Search

Atlas exposes search over the metadata in two ways:

  • Basic Search
  • Advanced Search (DSL or Full-Text)

Basic search

The basic search allows you to query using typename of an entity, associated classification/tag and has support for filtering on the entity attribute(s) as well as the classification/tag attributes.

The entire query structure can be represented using the following JSON structure (called SearchParameters)

{
  "typeName": "hive_table",
  "excludeDeletedEntities": true,
  "classification" : "",
  "query": "",
  "limit": 25,
  "offset": 0,
  "entityFilters": {
   "attributeName": "name",
   "operator": "contains",
   "attributeValue": "testtable"
  },
  "tagFilters": null,
  "attributes": [""]
}

Field description

  • typeName: The type of entity to look for
  • excludeDeletedEntities: Should the search include deleted entities too (default: true)
  • classification: Only include entities with given Classification/tag
  • query: Any free text occurrence that the entity should have (generic/wildcard queries might be slow)
  • limit: Max number of results to fetch
  • offset: Starting offset of the result set (useful for pagination)
  • entityFilters: Entity Attribute filter(s)
  • tagFilters: Classification/tag Attribute filter(s)
  • attributes: Attributes to include in the search result (default: include any attribute present in the filter)

Attribute based filtering can be done on multiple attributes with AND/OR condition.

NOTE: The tagFilters and entityFilters field have same JSON structure.

Examples of filtering (for hive_table attributes)

  • Single attribute
   {
     "typeName": "hive_table",
     "excludeDeletedEntities": true,
     "classification" : "",
     "query": "",
     "limit": 50,
     "offset": 0,
     "entityFilters": {
        "attributeName": "name",
        "operator": "contains",
        "attributeValue": "testtable"
     },
     "tagFilters": null,
     "attributes": [""]
   }

  • Multi-attribute with OR
   {
     "typeName": "hive_table",
     "excludeDeletedEntities": true,
     "classification" : "",
     "query": "",
     "limit": 50,
     "offset": 0,
     "entityFilters": {
        "condition": "OR",
        "criterion": [
           {
              "attributeName": "name",
              "operator": "contains",
              "attributeValue": "testtable"
           },
           {
              "attributeName": "owner",
              "operator": "eq",
              "attributeValue": "admin"
           }
        ]
     },
     "tagFilters": null,
     "attributes": [""]
   }

  • Multi-attribute with AND
   {
     "typeName": "hive_table",
     "excludeDeletedEntities": true,
     "classification" : "",
     "query": "",
     "limit": 50,
     "offset": 0,
     "entityFilters": {
        "condition": "AND",
        "criterion": [
           {
              "attributeName": "name",
              "operator": "contains",
              "attributeValue": "testtable"
           },
           {
              "attributeName": "owner",
              "operator": "eq",
              "attributeValue": "admin"
           }
        ]
     },
     "tagFilters": null,
     "attributes": [""]
   }

Supported operators for filtering

  • LT (symbols: <, lt) works with Numeric, Date attributes
  • GT (symbols: >, gt) works with Numeric, Date attributes
  • LTE (symbols: <=, lte) works with Numeric, Date attributes
  • GTE (symbols: >=, gte) works with Numeric, Date attributes
  • EQ (symbols: eq, =) works with Numeric, Date, String attributes
  • NEQ (symbols: neq, !=) works with Numeric, Date, String attributes
  • LIKE (symbols: like, LIKE) works with String attributes
  • STARTS_WITH (symbols: startsWith, STARTSWITH) works with String attributes
  • ENDS_WITH (symbols: endsWith, ENDSWITH) works with String attributes
  • CONTAINS (symbols: contains, CONTAINS) works with String attributes

CURL Samples

    curl -sivk -g
    -u <user>:<password>
    -X POST
    -d '{
            "typeName": "hive_table",
            "excludeDeletedEntities": true,
            "classification" : "",
            "query": "",
            "limit": 50,
            "offset": 0,
            "entityFilters": {
               "condition": "AND",
               "criterion": [
                  {
                     "attributeName": "name",
                     "operator": "contains",
                     "attributeValue": "testtable"
                  },
                  {
                     "attributeName": "owner",
                     "operator": "eq",
                     "attributeValue": "admin"
                  }
               ]
            },
            "tagFilters": null,
            "attributes": [""]
          }'
    <protocol>://<atlas_host>:<atlas_port>/api/atlas/v2/search/basic

Advanced Search

Search DSL Grammar

The DSL exposes an SQL like query language for searching the metadata based on the type system. The grammar for the DSL is below.

queryWithPath: query ~ opt(WITHPATH)

query: querySrc ~ opt(loopExpression) ~ opt(groupByExpr) ~ opt(selectClause) ~ opt(orderby) ~ opt(limitOffset)

querySrc: rep1sep(singleQrySrc, opt(COMMA))

singleQrySrc = FROM ~ fromSrc ~ opt(WHERE) ~ opt(expr ^? notIdExpression) |
      WHERE ~ (expr ^? notIdExpression) |
      expr ^? notIdExpression |
      fromSrc ~ opt(WHERE) ~ opt(expr ^? notIdExpression)

fromSrc: identifier ~ AS ~ alias | identifier

groupByExpr = GROUPBY ~ (LPAREN ~> rep1sep(selectExpression, COMMA) <~ RPAREN)

orderby: ORDERBY ~ expr ~ opt (sortOrder)

limitOffset: LIMIT ~ lmt ~ opt (offset)

offset: OFFSET ~ offsetValue

sortOrder = ASC | DESC

loopExpression: LOOP ~ (LPAREN ~> query <~ RPAREN) ~ opt(intConstant <~ TIMES) ~ opt(AS ~> alias)

selectClause: SELECT ~ rep1sep(selectExpression, COMMA)

countClause =  COUNT ~ LPAREN ~ RPAREN

maxClause =  MAX ~ (LPAREN ~> expr <~ RPAREN)

minClause =   MIN ~ (LPAREN ~> expr <~ RPAREN)

sumClause =   SUM ~ (LPAREN ~> expr <~ RPAREN)

selectExpression:  expr ~ opt(AS ~> alias)

expr:  compE ~ opt(rep(exprRight))

exprRight: (AND | OR) ~ compE

compE:
      arithE ~ (LT | LTE | EQ | NEQ | GT | GTE) ~ arithE |
         arithE ~ (ISA | IS) ~ ident  |
         arithE ~ HAS ~ ident  |
         arithE | countClause | maxClause | minClause | sumClause

arithE: multiE ~ opt(rep(arithERight))

arithERight: (PLUS | MINUS) ~ multiE

multiE: atomE ~ opt(rep(multiERight))

multiERight: (STAR | DIV) ~ atomE

atomE: literal | identifier | LPAREN ~> expr <~ RPAREN

identifier: rep1sep(ident, DOT)

alias: ident | stringLit

literal: booleanConstant |
      intConstant  |
      longConstant  |
      floatConstant |
      doubleConstant  |
      stringLit

Grammar language: {noformat} opt(a) => a is optional ~ => a combinator. 'a ~ b' means a followed by b rep => zero or more rep1sep => one or more, separated by second arg. {noformat}

Language Notes:

  • A SingleQuery expression can be used to search for entities of a Trait or Class.
Entities can be filtered based on a 'Where Clause' and Entity Attributes can be retrieved based on a 'Select Clause'.
  • An Entity Graph can be traversed/joined by combining one or more SingleQueries.
  • An attempt is made to make the expressions look SQL like by accepting keywords "SELECT",
"FROM", and "WHERE"; but these are optional and users can simply think in terms of Entity Graph Traversals.
  • The transitive closure of an Entity relationship can be expressed via the Loop expression. A
Loop expression can be any traversal (recursively a query) that represents a Path that ends in an Entity of the same Type as the starting Entity.
  • The WithPath clause can be used with transitive closure queries to retrieve the Path that
connects the two related Entities. (We also provide a higher level interface for Closure Queries see scaladoc for 'org.apache.atlas.query.ClosureQuery')
  • GROUPBY is optional. Group by can be specified with aggregate methods like max, min, sum and count. When group by is specified aggregated results are returned based on the method specified in select clause. Select expression is mandatory with group by expression.
  • ORDERBY is optional. When order by clause is specified, case insensitive sorting is done based on the column specified.
For sorting in descending order specify 'DESC' after order by clause. If no order by is specified, then no default sorting is applied.
  • LIMIT is optional. It limits the maximum number of objects to be fetched starting from specified optional offset. If no offset is specified count starts from beginning.
  • There are couple of Predicate functions different from SQL:
* is or isacan be used to filter Entities that have a particular Trait. * has can be used to filter Entities that have a value for a particular Attribute.
  • Any identifiers or constants with special characters(space,$,",{,}) should be enclosed within backquote (`)
DSL Examples

For the model, Asset - attributes name, owner, description DB - supertype Asset - attributes clusterName, parameters, comment Column - extends Asset - attributes type, comment Table - supertype Asset - db, columns, parameters, comment Traits - PII, Log Data

DSL queries: * from DB

  • DB where name="Reporting" select name, owner
  • DB where name="Reporting" select name, owner orderby name
  • DB where name="Reporting" select name limit 10
  • DB where name="Reporting" select name, owner limit 10 offset 0
  • DB where name="Reporting" select name, owner orderby name limit 10 offset 5
  • DB where name="Reporting" select name, owner orderby name desc limit 10 offset 5
  • DB has name
  • DB is JdbcAccess
  • Column where Column isa PII
  • Table where name="sales_fact", columns
  • Table where name="sales_fact", columns as column select column.name, column.dataType, column.comment
  • DB groupby(owner) select owner, count()
  • DB groupby(owner) select owner, max(name)
  • DB groupby(owner) select owner, min(name)
  • from Person select count() as 'count', max(Person.age) as 'max', min(Person.age)
  • `Log Data`

Full-text Search

Atlas also exposes a lucene style full-text search capability.