health reports in the instance in cluster {clusterName} with name {instanceName}. This is new endpoint in v2.0.
    • +
    • GET - return the name of health reports collected from the instance.
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/instances/host_1234/healthreports
    +{
    +  "id" : "host_1234",
    +  "healthreports" [ "report1", "report2", "report3" ]
    +}
    +
    +
  • +
  • “/clusters/{clusterName}/instances/{instanceName}/healthreports/{reportName}”

    +
      +
    • Represents the health report with {reportName} in the instance in cluster {clusterName} with name {instanceName}. This is new endpoint in v2.0.
    • +
    • GET - return the content of health report collected from the instance.
    • +
    +
    +
    $curl http://localhost:1234/admin/v2/clusters/myCluster/instances/host_1234/healthreports/ClusterStateStats
    +{
    +  "id":"ClusterStateStats"
    +  ,"simpleFields":{
    +    "CREATE_TIMESTAMP":"1466753504476"
    +    ,"TimeStamp":"1466753504476"
    +  }
    +  ,"listFields":{
    +  }
    +  ,"mapFields":{
    +    "UserDefinedData":{
    +      "Data1":"0"
    +      ,"Data2":"0.0"
    +    }
    +  }
    +}
    +
    +
  • +
+
+
+

Helix Workflow and its sub-resources

+ +
+
+

Helix Job and its sub-resources

+
    +
  • “/clusters/{clusterName}/workflows/{workflowName}/jobs”

    + +
    +
    {
    +    "id":"Jobs"
    +    "Jobs":["Job1","Job2","Job3"]
    +}
    +
    +
  • +
  • “/clusters/{clusterName}/workflows/{workflowName}/jobs/{jobName}”

    + +
    +
    {
    +    "id":"Job1"
    +    "JobConfig":{
    +        "WorkflowID":"Workflow1",
    +        "IgnoreDependentJobFailure":"false",
    +        "MaxForcedReassignmentsPerTask":"3"
    +    },
    +    "JobContext":{
    +	"START_TIME":"1491005863291",
    +        "FINISH_TIME":"149101.0.0612",
    +        "Tasks":[
    +             {
    +                 "id":"0",
    +                 "ASSIGNED_PARTICIPANT":"P1",
    +                 "FINISH_TIME":"1491005898905"
    +                 "INFO":""
    +                 "NUM_ATTEMPTS":"1"
    +                 "START_TIME":"1491005863307"
    +                 "STATE":"COMPLETED"
    +                 "TARGET":"DB_0"
    +             },
    +             {
    +                 "id":"1",
    +                 "ASSIGNED_PARTICIPANT":"P5",
    +                 "FINISH_TIME":"1491005895443"
    +                 "INFO":""
    +                 "NUM_ATTEMPTS":"1"
    +                 "START_TIME":"1491005863307"
    +                 "STATE":"COMPLETED"
    +                 "TARGET":"DB_1"
    +             }
    +         ]
    +     }
    +}
    +
    +
    +
  • +
  • “/clusters/{clusterName}/workflows/{workflowName}/jobs/{jobName}/configs”

    + +
    +
    {
    +  "id":"JobConfig"
    +  "WorkflowID":"Workflow1",
    +  "IgnoreDependentJobFailure":"false",
    +  "MaxForcedReassignmentsPerTask":"3"
    +}
    +
    +
  • +
  • “/clusters/{clusterName}/workflows/{workflowName}/jobs/{jobName}/context”

    + +
    +
    {
    +   "id":"JobContext":
    +   "START_TIME":"1491005863291",
    +   "FINISH_TIME":"149101.0.0612",
    +   "Tasks":[
    +             {
    +                 "id":"0",
    +                 "ASSIGNED_PARTICIPANT":"P1",
    +                 "FINISH_TIME":"1491005898905"
    +                 "INFO":""
    +                 "NUM_ATTEMPTS":"1"
    +                 "START_TIME":"1491005863307"
    +                 "STATE":"COMPLETED"
    +                 "TARGET":"DB_0"
    +             },
    +             {
    +                 "id":"1",
    +                 "ASSIGNED_PARTICIPANT":"P5",
    +                 "FINISH_TIME":"1491005895443"
    +                 "INFO":""
    +                 "NUM_ATTEMPTS":"1"
    +                 "START_TIME":"1491005863307"
    +                 "STATE":"COMPLETED"
    +                 "TARGET":"DB_1"
    +             }
    +   ]
    +}
    +
    +
  • +
+
+
+
+
+
+
+
+ +
+ + + + +
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+ + + + + + + + + + + + + + + + + + \ No newline at end of file Added: helix/site-content/0.9.5-docs/tutorial_spectator.html URL: http://svn.apache.org/viewvc/helix/site-content/0.9.5-docs/tutorial_spectator.html?rev=1877599&view=auto ============================================================================== --- helix/site-content/0.9.5-docs/tutorial_spectator.html (added) +++ helix/site-content/0.9.5-docs/tutorial_spectator.html Mon May 11 18:32:11 2020 @@ -0,0 +1,294 @@ + + + + + + + + Apache Helix - Tutorial - Spectator + + + + + + + + + + + + + + + + + + + + + + + + + +
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+ +

Next, we'll learn how to implement a spectator. Typically, a spectator needs to react to changes within the distributed system. Examples: a client that needs to know where to send a request, a topic consumer in a consumer group. The spectator is automatically informed of changes in the external state of the cluster, but it does not have to add any code to keep track of other components in the system.

+
+

Start a Connection

+

Same as for a participant, The Helix manager is the common component that connects each system component with the cluster.

+

It requires the following parameters:

+
    +
  • clusterName: A logical name to represent the group of nodes
  • +
  • instanceName: A logical name of the process creating the manager instance. Generally this is host:port
  • +
  • instanceType: Type of the process. This can be one of the following types, in this case, use SPECTATOR: +
      +
    • CONTROLLER: Process that controls the cluster, any number of controllers can be started but only one will be active at any given time
    • +
    • PARTICIPANT: Process that performs the actual task in the distributed system
    • +
    • SPECTATOR: Process that observes the changes in the cluster
    • +
    • ADMIN: To carry out system admin actions
    • +
  • +
  • zkConnectString: Connection string to ZooKeeper. This is of the form host1:port1,host2:port2,host3:port3
  • +
+

After the Helix manager instance is created, the only thing that needs to be registered is the listener. When the ExternalView changes, the listener is notified.

+

A spectator observes the cluster and is notified when the state of the system changes. Helix consolidates the state of entire cluster in one Znode called ExternalView. Helix provides a default implementation RoutingTableProvider that caches the cluster state and updates it when there is a change in the cluster.

+
+
manager = HelixManagerFactory.getZKHelixManager(clusterName,
+                                                instanceName,
+                                                InstanceType.SPECTATOR,
+                                                zkConnectString);
+manager.connect();
+RoutingTableProvider routingTableProvider = new RoutingTableProvider();
+manager.addExternalViewChangeListener(routingTableProvider);
+
+
+
+
+

Spectator Code

+

In the following code snippet, the application sends the request to a valid instance by interrogating the external view. Suppose the desired resource for this request is in the partition myDB_1.

+
+
// instances = routingTableProvider.getInstances(, "PARTITION_NAME", "PARTITION_STATE");
+instances = routingTableProvider.getInstances("myDB", "myDB_1", "ONLINE");
+
+////////////////////////////////////////////////////////////////////////////////////////////////
+// Application-specific code to send a request to one of the instances                        //
+////////////////////////////////////////////////////////////////////////////////////////////////
+
+theInstance = instances.get(0);  // should choose an instance and throw an exception if none are available
+result = theInstance.sendRequest(yourApplicationRequest, responseObject);
+
+
+
+

When the external view changes, the application needs to react by sending requests to a different instance.

+
+
+
+
+
+
+ +
+ + + + +
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+

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+ +

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+ +
+
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+
+
+ + + + + + + + + + + + + + + + + + \ No newline at end of file