Split Synchronizer

By default, FME's SDKs keep segment and feature flag data synchronized as users navigate across disparate systems, treatments, and conditions. However, some languages, do not have a native capability to keep a shared local cache of this data to properly serve treatments. For these cases, we built the Split Synchronizer service.

This tool coordinates the sending and receiving of data to a remote datastore that all of your processes can share to pull data for the evaluation of treatments. Out of the box, FME supports Redis as a remote datastore, and so the Split Synchronizer uses Redis as the cache for your SDKs when evaluating treatments. It also posts impression and event data and metrics generated by the SDKs back to Harness servers, for exposure in the user interface or sending to the data integration of your choice. The Synchronizer service runs as a standalone process in dedicated or shared servers and it does not affect the performance of your code, or FME's SDKs.

Split Synchronizer version 5.0 available!

Since version 5.0.0 of the split-synchronizer, there's only one operation mode. What was once proxy mode is now a separate tool called Split proxy. This version includes a more performant way to evict impressions & events from redis that allows customers to handle much greater volumes of data, while protecting your flags from being evicted if the redis instance runs low on memory.

Currently, the SDKs supported by this versions are: Ruby 6.0.0 PHP 6.0.0 Node.js 10.6.0 Go 3.0.0 Python 7.0.0 .NET 4.0.0 Java 4.4.0

warning

If you are upgrading from Split Synchronizer version 4.x or below to 5.x, some of the configuration and environment parameter names have been changed. Refer to the Configuration section and modify the parameters names accordingly.

Supported SDKs

The Split Synchronizer works with most of the languages that FME supports.

If you are looking for a language that is not listed here, contact the support team at support@split.io to discuss your options.

Overall Architecture

The service performs five actions:

Fetch feature flags: Retrieve the feature flag definitions.
Fetch segments: Retrieve your set segments lists.
Post impressions: Send to Harness servers the generated impressions by the SDK.
Post telemetry: Send to Harness servers different metrics of the SDK, such as latencies.
Post events: Send to Harness servers the generated events by the SDK .track method.

Split-Sync v5.0.0 pipelined data eviction

Starting with split-sync v5.0.0, we've introduced a new approach to impressions and events eviction. This replaces the previous approach of periodically fetching & posting impressions and events. Our new approch feature flags this task in 3 parts, a thread dedicated to fetching data from redis and placing it in a buffer, N threads (where N is derived from the number of available CPU cores) dedicated to parsing, formatting the data and placing it in a second buffer, and N (configurable) threads that pick the data and post it to Harness servers. The result is a significant increase in throughput, that will better suit customers which operate on big volumes of data.

Architecture

Setup

Docker (recommended)

The service is available via Docker or command line and its source code is available at https://github.com/splitio/split-synchronizer.

Pull the image: docker pull splitsoftware/split-synchronizer
Run as:

Running as Synchronizer
Running as Synchronizer with Sentinel
Running as Synchronizer with Cluster
Running as Synchronizer with AWS Redis Cluster

docker run --rm --name split-synchronizer \
 -p 3010:3010 \
 -e SPLIT_SYNC_APIKEY="your-sdk-key" \
 -e SPLIT_SYNC_REDIS_HOST=<your-redis-host> \
 -e SPLIT_SYNC_REDIS_PORT=<your_redis_port> \
 splitsoftware/split-synchronizer

docker run --rm --name split-synchronizer \
 -p 3010:3010 \
 -e SPLIT_SYNC_APIKEY="your-sdk-key" \
 -e SPLIT_SYNC_REDIS_SENTINEL_REPLICATION="true" \
 -e SPLIT_SYNC_REDIS_SENTINEL_MASTER="MASTER_SERVICE_NAME" \
 -e SPLIT_SYNC_REDIS_SENTINEL_ADDRESSES="SENTINEL_HOST_1:SENTINEL_PORT_1,SENTINEL_HOST_2:SENTINEL_PORT_2" \
 splitsoftware/split-synchronizer

docker run --rm --name split-synchronizer \
 -p 3010:3010 \
 -e SPLIT_SYNC_APIKEY="your-sdk-key" \
 -e SPLIT_SYNC_REDIS_CLUSTER_MODE="true" \
 -e SPLIT_SYNC_REDIS_CLUSTER_NODES="CLUSTER_NODE_1:CLUSTER_PORT_1,CLUSTER_NODE_2:CLUSTER_PORT_2,CLUSTER_NODE_3:CLUSTER_PORT_3" \
 splitsoftware/split-synchronizer

docker run --rm --name split-synchronizer \
 -p 3010:3010 \
 -e SPLIT_SYNC_APIKEY="your-sdk-key" \
 -e SPLIT_SYNC_REDIS_CLUSTER_MODE="true" \
 -e SPLIT_SYNC_REDIS_CLUSTER_NODES="Cluster Entry Host" \
 splitsoftware/split-synchronizer

Synchronizer mode with local redis instance

Sometimes, when building POCs or testing the synchronizer locally, you might want to launch our docker container image, pointing to a local redis server (or another container with redis, whose port has been mapped to a local one). In such case, you should consider adding the option --network="host" (appending it to the command shown above) when launching the synchronizer. This will allow you to use -e SPLIT_SYNC_REDIS_HOST="localhost", with the split-synchronizer container properly reaching your local redis server.

Docker configuration

The Advanced configuration section includes additional Docker information in the column Docker environment variable.

Command line

To install and run the service from command line, follow the steps below depending of your platform.

Linux

On Linux systems, the Synchronizer service install script is invoked with this.

curl -L -o install_linux.bin 'https://downloads.split.io/synchronizer/install_split_sync_linux.bin' && chmod 755 install_linux.bin && ./install_linux.bin

OSX

On OSX systems, the Synchronizer service install script is invoked with this.

curl -L -o install_osx.bin 'https://downloads.split.io/synchronizer/install_split_sync_osx.bin' && chmod 755 install_osx.bin && ./install_osx.bin

Windows

On Microsoft Windows systems, follow these steps:

Download the app from https://downloads.split.io/synchronizer/split_sync_windows.zip.
Unzip the downloaded file.
Run it!

Download previous versions

The links above point to the latest version. To download a previous version of split-sync, go to https://downloads.split.io/synchronizer/downloads.sync.html.

Run the service

To run the service, paste the snippet below into your command line terminal and add in your SDK-Key.

Linux/Mac

split-sync -apikey "your_sdk_key"

Windows

Open the cmd terminal or the PowerShell terminal, go to (cd) unzipped Split Synchronizer folder, and type:

split-sync.exe -apikey "your_sdk_key"

Redis instance

On the samples above, Redis is running as a local service with default host: localhost and default port: 6379. For further information, see Advanced configuration.

Redis database

To maximize performance and isolation, we recommend connecting to a Redis database dedicated to the Split Synchronizer. For further information, see Advanced configuration.

Redis Sentinel support

Split Synchronizer also supports Redis Sentinel (v2) replication. For further information about Redis Sentinel, refer to the Sentinel Documentation.

Redis Cluster support

Split Synchronizer supports Redis Cluster with Redis^3.0.0. For further information about Redis Cluster, refer to the Cluster Documentation.

Recommended configuration for production

You can run the service with the simple steps above, but the system is more stable in your production environment when you run the job with a scheduling system. We recommend starting the synchronizer via supervisord, a daemon that launches other processes and ensures they stay running.

To use supervisord, make sure that it is installed on your machine. You can get help on the installation at the official Supervisord documentation.

When supervisord is installed into your project, copy and paste the program below anywhere into the supervisord.conf file that should now be in your project.

[program:splitio_sync]
command=/usr/local/bin/split-sync -config /path/to/your/config.file.json
process_name = SplitIO
numprocs = 1
autostart=true
autorestart=true
user = your_user
stderr_logfile=/var/log/splitio.err.log
stderr_logfile_maxbytes = 1MB
stdout_logfile=/var/log/splitio.out.log
stdout_logfile_maxbytes = 1MB

Advanced configuration

The Synchronizer service has a number of knobs for configuring performance. Each knob is tuned to a reasonable default, however, you can override the default values by changing a splitio.config.json file or by setting your customer values as parameters of -config in the command line option. In this section, we lay out all the different knobs you can configure for performance, Redis, and logging.

The splitio.config.json file provided via the -config option lets you control how often the synchronizer fetches data from Harness servers. You can create a sample JSON file automatically with default values by running this command.

./split-sync -write-default-config "/home/someuser/splitio.config.json"

Configuration path file

Save the JSON config file on your server in your desired folder. For instance, on Linux systems, it could be saved in the etc folder. Remember to set the right path as the -config parameter.

splitio.config.json
splitio.sentinel.config.json
splitio.cluster.config.json

{
  "apikey": "YOUR_SDK_KEY",
  "ipAddressEnabled": true,
  "initialization": {
    "timeoutMS": 10000,
    "forceFreshStartup": false
  },
  "storage": {
    "type": "redis",
    "redis": {
      "host": "localhost",
      "port": 6379,
      "db": 0,
      "username": "",
      "password": "",
      "prefix": "",
      "network": "tcp",
      "maxRetries": 0,
      "dialTimeout": 5,
      "readTimeout": 10,
      "writeTimeout": 5,
      "poolSize": 10,
      "sentinelReplication": false,
      "sentinelAddresses": "",
      "sentinelMaster": "",
      "clusterMode": false,
      "clusterNodes": "",
      "keyHashTag": "",
      "enableTLS": false,
      "tlsServerName": "",
      "caCertificates": null,
      "tlsSkipNameValidation": false,
      "tlsClientCertificate": "",
      "tlsClientKey": ""
    }
  },
  "sync": {
    "splitRefreshRateMs": 60000,
    "segmentRefreshRateMs": 60000,
    "impressionsMode": "optimized",
    "advanced": {
      "streamingEnabled": true,
      "httpTimeoutMs": 30000,
      "internalTelemetryRateMs": 3600000,
      "telemetryPushRateMs": 60000,
      "impressionsFetchSize": 0,
      "impressionsProcessConcurrency": 0,
      "impressionsProcessBatchSize": 0,
      "impressionsPostConcurrency": 0,
      "impressionsPostSize": 0,
      "impressionsAccumWaitMs": 0,
      "eventsFetchSize": 0,
      "eventsProcessConcurrency": 0,
      "eventsProcessBatchSize": 0,
      "eventsPostConcurrency": 0,
      "eventsPostSize": 0,
      "eventsAccumWaitMs": 0
    }
  },
  "admin": {
    "host": "0.0.0.0",
    "port": 3010,
    "username": "",
    "password": "",
    "secureChecks": false
  },
  "integrations": {
    "impressionListener": {
      "endpoint": "",
      "queueSize": 100
    },
    "slack": {
      "webhook": "",
      "channel": ""
    }
  },
  "logging": {
    "level": "info",
    "output": "stdout",
    "rotationMaxFiles": 10,
    "rotationMaxSizeKb": 0
  },
  "healthcheck": {
    "app": {
      "storageCheckRateMs": 3600000
    }
  }
}

{
  "apikey": "YOUR_SDK_KEY",
  "ipAddressEnabled": true,
  "initialization": {
    "timeoutMS": 10000,
    "forceFreshStartup": false
  },
  "storage": {
    "type": "redis",
    "redis": {
      "host": "localhost",
      "port": 6379,
      "db": 0,
      "username": "",
      "password": "",
      "prefix": "",
      "network": "tcp",
      "maxRetries": 0,
      "dialTimeout": 5,
      "readTimeout": 10,
      "writeTimeout": 5,
      "poolSize": 10,
      "sentinelReplication": true,
      "sentinelAddresses": "SENTINEL_HOST_1:SENTINEL_PORT_1, SENTINEL_HOST_2:SENTINEL_PORT_2,SENTINEL_HOST_3:SENTINEL_PORT_3",
      "sentinelMaster": "MASTER_SERVICE_NAME",
      "clusterMode": false,
      "clusterNodes": "",
      "keyHashTag": "",
      "enableTLS": false,
      "tlsServerName": "",
      "caCertificates": null,
      "tlsSkipNameValidation": false,
      "tlsClientCertificate": "",
      "tlsClientKey": ""
    }
  },
  "sync": {
    "splitRefreshRateMs": 60000,
    "segmentRefreshRateMs": 60000,
    "impressionsMode": "optimized",
    "advanced": {
      "streamingEnabled": true,
      "httpTimeoutMs": 30000,
      "internalTelemetryRateMs": 3600000,
      "telemetryPushRateMs": 60000,
      "impressionsFetchSize": 0,
      "impressionsProcessConcurrency": 0,
      "impressionsProcessBatchSize": 0,
      "impressionsPostConcurrency": 0,
      "impressionsPostSize": 0,
      "impressionsAccumWaitMs": 0,
      "eventsFetchSize": 0,
      "eventsProcessConcurrency": 0,
      "eventsProcessBatchSize": 0,
      "eventsPostConcurrency": 0,
      "eventsPostSize": 0,
      "eventsAccumWaitMs": 0
    }
  },
  "admin": {
    "host": "0.0.0.0",
    "port": 3010,
    "username": "",
    "password": "",
    "secureChecks": false
  },
  "integrations": {
    "impressionListener": {
      "endpoint": "",
      "queueSize": 100
    },
    "slack": {
      "webhook": "",
      "channel": ""
    }
  },
  "logging": {
    "level": "info",
    "output": "stdout",
    "rotationMaxFiles": 10,
    "rotationMaxSizeKb": 0
  },
  "healthcheck": {
    "app": {
      "storageCheckRateMs": 3600000
    }
  }
}

{
  "apikey": "",
  "ipAddressEnabled": true,
  "initialization": {
    "timeoutMS": 10000,
    "forceFreshStartup": false
  },
  "storage": {
    "type": "redis",
    "redis": {
      "host": "localhost",
      "port": 6379,
      "db": 0,
      "username": "",
      "password": "",
      "prefix": "",
      "network": "tcp",
      "maxRetries": 0,
      "dialTimeout": 5,
      "readTimeout": 10,
      "writeTimeout": 5,
      "poolSize": 10,
      "sentinelReplication": false,
      "sentinelAddresses": "",
      "sentinelMaster": "",
      "clusterMode": true,
      "clusterNodes": "CLUSTER_NODE_1:CLUSTER_PORT_1, CLUSTER_NODE_2:CLUSTER_PORT_2,CLUSTER_NODE_3:CLUSTER_PORT_3",
      "keyHashTag": "",
      "enableTLS": false,
      "tlsServerName": "",
      "caCertificates": null,
      "tlsSkipNameValidation": false,
      "tlsClientCertificate": "",
      "tlsClientKey": ""
    }
  },
  "sync": {
    "splitRefreshRateMs": 60000,
    "segmentRefreshRateMs": 60000,
    "impressionsMode": "optimized",
    "advanced": {
      "streamingEnabled": true,
      "httpTimeoutMs": 30000,
      "internalTelemetryRateMs": 3600000,
      "telemetryPushRateMs": 60000,
      "impressionsFetchSize": 0,
      "impressionsProcessConcurrency": 0,
      "impressionsProcessBatchSize": 0,
      "impressionsPostConcurrency": 0,
      "impressionsPostSize": 0,
      "impressionsAccumWaitMs": 0,
      "eventsFetchSize": 0,
      "eventsProcessConcurrency": 0,
      "eventsProcessBatchSize": 0,
      "eventsPostConcurrency": 0,
      "eventsPostSize": 0,
      "eventsAccumWaitMs": 0
    }
  },
  "admin": {
    "host": "0.0.0.0",
    "port": 3010,
    "username": "",
    "password": "",
    "secureChecks": false
  },
  "integrations": {
    "impressionListener": {
      "endpoint": "",
      "queueSize": 100
    },
    "slack": {
      "webhook": "",
      "channel": ""
    }
  },
  "logging": {
    "level": "info",
    "output": "stdout",
    "rotationMaxFiles": 10,
    "rotationMaxSizeKb": 0
  },
  "healthcheck": {
    "app": {
      "storageCheckRateMs": 3600000
    }
  }
}

Command line parameters

All the options available in the JSON file are also included as command line options. Run the command followed by the -help option to see more details, or just keep reading this documentation page.

Methods to configure the Split Synchronizer

You can configure the Split Synchronizer service using the command line or by directly editing the above mentioned JSON configuration file.

Config values priority

All config values are set with a default value that you can see in the example JSON file above. You can overwrite the default value from the JSON config file, and you can overwrite the JSON config file from the command line. See a sample below for how to do that via command line.

split-sync -config "/etc/splitio.config.json" -log-level "debug" -redis-pass "somePass" 

CLI Configuration options and its equivalents in JSON & Environment variables

Split Synchronizer version 5.0 boolean options change

In order to reduce the issues because of typos and confusion due to "multiple words & case meaning the same", since version 5.0.0 of the split-synchronizer, the only accepted values for boolean flags are "true" & "false" in lowercase. Things like "enabled", "on", "yes", "tRue" will result in an error at startup. This applies to JSON, CLI arguments & environment variables.

Command line option	JSON option	Environment variable (container-only)	Description
log-level	level	SPLIT_SYNC_LOG_LEVEL	Log level (error\|warning\|info\|debug\|verbose)
log-output	output	SPLIT_SYNC_LOG_OUTPUT	Where to output logs (defaults to stdout)
log-rotation-max-files	rotationMaxFiles	SPLIT_SYNC_LOG_ROTATION_MAX_FILES	Max number of files to keep when rotating logs
log-rotation-max-size-kb	rotationMaxSizeKb	SPLIT_SYNC_LOG_ROTATION_MAX_SIZE_KB	Max file size before rotating log files.
admin-host	host	SPLIT_SYNC_ADMIN_HOST	Host where the admin server will listen
admin-port	port	SPLIT_SYNC_ADMIN_PORT	Admin port where incoming connections will be accepted
admin-username	username	SPLIT_SYNC_ADMIN_USERNAME	HTTP basic auth username for admin endpoints
admin-password	password	SPLIT_SYNC_ADMIN_PASSWORD	HTTP basic auth password for admin endpoints
admin-secure-hc	secureChecks	SPLIT_SYNC_ADMIN_SECURE_HC	Secure Healthcheck endpoints as well.
admin-tls-enabled	enabled	SPLIT_SYNC_ADMIN_TLS_ENABLED	Enable HTTPS on proxy endpoints.
admin-tls-client-validation	clientValidation	SPLIT_SYNC_ADMIN_TLS_CLIENT_VALIDATION	Enable client cert validation.
admin-tls-server-name	serverName	SPLIT_SYNC_ADMIN_TLS_SERVER_NAME	Server name as it appears in provided server-cert.
admin-tls-cert-chain-fn	certChainFn	SPLIT_SYNC_ADMIN_TLS_CERT_CHAIN_FN	X509 Server certificate chain.
admin-tls-private-key-fn	privateKeyFn	SPLIT_SYNC_ADMIN_TLS_PRIVATE_KEY_FN	PEM Private key file name.
admin-tls-client-validation-root-cert	clientValidationRootCertFn	SPLIT_SYNC_ADMIN_TLS_CLIENT_VALIDATION_ROOT_CERT	X509 root cert for client validation.
admin-tls-min-tls-version	minTlsVersion	SPLIT_SYNC_ADMIN_TLS_MIN_TLS_VERSION	Minimum TLS version to allow X.Y.
admin-tls-allowed-cipher-suites	allowedCipherSuites	SPLIT_SYNC_ADMIN_TLS_ALLOWED_CIPHER_SUITES	Comma-separated list of cipher suites to allow.
impression-listener-endpoint	endpoint	SPLIT_SYNC_IMPRESSION_LISTENER_ENDPOINT	HTTP endpoint to forward impressions to
impression-listener-queue-size	queueSize	SPLIT_SYNC_IMPRESSION_LISTENER_QUEUE_SIZE	max number of impressions bulks to queue
slack-webhook	webhook	SPLIT_SYNC_SLACK_WEBHOOK	slack webhook to post log messages
slack-channel	channel	SPLIT_SYNC_SLACK_CHANNEL	slack channel to post log messages
apikey	apikey	SPLIT_SYNC_APIKEY	Split Server-side SDK api-key
ip-address-enabled	ipAddressEnabled	SPLIT_SYNC_IP_ADDRESS_ENABLED	Bundle host's ip address when sending data to Harness FME
timeout-ms	timeoutMS	SPLIT_SYNC_TIMEOUT_MS	How long to wait until the synchronizer is ready
snapshot	snapshot	SPLIT_SYNC_SNAPSHOT	Snapshot file to use as a starting point
force-fresh-startup	forceFreshStartup	SPLIT_SYNC_FORCE_FRESH_STARTUP	Wipe storage before starting the synchronizer
storage-type	type	SPLIT_SYNC_STORAGE_TYPE	Storage driver to use for caching feature flags and segments and user-generated data
split-refresh-rate-ms	splitRefreshRateMs	SPLIT_SYNC_SPLIT_REFRESH_RATE_MS	How often to refresh feature flags
segment-refresh-rate-ms	segmentRefreshRateMs	SPLIT_SYNC_SEGMENT_REFRESH_RATE_MS	How often to refresh segments
impressions-mode	impressionsMode	SPLIT_SYNC_IMPRESSIONS_MODE	whether to send all impressions for debugging
streaming-enabled	streamingEnabled	SPLIT_SYNC_STREAMING_ENABLED	Enable/disable streaming functionality
http-timeout-ms	httpTimeoutMs	SPLIT_SYNC_HTTP_TIMEOUT_MS	Total http request timeout
internal-metrics-rate-ms	internalTelemetryRateMs	SPLIT_SYNC_INTERNAL_METRICS_RATE_MS	How often to send internal metrics
telemetry-push-rate-ms	telemetryPushRateMs	SPLIT_SYNC_TELEMETRY_PUSH_RATE_MS	how often to flush sdk telemetry
impressions-fetch-size	impressionsFetchSize	SPLIT_SYNC_IMPRESSIONS_FETCH_SIZE	Impression fetch bulk size
impressions-process-concurrency	impressionsProcessConcurrency	SPLIT_SYNC_IMPRESSIONS_PROCESS_CONCURRENCY	#Threads for processing imps
impressions-process-batch-size	impressionsProcessBatchSize	SPLIT_SYNC_IMPRESSIONS_PROCESS_BATCH_SIZE	Size of imp processing batchs
impressions-post-concurrency	impressionsPostConcurrency	SPLIT_SYNC_IMPRESSIONS_POST_CONCURRENCY	#concurrent imp post threads
impressions-post-size	impressionsPostSize	SPLIT_SYNC_IMPRESSIONS_POST_SIZE	Max #impressions to send per POST
impressions-accum-wait-ms	impressionsAccumWaitMs	SPLIT_SYNC_IMPRESSIONS_ACCUM_WAIT_MS	Max ms to wait to close an impressions bulk
events-fetch-size	eventsFetchSize	SPLIT_SYNC_EVENTS_FETCH_SIZE	How many impressions to pop from storage at once
events-process-concurrency	eventsProcessConcurrency	SPLIT_SYNC_EVENTS_PROCESS_CONCURRENCY	#Threads for processing imps
events-process-batch-size	eventsProcessBatchSize	SPLIT_SYNC_EVENTS_PROCESS_BATCH_SIZE	Size of imp processing batchs
events-post-concurrency	eventsPostConcurrency	SPLIT_SYNC_EVENTS_POST_CONCURRENCY	#concurrent imp post threads
events-post-size	eventsPostSize	SPLIT_SYNC_EVENTS_POST_SIZE	Max #impressions to send per POST
events-accum-wait-ms	eventsAccumWaitMs	SPLIT_SYNC_EVENTS_ACCUM_WAIT_MS	Max ms to wait to close an events bulk
redis-host	host	SPLIT_SYNC_REDIS_HOST	Redis server hostname
redis-port	port	SPLIT_SYNC_REDIS_PORT	Redis Server port
redis-db	db	SPLIT_SYNC_REDIS_DB	Redis DB
redis-pass	password	SPLIT_SYNC_REDIS_PASS	Redis password
redis-user	username	SPLIT_SYNC_REDIS_USER	Redis username
redis-prefix	prefix	SPLIT_SYNC_REDIS_PREFIX	Redis key prefix
redis-network	network	SPLIT_SYNC_REDIS_NETWORK	Redis network protocol
redis-max-retries	maxRetries	SPLIT_SYNC_REDIS_MAX_RETRIES	Redis connection max retries
redis-dial-timeout	dialTimeout	SPLIT_SYNC_REDIS_DIAL_TIMEOUT	Redis connection dial timeout
redis-read-timeout	readTimeout	SPLIT_SYNC_REDIS_READ_TIMEOUT	Redis connection read timeout
redis-write-timeout	writeTimeout	SPLIT_SYNC_REDIS_WRITE_TIMEOUT	Redis connection write timeout
redis-pool	poolSize	SPLIT_SYNC_REDIS_POOL	Redis connection pool size
redis-sentinel-replication	sentinelReplication	SPLIT_SYNC_REDIS_SENTINEL_REPLICATION	Redis sentinel replication enabled.
redis-sentinel-addresses	sentinelAddresses	SPLIT_SYNC_REDIS_SENTINEL_ADDRESSES	List of redis sentinels
redis-sentinel-master	sentinelMaster	SPLIT_SYNC_REDIS_SENTINEL_MASTER	Name of master
redis-cluster-mode	clusterMode	SPLIT_SYNC_REDIS_CLUSTER_MODE	Redis cluster enabled.
redis-cluster-nodes	clusterNodes	SPLIT_SYNC_REDIS_CLUSTER_NODES	List of redis cluster nodes.
redis-cluster-key-hashtag	keyHashTag	SPLIT_SYNC_REDIS_CLUSTER_KEY_HASHTAG	keyHashTag for redis cluster.
redis-tls	enableTLS	SPLIT_SYNC_REDIS_TLS	Use SSL/TLS for connecting to redis
redis-tls-server-name	tlsServerName	SPLIT_SYNC_REDIS_TLS_SERVER_NAME	Server name to use when validating a server public key
redis-tls-ca-certs	caCertificates	SPLIT_SYNC_REDIS_TLS_CA_CERTS	Root CA certificates to connect to a redis server via SSL/TLS
redis-tls-skip-name-validation	tlsSkipNameValidation	SPLIT_SYNC_REDIS_TLS_SKIP_NAME_VALIDATION	Blindly accept server's public key.
redis-tls-client-certificate	tlsClientCertificate	SPLIT_SYNC_REDIS_TLS_CLIENT_CERTIFICATE	Client certificate signed by a known CA
redis-tls-client-key	tlsClientKey	SPLIT_SYNC_REDIS_TLS_CLIENT_KEY	Client private key matching the certificate.
storage-check-rate-ms	storageCheckRateMs	SPLIT_SYNC_STORAGE_CHECK_RATE_MS	How often to check storage health
flag-sets-filter	flagSetsFilter	SPLIT_SYNC_FLAG_SETS_FILTER	This setting allows the Split Synchronizer to only synchronize the feature flags in the specified flag sets, avoiding unused or unwanted flags from being synced on the Split Synchronizer instance, bringing all the benefits from a reduced payload.

Listener

The Split Synchronizer provides an impression listener that bulks post impressions to a user-defined HTTP endpoint.

The endpoint should expect a POST request, containing a JSON body with the following format.

JSON Impression
{
 "impressions": [
  {
   "testName": "feature1",
   "keyImpressions": [
    {
     "keyName": "user1",
     "treatment": "on",
     "time": 1502754901182,
     "changeNumber": -1,
     "label": ""
    },
    {
     "keyName": "user2",
     "treatment": "off",
     "time": 1502754876144,
     "changeNumber": -1,
     "label": ""
    }
   ]
  }
 ],
 "sdkVersion": "php-5.2.2",
 "machineIP": "208.63.222.7",
 "MachineName": ""
}

Currently, the configuration options are available in the integrations.impressionListener section of the JSON configuration file detailed in Advanced configuration.

Using a network proxy

If you need to use a network proxy, configure proxies by setting the environment variables HTTP_PROXY and HTTPS_PROXY. The internal HTTP client reads those variables and uses them to perform the server request.

Example: Environment variables
$ export HTTP_PROXY="http://10.10.1.10:3128"
$ export HTTPS_PROXY="http://10.10.1.10:1080"

Admin tools

Endpoints

The split-sync service has a set of endpoints and a dashboard to let DevOps and infra team monitor its status and cached data in real-time. By default the port is 3010 and for security reason supports HTTP Basic Authentication configured by the user.

/info/ping

A ping endpoint to monitor the service status. If the service is running, it sends the text response pong and the HTTP status code 200.

/info/version

Returns the split-sync version in JSON format.

{
  "version" : "1.1.0"
}

/info/uptime

Returns the uptime string representation in JSON format.

{
  "uptime" : "5d 3h 36m 39s"
}

/info/config Returns a JSON object describing the current configuration of the Synchronizer.

{
  "config": {
    "apikey": "*",
    "ipAddressEnabled": true,
    "initialization": {
      "timeoutMS": 10000,
      "forceFreshStartup": false
    },
    "storage": {
      "type": "redis",
      "redis": {
        "host": "localhost",
        "port": 6379,
        "db": 0,
        "username": "",
        "password": "",
        "prefix": "",
        "network": "tcp",
        "maxRetries": 0,
        "dialTimeout": 5,
        "readTimeout": 10,
        "writeTimeout": 5,
        "poolSize": 10,
        "sentinelReplication": false,
        "sentinelAddresses": "",
        "sentinelMaster": "",
        "clusterMode": false,
        "clusterNodes": "",
        "keyHashTag": "",
        "enableTLS": false,
        "tlsServerName": "",
        "caCertificates": null,
        "tlsSkipNameValidation": false,
        "tlsClientCertificate": "",
        "tlsClientKey": ""
      }
    },
    "sync": {
      "splitRefreshRateMs": 60000,
      "segmentRefreshRateMs": 60000,
      "impressionsMode": "optimized",
      "advanced": {
        "streamingEnabled": true,
        "httpTimeoutMs": 30000,
        "internalTelemetryRateMs": 3600000,
        "telemetryPushRateMs": 60000,
        "impressionsFetchSize": 0,
        "impressionsProcessConcurrency": 0,
        "impressionsProcessBatchSize": 0,
        "impressionsPostConcurrency": 0,
        "impressionsPostSize": 0,
        "impressionsAccumWaitMs": 0,
        "eventsFetchSize": 0,
        "eventsProcessConcurrency": 0,
        "eventsProcessBatchSize": 0,
        "eventsPostConcurrency": 0,
        "eventsPostSize": 0,
        "eventsAccumWaitMs": 0
      }
    },
    "admin": {
      "host": "0.0.0.0",
      "port": 3010,
      "username": "",
      "password": "",
      "secureChecks": false
    },
    "integrations": {
      "impressionListener": {
        "endpoint": "",
        "queueSize": 100
      },
      "slack": {
        "webhook": "",
        "channel": ""
      }
    },
    "logging": {
      "level": "info",
      "output": "stdout",
      "rotationMaxFiles": 10,
      "rotationMaxSizeKb": 0
    },
    "healthcheck": {
      "app": {
        "storageCheckRateMs": 3600000
      }
    }
  }
}

/health/application Returns a JSON object describing whether the synchronizer is healthy or not.

{
  "healthy": true,
  "healthySince": "2021-11-20T19:04:46.528242-03:00",
  "items": [
    {
      "name": "Splits",
      "healthy": true,
      "lastHit": "2021-11-20T19:04:49.079956-03:00"
    },
    {
      "name": "Segments",
      "healthy": true,
      "lastHit": "2021-11-20T19:04:49.268349-03:00"
    },
    {
      "name": "Storage",
      "healthy": true
    }
  ]
}

/health/dependencies Returns a JSON object describing whether the servers the synchronizer depends on are healthy or not.

{
  "serviceStatus": "healthy",
  "dependencies": [
    {
      "service": "https://telemetry.split.io/health",
      "healthy": true,
      "healthySince": "2021-11-20T19:04:46.528262-03:00"
    },
    {
      "service": "https://auth.split.io/health",
      "healthy": true,
      "healthySince": "2021-11-20T19:04:46.528264-03:00"
    },
    {
      "service": "https://sdk.split.io/api/version",
      "healthy": true,
      "healthySince": "2021-11-20T19:04:46.528265-03:00"
    },
    {
      "service": "https://events.split.io/api/version",
      "healthy": true,
      "healthySince": "2021-11-20T19:04:46.528266-03:00"
    },
    {
      "service": "https://streaming.split.io/health",
      "healthy": true,
      "healthySince": "2021-11-20T19:04:46.528266-03:00"
    }
  ]
}

Admin Dashboard

Split-sync has a web admin UI out of the box that exposes all available endpoints. Browse to /admin/dashboard to see it.

The dashboard is organized in four sections for ease of visualization:

Dashboard: Tile-sorted summary information, including these metrics:
- Uptime: Uptime metric
- Healthy Since: Time passed without errors
- Logged Errors: Total count of error messages
- SDKs Total Hits: Total SDKs requests
- Backend Total Hits: Total backend requests between split-sync and Harness servers
- Cached Feature flags: Number of feature flags cached in memory
- Cached Segments: Number of segments cached in memory
- Impressions Queue Size: shows the total amount of Impressions stored in Redis (only Producer Mode).
- Impressions Lambda: shows the eviction rate for Impressions (only Producer Mode).
- Events Queue Size: shows the total amount of Events stored in Redis (only Producer Mode).
- Events Lambda: shows the eviction rate for Events (only Producer Mode).
- SDK Server: displays the status of Split server for SDK.
- Events Server: displays the status of Split server for Events.
- Streaming Server*: displays the status of Split streaming service
- Auth Server*: displays the status of Split server for initial streaming authentication
- Telemetry Server*: displays the status of Split server for telemetry capturing.
- Storage: (only Sync mode) displays the status of the storage.
- Sync: displays the status of the Synchronizer.
- Last Errors Log: List of the last 10 error messages
SDK stats: Metrics numbers and a latency graph, measured between SDKs requests integration and proxy.
Data inspector: Cached data showing feature flags and segments; filters to find keys and feature flag definitions.
Queue Manager: expose sizes of Impressions and Events queues.

Dashboard refresh rate

The dashboard numbers are committed every 60 seconds. The Logged Errors, Last Errors Log tiles, and the Data inspector section are populated each time the dashboard is refreshed. For Impressions and Events Queue size the numbers are refreshed every 10 seconds.

Service shutdown

The split-sync service can catch a kill sig command and start a graceful shutdown, flushing all cached data progressively. Additionally, you can perform graceful stop and force stop (kill -9) with one click from the admin dashboard.

If you have configured a Slack channel and the Slack Webhook URL, an alert is sent to the channel when and initialization or shutdown is performed.

Supported SDKs​

Overall Architecture​

Architecture​

Setup​

Docker (recommended)​

Command line​

Linux​

OSX​

Windows​

Run the service​

Linux/Mac​

Windows​

Recommended configuration for production​

Advanced configuration​

Methods to configure the Split Synchronizer​

CLI Configuration options and its equivalents in JSON & Environment variables​

Listener​

Using a network proxy​

Admin tools​

Endpoints​

Admin Dashboard​

Service shutdown​

Supported SDKs

Overall Architecture

Architecture

Setup

Docker (recommended)

Command line

Linux

OSX

Windows

Run the service

Linux/Mac

Windows

Recommended configuration for production

Advanced configuration

Methods to configure the Split Synchronizer

CLI Configuration options and its equivalents in JSON & Environment variables

Listener

Using a network proxy

Admin tools

Endpoints

Admin Dashboard

Service shutdown