# sherlock **Repository Path**: mirrors_yahoo/sherlock ## Basic Information - **Project Name**: sherlock - **Description**: Sherlock is an anomaly detection service built on top of Druid - **Primary Language**: Unknown - **License**: GPL-3.0 - **Default Branch**: master - **Homepage**: None - **GVP Project**: No ## Statistics - **Stars**: 0 - **Forks**: 0 - **Created**: 2020-08-19 - **Last Updated**: 2026-10-22 ## Categories & Tags **Categories**: Uncategorized **Tags**: None ## README # Sherlock: Anomaly Detector [![build](https://github.com/yahoo/sherlock/actions/workflows/main.yml/badge.svg?branch=master)](https://github.com/yahoo/sherlock/actions/workflows/main.yml) [![Maven Central](https://img.shields.io/maven-central/v/com.yahoo.sherlock/sherlock.svg)](https://central.sonatype.com/artifact/com.yahoo.sherlock/sherlock) [![Coverage Status](https://coveralls.io/repos/github/yahoo/sherlock/badge.svg?branch=master)](https://coveralls.io/github/yahoo/sherlock) [![GPL 3.0](https://img.shields.io/badge/license-GPL%203.0-blue.svg?style=flat)](LICENSE) ## Table of Contents * [Introduction](#introduction-to-sherlock) * [Components](#components) * [Detailed Description](#detailed-description) * [How to build](#how-to-build) * [Build JAR](#build-jar) * [How to run](#how-to-run) * [CLI args usage](#cli-args-usage) * [Committers](#committers) * [Contributors](#contributors) * [License](#license) ## Introduction to Sherlock Sherlock is an anomaly detection service built on top of [Druid](http://druid.io/). It leverages [EGADS (Extensible Generic Anomaly Detection System)](https://github.com/yahoo/egads) to detect anomalies in time-series data. Users can schedule jobs on an hourly, daily, weekly, or monthly basis, view anomaly reports from Sherlock's interface, or receive them via email. ## Components 1. [Timeseries Generation](#timeseries-generation) 2. [EGADS Anomaly Detection](#egads-anomaly-detection) 3. [Redis database](#redis-database) 4. [UI in Spark Java](#ui-in-spark-java) ## Detailed Description ### Timeseries Generation Timeseries generation is the first phase of Sherlock's anomaly detection. The user inputs a full Druid JSON query with a metric name and group-by dimensions. Sherlock validates the query, adjusts the time interaval and granularity based on the EGADS config, and makes a call to Druid. Druid responds with an array of time-series, which are parsed into EGADS time-series. #### Sample Druid Query: ```json { "metric": "metric(metric1/metric2)", "aggregations": [ { "filter": { "fields": [ { "type": "selector", "dimension": "dim1", "value": "value1" } ], "type": "or" }, "aggregator": { "fieldName": "metric2", "type": "longSum", "name": "metric2" }, "type": "filtered" } ], "dimension": "groupByDimension", "intervals": "2017-09-10T00:00:01+00:00/2017-10-12T00:00:01+00:00", "dataSource": "source1", "granularity": { "timeZone": "UTC", "type": "period", "period": "P1D" }, "threshold": 50, "postAggregations": [ { "fields": [ { "fieldName": "metric1", "type": "fieldAccess", "name": "metric1" } ], "type": "arithmetic", "name": "metric(metric1/metric2)", "fn": "/" } ], "queryType": "topN" } ``` #### Sample Druid Response: ```json [ { "timestamp" : "2017-10-11T00:00:00.000Z", "result" : [ { "groupByDimension" : "dim1", "metric(metric1/metric2)" : 8, "metric1" : 128, "metric2" : 16 }, { "groupByDimension" : "dim2", "metric(metric1/metric2)" : 4.5, "metric1" : 42, "metric2" : 9.33 } ] }, { "timestamp" : "2017-10-12T00:00:00.000Z", "result" : [ { "groupByDimension" : "dim1", "metric(metric1/metric2)" : 9, "metric1" : 180, "metric2" : 20 }, { "groupByDimension" : "dim2", "metric(metric1/metric2)" : 5.5, "metric1" : 95, "metric2" : 17.27 } ] } ] ``` ### EGADS Anomaly Detection Sherlock calls the user-configured EGADS API for each generated time-series, generates anomaly reports from the response, and stores these reports in a database. Users may also elect to receive anomaly reports by email. ### Redis Database Sherlock uses a Redis backend [Redis](https://redis.io/) to store job metadata, generated anomaly reports, among other information, and as a persistent job queue. Keys related to Reports have retention policy. Hourly job reports have retention of 14 days and daily/weekly/monthly job reports have 1 year of retention. ### Sherlock UI Sherlock's user interface is built with [Spark](http://sparkjava.com/). The UI enables users to submit instant anomaly analyses, create and launch detection jobs, view anomalies on a heatmap, and on a graph. ## Building Sherlock A `Makefile` is provided with all build targets. ### Building the JAR ```bash make jar ``` This creates `sherlock.jar` in the `target/` directory. ### How to run Sherlock is run through the commandline with config arguments. ```bash java -Dlog4j.configuration=file:${path_to_log4j}/log4j.properties \ -jar ${path_to_jar}/sherlock.jar \ --version $(VERSION) \ --project-name $(PROJECT_NAME) \ --port $(PORT) \ --enable-email \ --failure-email $(FAILURE_EMAIL) \ --from-mail $(FROM_MAIL) \ --reply-to $(REPLY_TO) \ --smtp-host $(SMTP_HOST) \ --interval-minutes $(INTERVAL_MINUTES) \ --interval-hours $(INTERVAL_HOURS) \ --interval-days $(INTERVAL_DAYS) \ --interval-weeks $(INTERVAL_WEEKS) \ --interval-months $(INTERVAL_MONTHS) \ --egads-config-filename $(EGADS_CONFIG_FILENAME) \ --redis-host $(REDIS_HOSTNAME) \ --redis-port $(REDIS_PORT) \ --execution-delay $(EXECUTION_DELAY) \ --timeseries-completeness $(TIMESERIES_COMPLETENESS) ``` ### CLI args usage | args | required | default | description | |---------------------------------------|---------------------|---------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------| | --help | - | `false` | [help](#help) | | --config | - | `null` | [config](#config) | | --version | - | `v0.0.0` | [version](#version) | | --egads-config-filename | - | `provided` | [egads-config-filename](#egads-config-filename) | | --port | - | `4080` | [port](#port) | | --interval-minutes | - | `180` | [interval-minutes](#interval-minutes) | | --interval-hours | - | `672` | [interval-hours](#interval-hours) | | --interval-days | - | `28` | [interval-days](#interval-days) | | --interval-weeks | - | `12` | [interval-weeks](#interval-weeks) | | --interval-months | - | `6` | [interval-months](#interval-months) | | --enable-email | - | `false` | [enable-email](#enable-email) | | --from-mail | if email `enabled` | | [from-mail](#from-mail) | | --reply-to | if email `enabled` | | [reply-to](#reply-to) | | --smtp-host | if email `enabled` | | [smtp-host](#smtp-host) | | --smtp-port | - | `25` | [smtp-port](#smtp-port) | | --smtp-user | - | | [smtp-user](#smtp-user) | | --smtp-password | - | | [smtp-password](#smtp-password) | | --failure-email | if email `enabled` | | [failure-email](#failure-email) | | --execution-delay | - | `30` | [execution-delay](#execution-delay) | | --valid-domains | - | `null` | [valid-domains](#valid-domains) | | --redis-host | - | `127.0.0.1` | [redis-host](#redis-host) | | --redis-port | - | `6379` | [redis-port](#redis-port) | | --redis-ssl | - | `false` | [redis-ssl](#redis-ssl) | | --redis-timeout | - | `5000` | [redis-timeout](#redis-timeout) | | --redis-password | - | - | [redis-password](#redis-password) | | --redis-clustered | - | `false` | [redis-clustered](#redis-clustered) | | --project-name | - | - | [project-name](#project-name) | | --external-file-path | - | - | [external-file-path](#external-file-path) | | --debug-mode | - | `false` | [debug-mode](#debug-mode) | | --timeseries-completeness | - | `60` | [timeseries-completeness](#timeseries-completeness) | | --http-client-timeout | - | `20000` | [http-client-timeout](#http-client-timeout) | | --backup-redis-db-path | - | `null` | [backup-redis-db-path](#backup-redis-db-path) | | --druid-brokers-list-file | - | `null` | [druid-brokers-list-file](#druid-brokers-list-file) | | --truststore-path | - | `null` | [truststore-path](#truststore-path) | | --truststore-type | - | `jks` | [truststore-type](#truststore-type) | | --truststore-password | - | `null` | [truststore-password](#truststore-password) | | --keystore-path | - | `null` | [keystore-path](#keystore-path) | | --keystore-type | - | `jks` | [keystore-type](#keystore-type) | | --keystore-password | - | `null` | [keystore-password](#keystore-password) | | --key-dir | - | `null` | [key-dir](#key-dir) | | --cert-dir | - | `null` | [cert-dir](#cert-dir) | | --https-hostname-verification | - | `true` | [https-hostname-verification](#https-hostname-verification) | | --custom-ssl-context-provider-class | - | [`DefaultSslContextProvider`](https://github.com/yahoo/sherlock/tree/master/src/main/java/com/yahoo/sherlock/utils) | [custom-ssl-context-provider-class](#custom-ssl-context-provider-class) | | --custom-secret-provider-class | - | [`DefaultSecretProvider`](https://github.com/yahoo/sherlock/tree/master/src/main/java/com/yahoo/sherlock/utils) | [custom-secret-provider-class](#custom-secret-provider-class) | | --prophet-url | - | `127.0.0.1:4080` | [prophet-url](#prophet-url) | | --prophet-timeout | - | `120000` | [prophet-timeout](#prophet-timeout) | | --prophet-principal | - | `prophet-principal` | [prophet-principal](#prophet-principal) | #### help Prints commandline argument help message. #### config Path to a Sherlock configuration file, where the above configuration may be specified. Config arguments in the file override commandline arguments. #### version Version of `sherlock.jar` to display on the UI #### egads-config-filename Path to a custom EGADS configuration file. If none is specified, the default configuration is used. #### port Port on which to host the Spark application. #### interval-minutes Number of historic data points to use for detection on time-series every minute. #### interval-hours Number of historic data points to use for detection on hourly time-series. #### interval-days Number of historic data points to use for detection on daily time-series. #### interval-weeks Number of historic data points to use for detection on weekly time-series. #### interval-months Number of historic data points to use for detection on monthly time-series. #### enable-email Enable the email service. This enables users to receive email anomaly report notifications. #### from-mail The handle's `FROM` email displayed to email recipients. #### reply-to The handle's `REPLY TO` email where replies will be sent. #### smtp-host The email service's `SMTP HOST`. #### smtp-port The email service's `SMTP PORT`. The default value is `25`. #### smtp-user The email service's `SMTP USER`. #### smtp-password The email service's `SMTP PASSWORD`. #### failure-email A dedicated email which may be set to receive job failure notifications. #### execution-delay Sherlock periodically pings Redis to check scheduled jobs. This sets the ping delay in seconds. Jobs are scheduled with a precision of one minute. #### valid-domains A comma-separated list of valid domains to receive emails, e.g. 'yahoo,gmail,hotmail'. If specified, Sherlock will restrict who may receive emails. #### redis-host The Redis backend hostname. #### redis-port The Redis backend port. #### redis-ssl Whether Sherlock should connect to Redis via SSL. #### redis-timeout The Redis connection timeout. #### redis-password The password to use when authenticating to Redis. #### redis-clustered Whether the Redis backend is a cluster. #### project-name Name of the project to display on UI. #### external-file-path Specify the path to external files for Spark framework via this argument. #### debug-mode Debug mode enables debug routes. Ex. '/DatabaseJson' (shows redis data as json dump). Look at `com.yahoo.sherlock.App` for more details. #### timeseries-completeness This defines minimum fraction of datapoints needed in the timeseries to consider it as a valid timeseries o/w sherlock ignores such timeseries. (default value 60 i.e. 0.6 in fraction) #### http-client-timeout HttpClient timeout can be configured using this(in millis). (default value 20000) #### backup-redis-db-path Backup redis DB at given file path as json dump of indices and objects. Backup is done per day at midnight. Default this parameter is null i.e. no buckup. However, BGSAVE command is run at midnight to save redis local dump. #### druid-brokers-list-file Specify the path to an access control list file of permitted druid broker hosts for querying. Format: `:,:...` (default null i.e any host is allowed) #### truststore-path Path to specify truststore location for mTLS connections. (default `null`) #### truststore-type Param to specify truststore type for mTLS connections. (default `jks`) #### truststore-password Param to specify truststore password for mTLS connections. (default `null`) #### keystore-path Path to specify keystore location for mTLS connections. (default `null`) #### keystore-type Param to specify keystore type for mTLS connections. (default `jks`) #### keystore-password Param to specify keystore password for mTLS connections. (default `null`) #### key-dir Param to specify key directory containing multiple keys(for different clusters) for mTLS connections (default `null`). This is used when `Principal Name` is given in druid cluster form. It looks for filename containing `Principal Name` under this dir. If `--key-dir` and `--cert-dir` values are same then the filename should also contain the identifier `key` for private key file and `cert` for public key file. #### cert-dir Param to specify cert directory containing multiple certs(for different clusters) for mTLS connections (default `null`)." This is used when `Principal Name` is given in druid cluster form. It looks for file name containing `Principal Name` under this dir. If `--key-dir` and `--cert-dir` values are same then the filename should also contain the identifier `key` for private key file and `cert` for public key file. #### https-hostname-verification Param to enable/disable https hostname verification for mTLS connections. (default `true` i.e. hostname verification enabled) #### custom-ssl-context-provider-class Param to specify custom ssl context provider class for mTLS connections. (default `com.yahoo.sherlock.utils.DefaultSslContextProvider` which returns SSLContext with validation) #### custom-secret-provider-class Param to specify custom secret provider class for passwords. (default `com.yahoo.sherlock.utils.DefaultSecretProvider` which returns secrets specified from CLISettings) #### prophet-url API endpoint of a running Prophet Service. (default `127.0.0.1:4080` which include both url and port) #### prophet-timeout Timeout for querying the Prophet Service. (default `120000` milliseconds) #### prophet-principal The Kubernetes principal that the Prophet Service is located. (default `prophet-principal`) ## Getting started It is suggested to use Java8 and Maven 3.3 to develop Sherlock. ## Further Development ### Adding a new anomaly detector to Sherlock Currently, Sherlock supports two detector pipelines (Egads/Prophet). Both pipelines use Egads' anomaly detection module for anomaly detection. The Egads pipeline conducts both time series forecasting and anomaly detection via Egads anomaly detection library. On the other hand, the Prophet pipeline allows Sherlock to query forecasted time series from a Prophet web service. After that, the Prophet pipeline performs anomaly detection via Egads' anomaly detection module. If the developer wants to add a new anomaly detector to Sherlock, the developer should look at the abstract class `service/DetectorAPIService.java`, and implement a new detector class that extends `DetectorAPIService`. More specifically, developers should implement abstract methods `detectAnomaliesAndForecast` and `detectAnomalies`. The two abstract methods are elaborated in sections below. ### Developing the instant detection feature Sherlock allows the user to perform an instant anomaly detection, which is accessible via the /Flash-Query endpoint. The endpoint is linked to method `processInstantAnomalyJob` under `Routes.java`, which calls method `detectWithResults` under `DetectorService.java`. Method `detectWithResults` checks which detector the user wants to use, assign the corresponding `DetectorAPIService` instance, and calls the instance's `detectAnomaliesAndForecast` method. Method `detectAnomaliesAndForecast` does anomaly detection and returns the original time series, expected time series, and the anomaly points. The combined results are displayed via the /Flash-Query/ProcessAnomalyReport endpoint. ### Developing the Job Scheduling feature Sherlock allows the user to schedule anomaly detection jobs that run routinely. Regarding the job scheduling, Sherlock uses `JobScheduler.java` to maintain a Priority Queue stored in Redis. Every time the user adds a job, Sherlock puts the job into via method `scheduleJob` with the job's next run time as the priority. Sherlock keeps checking the current system time, and pops the Priority Queue as required via method `consumeAndExecuteTasks`. For the actual detection, method `consumeAndExecuteTasks` executes a job that is due, which eventually goes to method `runDetection` under `DetectorService.java`. Method `runDetection` checks which detector the user wants to use, assign the corresponding DetectorAPIService instance, and calls the instance's `detectAnomalies` method. Method `detectAnomalies` does anomaly detection and returns anomaly points because job reports display only detected anomaly points. ### Understanding TimeSeries/Anomaly format used in Sherlock All current pipelines use `TimeSeries` and `Anomaly` classes defined in Egads heavily. To gain a better understanding of those formats, developers should read `TimeSeries.java/Anomaly.java` defined in the [Egads repository](https://github.com/yahoo/egads). ## Committers Jigar Patel, [jigsdevbox@gmail.com](mailto:jigsdevbox@gmail.com) Jeff Niu, [jeffniu22@gmail.com](mailto:jeffniu22@gmail.com) ## Contributors Josh Walters, [josh@joshwalters.com](mailto:josh@joshwalters.com) Stephan Stiefel, [Stephan3555](https://github.com/Stephan3555) Han Xu, [hanxu12](https://github.com/hanxu12) ## License Code licensed under the [GPL v3 License](https://www.gnu.org/licenses/quick-guide-gplv3.en.html). See LICENSE file for terms. 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