### Start Pravega Segment Store Service with Metrics

Source: https://pravega.io/docs/latest/metrics

This example demonstrates starting the Pravega Segment Store service, where the Metrics Service is initiated as a sub-service. It is sourced from `io.pravega.segmentstore.server.host.ServiceStarter`.

```java
public static void main(String[] args) throws Exception {
    // ... other initializations ...
    SegmentStoreService.main(args);
    // ... other initializations ...
}
```

--------------------------------

### Example HelloWorldReader Output

Source: https://pravega.io/docs/latest/getting-started

This is an example of the output you might see when running the HelloWorldReader application.

```text
... 
Reading all the events from examples/helloStream
...
Read event 'hello world'
No more events from examples/helloStream
...

```

--------------------------------

### Append Setup - Reply

Source: https://pravega.io/docs/latest/wire-protocol

Server reply confirming the setup for an append operation.

```APIDOC
## Append Setup - Reply

This message is sent by the server to confirm that the append operation has been set up successfully.

### Fields

- **RequestId** (Long): The client-generated ID corresponding to the setup append request.
- **Segment** (String): The name of the Stream Segment to which data will be appended.
- **writerId** (UUID): The identifier of the requesting appender. This ID is used to route subsequent append blocks.
- **lastEventNumber** (Long): The number of the last event currently in the Stream Segment.
```

--------------------------------

### Example HelloWorldWriter Output

Source: https://pravega.io/docs/latest/getting-started

This is an example of the output you might see when running the HelloWorldWriter application.

```text
... 
Writing message: 'hello world' with routing-key: 'helloRoutingKey' to stream 'examples / helloStream'
...

```

--------------------------------

### Prerequisite Check: Java Version

Source: https://pravega.io/docs/latest/getting-started

Ensure Java 11 is installed before proceeding with Pravega setup.

```bash
Java 11

```

--------------------------------

### Install NFS Server Provisioner with Helm

Source: https://pravega.io/docs/latest/getting-started/pravega-on-kubernetes-101

Installs the NFS server provisioner using the stable Helm chart. Ensure Helm is configured with the stable repository.

```bash
helm repo add stable https://charts.helm.sh/stable
helm install stable/nfs-server-provisioner --generate-name

```

--------------------------------

### Get Scaling Events Request Path

Source: https://pravega.io/docs/latest/rest/restapis

Example path for retrieving scaling events within a specified time range.

```text
/scopes/string/streams/string/scaling-events?from=0&to=0
```

--------------------------------

### Example Table Segment Attribute Index Info

Source: https://pravega.io/docs/latest/recovery-procedures/table-segment-recovery

Example output from the 'table-segment get' command, showing metadata for an attribute index. Fields like version, length, and chunk count need to be updated during recovery.

```text
> table-segment get _system/containers/storage_metadata_3 _system/_tables/completedTransactionsBatch-0$attributes.index 127.0.1.1
For the given key: _system/_tables/completedTransactionsBatch-0$attributes.index
SLTS metadata info: 
key = _system/_tables/completedTransactionsBatch-0$attributes.index;
version = 1654241463251;
metadataType = SegmentMetadata;
name = _system/_tables/completedTransactionsBatch-0$attributes.index;
length = 13488706;
chunkCount = 3;
startOffset = 13135328;
status = 1;
maxRollingLength = 128767;
firstChunk = _system/_tables/completedTransactionsBatch-0$attributes.index.E-5-O-13131945.29bd2254-2e77-4338-a41a-f9c2af07b913;
lastChunk = _system/_tables/completedTransactionsBatch-0$attributes.index.E-5-O-13389479.5779f8d5-89ad-4bc6-87fe-3f99480a7271;
lastModified = 0;
firstChunkStartOffset = 13131945;
lastChunkStartOffset = 13389479;
ownerEpoch = 5;

    One would edit the following fields to update the metadata to reflect the chunk properties we have in step 6b).

            - Increment the version.
            - Update the length to reflect the cumulative length of chunk(s). In our example since there is just one Attribute chunk as seen in listing of step 5 we would update it length which is 458 (bytes).
            - Update the chunk count. in the case above it is 1, since there is just one chunk generated by the command in step 4.
            - Update the startOffset to 0.
            - Update the firstChunk to the one generated in step 4, which is `completedTransactionsBatch-0$attributes.index.E-1-O-0.7a9a16d4-cab6-4e5d-9173-d441d9656149`
            - Update the lastChunk to the same as firstChunk there is only one chunk. 
            - Update the firstChunkStartOffset to 0. Derived from "E-1-[O]-0" part in file name.
            - Update the lastChunkStartOffset to 0. (first and last chunks are same.)

    This is how the resulting put command would look like:
```

--------------------------------

### Start Bookkeeper Service

Source: https://pravega.io/docs/latest/deployment/manual-install

Start the Bookkeeper service (bookie) after performing necessary formatting.

```bash
bin/bookkeeper bookie
```

--------------------------------

### Example HTTP Request Path for Fetching Stream Properties

Source: https://pravega.io/docs/latest/rest/restapis

This is an example of the request path to fetch the properties of a specific stream. Replace 'string' with your actual scope and stream names.

```http
/scopes/string/streams/string
```

--------------------------------

### Example Request Body for Creating a Stream

Source: https://pravega.io/docs/latest/rest/restapis

This is an example of a request body for creating a stream. It includes optional configurations for scaling, retention policy, and other stream properties.

```json
{
  "streamName" : "string",
  "scalingPolicy" : {
    "type" : "string",
    "targetRate" : 0,
    "scaleFactor" : 0,
    "minSegments" : 0
  },
  "retentionPolicy" : {
    "type" : "string",
    "value" : 0,
    "timeBasedRetention" : {
      "days" : 0,
      "hours" : 0,
      "minutes" : 0
    },
    "maxValue" : 0,
    "maxTimeBasedRetention" : {
      "days" : 0,
      "hours" : 0,
      "minutes" : 0
    }
  },
  "streamTags" : { },
  "timestampAggregationTimeout" : { },
  "rolloverSizeBytes" : { }
}
```

--------------------------------

### Global Metric Naming Example

Source: https://pravega.io/docs/latest/metrics

Example of a global metric name using the _global suffix.

```text
  segmentstore.segment.read_bytes_global
```

--------------------------------

### Build Pravega samples

Source: https://pravega.io/docs/latest/getting-started/pravega-on-kubernetes-101

Commands to access the pod, install dependencies, and build the sample applications.

```bash
kubectl exec -it test-pod -- /bin/bash 
apt-get update 
apt-get -y install git-core openjdk-8-jdk 
git clone -b r0.8 https://github.com/pravega/pravega-samples 
cd pravega-samples 
./gradlew installDist 
```

--------------------------------

### Start Pravega Standalone from Package

Source: https://pravega.io/docs/latest/beginner_dev_guide

Commands to extract the release package and launch the standalone server.

```bash
tar xfvz pravega-<version>.tgz
```

```bash
pravega-<version>/bin/pravega-standalone
```

--------------------------------

### Launch Pravega from Installation Package

Source: https://pravega.io/docs/latest/deployment/run-local

Extract the release tarball and execute the standalone startup script.

```bash
$ tar xfvz pravega-<version>.tgz
```

```bash
$ pravega-<version>/bin/pravega-standalone
```

--------------------------------

### Initialize Metrics Provider

Source: https://pravega.io/docs/latest/metrics

Initialize the MetricsProvider with configuration before starting the stats provider. This should be done when starting a Segment Store or Controller service.

```java
MetricsProvider.initialize(Config.METRICS_CONFIG);
statsProvider.start(metricsConfig);
statsProvider = MetricsProvider.getMetricsProvider();
statsProvider.start();
```

--------------------------------

### Start Pravega standalone cluster

Source: https://pravega.io/docs/latest/getting-started/quick-start

Launch the Pravega standalone server process.

```bash
./bin/pravega-standalone
```

--------------------------------

### Install Pravega Cluster with Helm

Source: https://pravega.io/docs/latest/getting-started/pravega-on-kubernetes-101

Installs the Pravega cluster using the default Helm chart. This command assumes the Pravega operator is already deployed.

```bash
helm install pravega pravega/pravega

```

--------------------------------

### Start from Specific StreamCuts

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/stream/ReaderGroupConfig.ReaderGroupConfigBuilder.html

Ensures that readers in the reader group begin processing from the provided map of StreamCuts. This allows for setting distinct starting points for multiple streams.

```java
public ReaderGroupConfig.ReaderGroupConfigBuilder startFromStreamCuts(java.util.Map<Stream, StreamCut> streamCuts)
```

--------------------------------

### Object-based Metric Naming Example

Source: https://pravega.io/docs/latest/metrics

Example of an object-based metric name including specific tags for granularity.

```text
segmentstore.segment.read_bytes, ["scope", "...", "stream", "...", "segment", "...", "epoch", "..."])
```

--------------------------------

### TransactionalEventStreamWriter.beginTxn()

Source: https://pravega.io/docs/latest/javadoc/clients/index-all.html

Starts a new transaction on the event stream writer.

```APIDOC
## beginTxn()

### Description
Start a new transaction on this stream.

### Method
Method in interface io.pravega.client.stream.TransactionalEventStreamWriter
```

--------------------------------

### Run Pravega Controller (after config)

Source: https://pravega.io/docs/latest/deployment/manual-install

Start the Pravega Controller after configuring its Zookeeper connection in `conf/controller.conf`.

```bash
bin/pravega-controller
```

--------------------------------

### Stream Output Example

Source: https://pravega.io/docs/latest/clients-and-streams

Expected output from the tail reader loop.

```text
4
5
6
null
```

--------------------------------

### Example HTTP Response for Listing Reader Groups

Source: https://pravega.io/docs/latest/rest/restapis

This is an example of a successful HTTP response when listing reader groups. It returns a JSON object containing a list of reader group names.

```json
{
  "readerGroups" : [ "object" ]
}
```

--------------------------------

### Setup Append - Request

Source: https://pravega.io/docs/latest/wire-protocol

Client request to initiate an append operation to a stream segment.

```APIDOC
## Setup Append - Request

This message is sent by a client to prepare for appending data to a stream segment.

### Fields

- **RequestId** (Long): The client-generated ID for this request.
- **writerId** (UUID): A unique identifier for the appender initiating the operation.
- **Segment** (String): The name of the Stream Segment to which data will be appended.
- **delegationToken** (String): An authentication token provided by the Controller, granting permission for this operation.
```

--------------------------------

### Get Configuration

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/stream/EventStreamWriter.html

Retrieves the configuration that the event writer was created with.

```APIDOC
## GET /config

### Description
Returns the configuration that this writer was create with.

### Method
GET

### Endpoint
/config

### Parameters
None

### Request Example
(No request body for GET request)

### Response
#### Success Response (200)
- **EventWriterConfig** (object) - Writer configuration

#### Response Example
{
  "retryAttempts": 3,
  "automaticallyNoteTime": false
}
```

--------------------------------

### Run HelloWorldReader Sample Application

Source: https://pravega.io/docs/latest/getting-started

Execute the HelloWorldReader application to read events from the 'examples/helloStream'. Ensure you are in the correct directory after running installDist.

```bash
cd pravega-samples/pravega-client-examples/build/install/pravega-client-examples
./bin/helloWorldReader

```

--------------------------------

### Run HelloWorldWriter Sample Application

Source: https://pravega.io/docs/latest/getting-started

Execute the HelloWorldWriter application to send a 'hello world' message to a Pravega stream. Ensure you are in the correct directory after running installDist.

```bash
cd pravega-samples/pravega-client-examples/build/install/pravega-client-examples
./bin/helloWorldWriter

```

--------------------------------

### Get Writer Configuration

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/stream/IdempotentEventStreamWriter.html

Retrieves the configuration used to initialize the writer.

```java
EventWriterConfig getConfig()
```

--------------------------------

### Get Initial Backoff Millis

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/tables/KeyValueTableClientConfiguration.html

Retrieves the initial backoff duration in milliseconds used for retries. This setting influences the starting delay in a backoff strategy.

```java
public int getInitialBackoffMillis()
```

--------------------------------

### Add Stream with Default Start

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/stream/ReaderGroupConfig.ReaderGroupConfigBuilder.html

Configures a reader group to read from a specific stream using its current starting position. Use this when the default starting point of the stream is acceptable.

```java
public ReaderGroupConfig.ReaderGroupConfigBuilder stream(Stream stream)
```

--------------------------------

### Bootstrap Java Application

Source: https://pravega.io/docs/latest/beginner_dev_guide

Initialize a new Java application project using Gradle.

```bash
gradle init --type java-application
```

--------------------------------

### Clone and Build Pravega from Source

Source: https://pravega.io/docs/latest/deployment/run-local

Download the source code and build the standalone distribution.

```bash
$ git clone https://github.com/pravega/pravega.git
$ cd pravega
```

```bash
./gradlew startStandalone
```

--------------------------------

### Create the test pod

Source: https://pravega.io/docs/latest/getting-started/pravega-on-kubernetes-101

Command to deploy the test pod using the provided manifest file.

```bash
kubectl create -f test-pod.yaml 
```

--------------------------------

### Add Stream with Start StreamCut

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/stream/ReaderGroupConfig.ReaderGroupConfigBuilder.html

Configures a reader group to read from a specific stream, starting at a defined StreamCut. The end of the stream is implied. Use this when you need to specify a starting point but not an explicit end.

```java
public ReaderGroupConfig.ReaderGroupConfigBuilder stream(Stream stream, StreamCut startStreamCut)
```

--------------------------------

### Configure Client Security

Source: https://pravega.io/docs/latest/security/securing-standalone-mode-cluster

Example of building a ClientConfig with TLS and authentication credentials for a secure Pravega connection.

```java
 ClientConfig clientConfig = ClientConfig.builder()
              .controllerURI(URI.create("tls://localhost:9090"))

               // TLS-related client-side configuration
              .trustStore("/path/to/ca-cert.crt")
              .validateHostName(false)

               // Auth-related client-side configuration
              .credentials(new DefaultCredentials(this.password, this.username))

              .build();
```

--------------------------------

### Create Scope and Stream via CLI

Source: https://pravega.io/docs/latest/getting-started/quick-start

Initialize a scope and a stream using the Pravega CLI tool.

```text
./bin/pravega-cli
> scope create my-scope
> stream create my-scope/my-stream
```

--------------------------------

### Install Zookeeper Operator

Source: https://pravega.io/docs/latest/getting-started/pravega-on-kubernetes-101

Install the Zookeeper Operator using the Pravega Helm chart. This is the first step to manage Zookeeper clusters in Kubernetes.

```bash
helm install zookeeper-operator pravega/zookeeper-operator

```

--------------------------------

### Navigate to Configuration Directory

Source: https://pravega.io/docs/latest/security/securing-standalone-mode-cluster

Commands to change directory to the Pravega configuration folder.

```bash
$ cd /path/to/pravega/config
```

```bash
$ cd /path/to/pravega-<version>/conf
```

--------------------------------

### Initialize and Join a Reader Group

Source: https://pravega.io/docs/latest/reader-group-design

Create a client factory and instantiate a reader that joins a specific reader group by name.

```java
ClientFactory clientFactory = ClientFactory.withScope(scope, controllerURI);
EventStreamReader< T > reader = clientFactory.createReader(readerId, READER_GROUP_NAME, serializer, readerConfig);
```

--------------------------------

### KeyValueTableClientConfiguration Builder Methods

Source: https://pravega.io/docs/latest/javadoc/clients/index-all.html

Methods for configuring a KeyValueTable client, including initial backoff.

```APIDOC
## KeyValueTableClientConfiguration Builder

### Methods

#### `initialBackoffMillis(int)`

Sets the initial backoff in milliseconds used in the retry logic.

### Class
io.pravega.client.tables.KeyValueTableClientConfiguration.KeyValueTableClientConfigurationBuilder
```

--------------------------------

### Initialize KeyValueTableInfo

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/admin/KeyValueTableInfo.html

Constructor for creating a new KeyValueTableInfo instance with a specified scope and table name.

```java
@ConstructorProperties({"scope","keyValueTableName"})
public KeyValueTableInfo​(java.lang.String scope,
                         java.lang.String keyValueTableName)
```

--------------------------------

### Clone Pravega Samples Repository

Source: https://pravega.io/docs/latest/getting-started

Download the Pravega Samples git repository to access example applications.

```bash
$ git clone https://github.com/pravega/pravega-samples
cd pravega-samples

```

--------------------------------

### Add Stream with Start and End StreamCuts

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/stream/ReaderGroupConfig.ReaderGroupConfigBuilder.html

Configures a reader group to read from a specific stream, starting and ending at defined StreamCuts. Use this when precise control over the read range within a stream is required.

```java
public ReaderGroupConfig.ReaderGroupConfigBuilder stream(Stream stream, StreamCut startStreamCut, StreamCut endStreamCut)
```

--------------------------------

### Example HTTP Response for Reader Group Properties

Source: https://pravega.io/docs/latest/rest/restapis

This is an example of a successful HTTP response when fetching reader group properties. It includes the scope name, reader group name, and associated stream list.

```json
{
  "scopeName" : "string",
  "readerGroupName" : "string",
  "streamList" : [ "string" ],
  "onlineReaderIds" : [ "string" ]
}
```

--------------------------------

### Generate Java Keystore with Keytool

Source: https://pravega.io/docs/latest/security/generating-tls-artifacts

Commands for creating a JKS keystore for server authentication. Passwords can be provided as command-line arguments or entered interactively.

```bash
# Passwords are passed as command line arguments.
$ keytool -keystore server01.keystore.jks -alias server01 -validity <validity> -genkey \
            -storepass <keystore-password> -keypass <key-password> \
            -dname <distinguished-name> -ext SAN=DNS:<hostname>,
```

```bash
# Passwords (and some other arguments) are to be entered interactively on the prompt.
$ keytool -keystore server01.keystore.jks -alias server01 -genkey
```

--------------------------------

### GET /admin/listScopes

Source: https://pravega.io/docs/latest/javadoc/clients/index-all.html

Retrieves an iterator for all available scopes.

```APIDOC
## GET /admin/listScopes

### Description
Gets an iterator for all scopes defined in the system.

### Method
GET
```

--------------------------------

### Create KeyValueTable Client

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/KeyValueTableFactory.html

Method to create a client for a specific Key-Value Table using the provided configuration.

```java
KeyValueTable forKeyValueTable​(@NonNull
                               @NonNull java.lang.String keyValueTableName,
                               @NonNull
                               @NonNull KeyValueTableClientConfiguration clientConfiguration)
```

--------------------------------

### GET /scopes

Source: https://pravega.io/docs/latest/rest/restapis

List all available scopes in Pravega.

```APIDOC
## GET /scopes

### Description
List all available scopes in Pravega.

### Method
GET

### Endpoint
/scopes

### Response
#### Success Response (200)
- **ScopesList** (object) - List of currently available scopes.

#### Response Example
{
  "scopes": [
    {
      "scopeName": "string"
    }
  ]
}

```

--------------------------------

### Run Pravega Controller

Source: https://pravega.io/docs/latest/deployment/manual-install

Start the Pravega Controller service. Replace `<zk-ip>` with the IP address of your Zookeeper nodes.

```bash
ZK_URL=<zk-ip>:2181 bin/pravega-controller
```

--------------------------------

### Configure Authentication Parameters

Source: https://pravega.io/docs/latest/security/securing-standalone-mode-cluster

Set these properties in standalone-config.properties to enable authentication.

```properties
singlenode.security.auth.enable=true
singlenode.security.auth.credentials.username=admin
singlenode.security.auth.credentials.pwd=1111_aaaa
singlenode.security.auth.pwdAuthHandler.accountsDb.location=../config/passwd
```

--------------------------------

### GET /health/status

Source: https://pravega.io/docs/latest/rest/restapis

Fetch the status of the Controller service.

```APIDOC
## GET /health/status

### Description
Fetch the status of the Controller service.

### Method
GET

### Endpoint
/health/status

### Response
#### Success Response (200)
- **HealthStatus** (object) - The health status of the Controller.

#### Response Example
{}

```

--------------------------------

### Configure SSL/TLS Parameters

Source: https://pravega.io/docs/latest/security/securing-standalone-mode-cluster

Set these properties in standalone-config.properties to enable and configure SSL/TLS.

```properties
singlenode.security.tls.enable=true
singlenode.security.tls.protocolVersion=TLSv1.2,TLSv1.3
singlenode.security.tls.privateKey.location=../config/server-key.key
singlenode.security.tls.certificate.location=../config/server-cert.crt
singlenode.security.tls.keyStore.location=../config/server.keystore.jks
singlenode.security.tls.keyStore.pwd.location=../config/server.keystore.jks.passwd
singlenode.security.tls.trustStore.location=../config/client.truststore.jks
```

--------------------------------

### Get Notification Type

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/stream/notifications/Observable.html

Retrieves the type of the notification.

```APIDOC
## GET /getType

### Description
Get the notification type.

### Method
GET

### Endpoint
/getType

### Response
#### Success Response (200)
* **notificationType** (String) - The type of the notification.
```

--------------------------------

### GET /stream/configuration/tags

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/stream/StreamConfiguration.html

Retrieves the tags configured for the Stream.

```APIDOC
## GET /stream/configuration/tags

### Description
Returns the set of tags configured for the Stream.

### Method
GET

### Response
#### Success Response (200)
- **tags** (Set<String>) - A list of tags associated with the Stream.
```

--------------------------------

### Import Certificate to Truststore

Source: https://pravega.io/docs/latest/security/securing-standalone-mode-cluster

Import the certificate into the JVM truststore using keytool.

```bash
$ sudo keytool -importcert -alias local-CA \
     -keystore /path/to/jre/lib/security/cacerts  -file ca-cert.der
```

--------------------------------

### Start Pravega Admin CLI

Source: https://pravega.io/docs/latest/recovery-procedures/lts-recovery-steps

Launch the Pravega admin CLI tool. This tool is used to perform various administrative tasks, including data recovery.

```bash
./bin/pravega-admin
```

--------------------------------

### GET /transaction/status

Source: https://pravega.io/docs/latest/javadoc/clients/index-all.html

Retrieves the current status of a specific transaction.

```APIDOC
## GET /transaction/status

### Description
Get the status of a transaction.

### Method
GET

### Endpoint
io.pravega.client.stream.TransactionInfo.getTransactionStatus()
```

--------------------------------

### GET /admin/stream-tags

Source: https://pravega.io/docs/latest/javadoc/clients/index-all.html

Retrieves the tags associated with a specific stream.

```APIDOC
## GET /admin/stream-tags

### Description
Gets the Tags associated with a stream.

### Method
GET

### Endpoint
/admin/stream-tags

### Parameters
#### Query Parameters
- **scope** (String) - Required - The scope name of the stream.
- **streamName** (String) - Required - The name of the stream.
```

--------------------------------

### GET /scopes/{scopeName}

Source: https://pravega.io/docs/latest/rest/restapis

Retrieve details of an existing scope.

```APIDOC
## GET /scopes/{scopeName}

### Description
Retrieve details of an existing scope.

### Method
GET

### Endpoint
/scopes/{scopeName}

### Parameters
#### Path Parameters
- **scopeName** (string) - Required - Scope name.

### Response
#### Success Response (200)
- **ScopeProperty** (object) - Successfully retrieved the scope details.

#### Response Example
{
  "scopeName": "string"
}

```

--------------------------------

### initialize

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/state/StateSynchronizer.html

Initializes the state for a new stream.

```APIDOC
## initialize

### Description
Provides an initial value for a new stream if it has not been previously initialized.

### Parameters
- **initial** (InitialUpdate<StateT>) - Required - The initializer for the state.
```

--------------------------------

### Install Bookkeeper Cluster

Source: https://pravega.io/docs/latest/getting-started/pravega-on-kubernetes-101

Deploy a Bookkeeper cluster using the publicly available Helm chart. This command quickly sets up a Bookkeeper cluster.

```bash
helm install bookkeeper pravega/bookkeeper

```

--------------------------------

### GET /health/readiness

Source: https://pravega.io/docs/latest/rest/restapis

Fetches the readiness state of the Controller service.

```APIDOC
## GET /health/readiness

### Description
Fetch the ready state of the Controller service.

### Method
GET

### Endpoint
/health/readiness

### Response
#### Success Response (200)
- **status** (boolean) - The ready status.

#### Response Example
true
```

--------------------------------

### GET /health/liveness

Source: https://pravega.io/docs/latest/rest/restapis

Fetches the liveness state of the Controller service.

```APIDOC
## GET /health/liveness

### Description
Fetch the liveness state of the Controller service.

### Method
GET

### Endpoint
/health/liveness

### Response
#### Success Response (200)
- **status** (boolean) - The alive status.

#### Response Example
true
```

--------------------------------

### GET /stream/configuration/rollover-size

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/stream/StreamConfiguration.html

Retrieves the segment rollover size for the Stream.

```APIDOC
## GET /stream/configuration/rollover-size

### Description
Returns the segment rollover size in bytes. A value of 0 indicates the server default will be used.

### Method
GET

### Response
#### Success Response (200)
- **rolloverSizeBytes** (long) - The rollover size for the segment.
```

--------------------------------

### Inspect Keystore Contents

Source: https://pravega.io/docs/latest/security/generating-tls-artifacts

Use keytool to list and verify the contents of a JKS keystore file.

```bash
$ keytool -list -v -storepass changeit -keystore server.keystore.jks
```

--------------------------------

### GET /stream/configuration/retention-policy

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/stream/StreamConfiguration.html

Retrieves the retention policy configured for the Stream.

```APIDOC
## GET /stream/configuration/retention-policy

### Description
Returns the retention policy associated with the Stream configuration.

### Method
GET

### Response
#### Success Response (200)
- **RetentionPolicy** (object) - The retention policy object for the Stream.
```

--------------------------------

### Run Pravega Segment Store

Source: https://pravega.io/docs/latest/deployment/manual-install

Start the Pravega Segment Store service after applying the necessary configuration changes.

```bash
bin/pravega-segmentstore
```

--------------------------------

### Execute the console writer

Source: https://pravega.io/docs/latest/getting-started/pravega-on-kubernetes-101

Commands to navigate to the build directory and run the console writer against the Pravega controller.

```bash
cd pravega-client-examples/build/install/pravega-client-examples/ 
bin/consoleWriter -u tcp://pravega-pravega-controller:9090
```

--------------------------------

### GET /stream/configuration/scaling-policy

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/stream/StreamConfiguration.html

Retrieves the scaling policy configured for the Stream.

```APIDOC
## GET /stream/configuration/scaling-policy

### Description
Returns the scaling policy associated with the Stream configuration.

### Method
GET

### Response
#### Success Response (200)
- **ScalingPolicy** (object) - The scaling policy object for the Stream.
```

--------------------------------

### Create KeyValueTableFactory Instance

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/KeyValueTableFactory.html

Static method to initialize a factory instance for a given scope and configuration.

```java
static KeyValueTableFactory withScope​(java.lang.String scope,
                                      ClientConfig config)
```

--------------------------------

### Deploy Pravega with Docker Compose

Source: https://pravega.io/docs/latest/deployment/run-local

Commands to download, configure, and start a distributed Pravega deployment using Docker Compose.

```bash
$ wget https://raw.githubusercontent.com/pravega/pravega/master/docker/compose/docker-compose.yml
```

```bash
$ git clone https://github.com/pravega/pravega.git
```

```bash
$ cd /path/to/pravega/docker/compose
```

```bash
$ export HOST_IP=<HOST_IP>
```

```bash
$ docker-compose up -d
```

```bash
$ docker-compose up -d -f docker-compose-nfs.yml
```

```bash
$ docker-compose ps
```

--------------------------------

### Implement HelloWorldReader run method

Source: https://pravega.io/docs/latest/basic-reader-and-writer

This method initializes the stream manager, configures the reader group, and continuously reads events from the specified stream until no more events are available.

```java
public void run() {
    StreamManager streamManager = StreamManager.create(controllerURI);

    final boolean scopeIsNew = streamManager.createScope(scope);
    StreamConfiguration streamConfig = StreamConfiguration.builder()
            .scalingPolicy(ScalingPolicy.fixed(1))
            .build();
   final boolean streamIsNew = streamManager.createStream(scope, streamName, streamConfig);

   final String readerGroup = UUID.randomUUID().toString().replace("-", "");
   final ReaderGroupConfig readerGroupConfig = ReaderGroupConfig.builder()
            .stream(Stream.of(scope, streamName))
            .build();
    try (ReaderGroupManager readerGroupManager = ReaderGroupManager.withScope(scope, controllerURI))
    {
        readerGroupManager.createReaderGroup(readerGroup, readerGroupConfig);
    }

    try (ClientFactory clientFactory = ClientFactory.withScope(scope, controllerURI);
        EventStreamReader<String> reader = clientFactory.createReader("reader",
                readerGroup,
                new JavaSerializer<String>(),
                ReaderConfig.builder().build()))
    {
        System.out.format("Reading all the events from %s/%s%n", scope, streamName);
        EventRead<String> event = null;
        do {
            try {
                event = reader.readNextEvent(READER_TIMEOUT_MS);
                if (event.getEvent() != null) {
                    System.out.format("Read event '%s'%n", event.getEvent());
                }
            } catch (ReinitializationRequiredException e) {
                //There are certain circumstances where the reader needs to be reinitialized
                e.printStackTrace();
            }
        } while (event.getEvent() != null);
        System.out.format("No more events from %s/%s%n", scope, streamName);
    }
}
```

--------------------------------

### GET /admin/listCompletedTransactions

Source: https://pravega.io/docs/latest/javadoc/clients/index-all.html

Lists recently completed transactions for a specific stream.

```APIDOC
## GET /admin/listCompletedTransactions

### Description
List most recent completed (COMMITTED/ABORTED) transactions for a given stream.

### Method
GET

### Parameters
#### Query Parameters
- **stream** (Stream) - Required - The stream to query for completed transactions.
```

--------------------------------

### GET /admin/listKeyValueTables

Source: https://pravega.io/docs/latest/javadoc/clients/index-all.html

Retrieves an iterator for all Key-Value Tables within a scope.

```APIDOC
## GET /admin/listKeyValueTables

### Description
Gets an iterator for all Key-Value Tables in the given scope.

### Method
GET

### Parameters
#### Query Parameters
- **scope** (String) - Required - The scope to list Key-Value Tables from.
```

--------------------------------

### GET /notification/type

Source: https://pravega.io/docs/latest/javadoc/clients/index-all.html

Retrieves the notification type for various observable components.

```APIDOC
## GET /notification/type

### Description
Get the notification type.

### Method
GET

### Endpoint
io.pravega.client.stream.notifications.Observable.getType()
```

--------------------------------

### GET /health/status/{id}

Source: https://pravega.io/docs/latest/rest/restapis

Fetch the status of a specific health contributor.

```APIDOC
## GET /health/status/{id}

### Description
Fetch the status of a specific health contributor.

### Method
GET

### Endpoint
/health/status/{id}

### Parameters
#### Path Parameters
- **id** (string) - Required - The id of an existing health contributor.

### Response
#### Success Response (200)
- **HealthStatus** (object) - The health status of the Controller.

#### Response Example
{}

```

--------------------------------

### Initialize Zookeeper Paths for Pravega

Source: https://pravega.io/docs/latest/deployment/manual-install

Create necessary paths in Zookeeper for Pravega and Bookkeeper. Replace `<$ZK_URL>` with the actual Zookeeper node IP address.

```bash
bin/zkCli.sh -server $ZK_URL create /pravega
bin/zkCli.sh -server $ZK_URL create /pravega/bookkeeper
```

--------------------------------

### GET /health/details

Source: https://pravega.io/docs/latest/rest/restapis

Fetches the detailed health information of the Controller service.

```APIDOC
## GET /health/details

### Description
Fetch the details of the Controller service.

### Method
GET

### Endpoint
/health/details

### Response
#### Success Response (200)
- **details** (object) - The list of details.

#### Response Example
{ }
```

--------------------------------

### Client Factory Initialization

Source: https://pravega.io/docs/latest/javadoc/clients/index-all.html

Methods to create instances of various Pravega client factories using a scope and configuration or URI.

```APIDOC
## Static Method: withScope

### Description
Creates a new instance of a client factory or manager for a given scope.

### Parameters
- **scope** (String) - Required - The scope name.
- **config** (ClientConfig) - Required - The client configuration.
- **uri** (URI) - Required - The controller URI.

### Supported Interfaces
- ReaderGroupManager
- BatchClientFactory
- ByteStreamClientFactory
- EventStreamClientFactory
- KeyValueTableFactory
- SynchronizerClientFactory
```

--------------------------------

### Builder Pattern

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/tables/KeyValueTableConfiguration.html

Demonstrates how to use the builder pattern to create a KeyValueTableConfiguration object.

```APIDOC
## POST /KeyValueTableConfiguration/builder

### Description
Creates a builder for KeyValueTableConfiguration.

### Method
POST

### Endpoint
/KeyValueTableConfiguration/builder

### Request Body
(No request body specified for builder creation)

### Response
#### Success Response (200)
- **builder** (KeyValueTableConfiguration.KeyValueTableConfigurationBuilder) - The builder instance.

#### Response Example
```json
{
  "builder": "KeyValueTableConfiguration.KeyValueTableConfigurationBuilder"
}
```
```

--------------------------------

### GET /health

Source: https://pravega.io/docs/latest/rest/restapis

Returns the overall health status of the Controller service.

```APIDOC
## GET /health

### Description
Return the Health of the Controller service.

### Method
GET

### Endpoint
/health

### Response
#### Success Response (200)
- **name** (string) - Service name
- **status** (object) - Status object
- **readiness** (boolean) - Readiness status
- **liveness** (boolean) - Liveness status
- **details** (object) - Health details
- **children** (object) - Child health results

#### Response Example
{
  "name" : "string",
  "status" : { },
  "readiness" : true,
  "liveness" : true,
  "details" : { },
  "children" : {
    "string" : "[healthresult](#healthresult)"
  }
}
```

--------------------------------

### KeyValueTableClientConfiguration Builder

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/tables/KeyValueTableClientConfiguration.html

Use the builder() method to obtain a builder instance for creating KeyValueTableClientConfiguration objects. This is the entry point for configuring client-side settings.

```java
public static KeyValueTableClientConfiguration.KeyValueTableClientConfigurationBuilder builder()
```

--------------------------------

### GET /readerGroup/segmentDistribution

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/stream/ReaderGroup.html

Returns the current distribution of segments assigned to each reader.

```APIDOC
## GET /readerGroup/segmentDistribution

### Description
Returns current distribution of number of segments assigned to each reader in the reader group.

### Method
GET

### Response
#### Success Response (200)
- **distribution** (ReaderSegmentDistribution) - Instance describing the distribution of segments.
```

--------------------------------

### Initialize DynamicLogger

Source: https://pravega.io/docs/latest/metrics

Obtain a dynamic logger instance from the MetricsProvider to begin tracking dynamic metrics.

```java
 DynamicLogger dynamicLogger = MetricsProvider.getDynamicLogger();
```

--------------------------------

### Deploy Client Application in Swarm

Source: https://pravega.io/docs/latest/deployment/docker-swarm

Command to deploy a client application into the pravega_default network.

```bash
docker service create --name=myapp --network=pravega_default mycompany/myapp
```

```bash
--network=pravega_default.
```

--------------------------------

### GET /listKeyValueTables

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/admin/KeyValueTableManager.html

Retrieves an iterator for all Key-Value Tables in a given scope.

```APIDOC
## GET /listKeyValueTables

### Description
Gets an iterator for all Key-Value Tables in the given scope.

### Parameters
#### Query Parameters
- **scopeName** (String) - Required - The name of the scope for which to list Key-Value Tables.

### Response
#### Success Response (200)
- **result** (Iterator<KeyValueTableInfo>) - An Iterator of KeyValueTableInfo objects.
```

--------------------------------

### POST /initialize

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/state/StateSynchronizer.html

Initializes a new stream with a provided initial state if the stream has not been previously initialized.

```APIDOC
## POST /initialize

### Description
This method can be used to provide an initial value for a new stream if the stream has not been previously initialized.

### Method
POST

### Endpoint
/initialize

### Parameters
#### Request Body
* **initial** (InitialUpdate<StateT>) - The initial state update for the stream.

### Request Example
```json
{
  "initial": "initial state update object"
}
```

### Response
#### Success Response (200)
* **void** - This method does not return a value upon successful completion.

#### Response Example
(No response body for void methods)
```

--------------------------------

### Define a TimeWindow

Source: https://pravega.io/docs/latest/watermarking

Example of defining a time window using two watermarks.

```java
TimeWindow T1 = {W1.lowerbound, W2.upperbound}
```

--------------------------------

### GET /health/{id}

Source: https://pravega.io/docs/latest/rest/restapis

Return the Health of a health contributor with a given id.

```APIDOC
## GET /health/{id}

### Description
Return the Health of a health contributor with a given id.

### Method
GET

### Endpoint
/health/{id}

### Parameters
#### Path Parameters
- **id** (string) - Required - The id of an existing health contributor.

### Response
#### Success Response (200)
- **HealthResult** (object) - The Health result of the Controller.

#### Response Example
{
  "name": "string",
  "status": {},
  "readiness": true,
  "liveness": true,
  "details": {},
  "children": {
    "string": "[healthresult](#healthresult)"
  }
}

```

--------------------------------

### GET /health/readiness/{id}

Source: https://pravega.io/docs/latest/rest/restapis

Fetches the readiness state of a specific health contributor.

```APIDOC
## GET /health/readiness/{id}

### Description
Fetch the ready state of the health contributor.

### Method
GET

### Endpoint
/health/readiness/{id}

### Parameters
#### Path Parameters
- **id** (string) - Required - The id of an existing health contributor.

### Response
#### Success Response (200)
- **status** (boolean) - The readiness status for the health contributor.
```

--------------------------------

### GET /health/liveness/{id}

Source: https://pravega.io/docs/latest/rest/restapis

Fetches the liveness state of a specific health contributor.

```APIDOC
## GET /health/liveness/{id}

### Description
Fetch the liveness state of the specified health contributor.

### Method
GET

### Endpoint
/health/liveness/{id}

### Parameters
#### Path Parameters
- **id** (string) - Required - The id of an existing health contributor.

### Response
#### Success Response (200)
- **status** (boolean) - The alive status for the specified health contributor.

#### Response Example
true
```

--------------------------------

### GET /health/details/{id}

Source: https://pravega.io/docs/latest/rest/restapis

Fetches the health details for a specific health contributor.

```APIDOC
## GET /health/details/{id}

### Description
Fetch the details of a specific health contributor.

### Method
GET

### Endpoint
/health/details/{id}

### Parameters
#### Path Parameters
- **id** (string) - Required - The id of an existing health contributor.

### Response
#### Success Response (200)
- **details** (object) - The list of details for the health contributor.

#### Response Example
{ }
```

--------------------------------

### Begin Transaction

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/stream/TransactionalEventStreamWriter.html

Starts a new transaction. Events written within this transaction can be committed atomically. Transactions have a limited timeout.

```java
Transaction<Type> beginTxn()
```

--------------------------------

### GET /health/readiness Request and Response

Source: https://pravega.io/docs/latest/rest/restapis

Check the readiness state of the Controller service.

```text
/health/readiness
```

```json
true
```

--------------------------------

### Client Configuration Builders

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/ClientConfig.ClientConfigBuilder.html

Methods for building and configuring ClientConfig instances.

```APIDOC
## ClientConfig.ClientConfigBuilder

### Description
Provides methods to configure various aspects of the Pravega client.

### Methods

#### validateHostName

##### Description
If the flag `ClientConfig.isEnableTls()` is set, this flag decides whether to enable host name validation or not.

##### Parameters
- **validateHostName** (boolean) - Required - Flag to decide whether to enable host name validation or not.

##### Returns
- `this` (ClientConfig.ClientConfigBuilder)

#### isDefaultMaxConnections

##### Description
An internal property that determines if the client config.

##### Parameters
- **isDefaultMaxConnections** (boolean) - Required - determines if the client config

##### Returns
- `this` (ClientConfig.ClientConfigBuilder)

#### metricListener

##### Description
An optional listener which can be used to get performance metrics from the client. The user can implement this interface to obtain performance metrics of the client.

##### Parameters
- **metricListener** (io.pravega.shared.metrics.MetricListener) - Optional - Listener to collect client performance metrics.

##### Returns
- `this` (ClientConfig.ClientConfigBuilder)

#### toString

##### Description
Returns a string representation of the object.

##### Overrides
- `toString` in class `java.lang.Object`
```

--------------------------------

### Start from Checkpoint

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/stream/ReaderGroupConfig.ReaderGroupConfigBuilder.html

Configures the reader group to resume reading from a previously saved Checkpoint. This is useful for fault tolerance and continuing processing from a known state.

```java
public ReaderGroupConfig.ReaderGroupConfigBuilder startFromCheckpoint(Checkpoint checkpoint)
```

--------------------------------

### GET /health/liveness Request and Response

Source: https://pravega.io/docs/latest/rest/restapis

Check the liveness state of the Controller service.

```text
/health/liveness
```

```json
true
```

--------------------------------

### Get All Table Entries

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/tables/KeyValueTable.html

Retrieves the latest values for a collection of `TableKey`s from the KeyValueTable.

```APIDOC
## POST /api/keyvaluestable/getAll

### Description
Retrieves the latest values for a set of `TableKey`s from the `KeyValueTable`.

### Method
POST

### Endpoint
/api/keyvaluestable/getAll

### Parameters
#### Request Body
- **keys** (Iterable<TableKey>) - Required - An `Iterable` of `TableKey`s to get values for.

### Request Example
```json
{
  "keys": [
    {
      "tableName": "myTable",
      "key": "key1"
    },
    {
      "tableName": "myTable",
      "key": "key2"
    }
  ]
}
```

### Response
#### Success Response (200)
- **entries** (List<TableEntry>) - A List of `TableEntry` instances for the requested keys. The size of the list matches `keys.size()`. Null entries correspond to keys that do not exist.

#### Response Example
```json
{
  "entries": [
    {
      "key": {
        "tableName": "myTable",
        "key": "key1"
      },
      "value": "value1",
      "version": "123e4567-e89b-12d3-a456-426614174000"
    },
    null
  ]
}
```
```

--------------------------------

### Create SynchronizerClientFactory Instance

Source: https://pravega.io/docs/latest/javadoc/clients/io/pravega/client/SynchronizerClientFactory.html

Static method to initialize a new factory instance with a specified scope and configuration.

```java
static SynchronizerClientFactory withScope​(java.lang.String scope,
                                           ClientConfig config)
```