neo4j functions: Interacting with a Neo4J database

The neo4j built-in functions allow you to interact with a Neo4J database.

info

Check out our tutorial on querying Neo4J.

Auth

Parameter	Type	Required	Default	Description
auth.scheme	String	Yes		Determines the type of auth credentials to use with Neo4J. Must be one of none, basic, kerberos, or bearer
auth.principal	String	No		Stores the username when auth.scheme is basic.
auth.credentials	String	No		Stores the password when auth.scheme is basic, the token when auth.scheme is bearer, and the ticket when auth.scheme is kerberos.
auth.realm	String	No		Stores the (optional) realm when auth.scheme is basic.

Errors

By default—and if raise_error is true—then an error returned will halt policy evaluation.

If raise_error is false, then the response object contains the error in an error key instead of its usual response.

{
  "error": ...
}

neo4j.query

The neo4j.query function allows you to make a query against a Neo4J database, returning multiple objects.

Parameter	Type	Required	Default	Description
uri	String	Yes		The URI of the database.
auth	Object	No		See Auth
cache	Bool	No	false	Cache the results of queries.
cache_duration	Integer	No	60	Duration (in seconds) to keep cached query results.
raise_error	Bool	No	true	See Errors
query	String	Yes		Cypher query to run against the Neo4J database.
parameters	Object	No		Parameters for substitution into the query.

Example usage

neo4j.query({
  "auth": {
    "scheme": "basic",
    "principal": "neo4j",
    "credentials": "letmein1!",
  },
  "uri": "http://localhost:7687",
  "query": "MATCH (n:Pet) WHERE n.age > $a RETURN n.name",
  "parameters": {"a": 3}
}) # => { "results": [ <object>, ... ] }

Utility helpers

Enterprise OPA comes with a helper method for using this builtin together with vault.send: neo4j.query.

This method is available in Enterprise OPA at data.system.eopa.utils.neo4j.v1.vault.

package example
import data.system.eopa.utils.neo4j.v1.vault as neo4j

example_1 := neo4j.query({"query": " ... ", "parameters": { ... }})
# => {"results": [ ... ]}

The utility method will lookup connection data from a map it expects to find in Vault, under the path secret/neo4j:

{
  "uri": "...",
  "scheme": "...",
  "credentials": "...",
  "principal": "...",
  "realm": "...",
}

If uri is not defined, it defaults to neo4j://localhost:7687. The scheme, credentials, principal, and realm keys behave as in the auth field of the neo4j.query() request object, see Auth.

To override the secret path within Vault, use:

package example
import data.system.eopa.utils.neo4j.v1.vault as neo4j

neo4j_query(req) := result {
  result := neo4j.query(req)
    with neo4j.override.secret_path as "secret/prod/eopa-neo4j"

example_2 := neo4j_query({"query": " ... ", "parameters": { ... }})
) # => {"results": [ ... ]}

If you need to override the Vault address or token, you can use this:

package example
import data.system.eopa.utils.vault.v1.env as vault
import data.system.eopa.utils.neo4j.v1.vault as neo4j

neo4j_query(req) := result {
  result := neo4j.query(req)
    with neo4j.override.secret_path as "secret/prod/eopa-neo4j"
    with vault.override.address as "localhost"
    with vault.override.token as "dev-token-2"
}

example_3 := neo4j_query({"query": " ... ", "parameters": { ... }})
) # => {"results": [ ... ]}