Cosmos DB data source for a resolver

APPLIES TO: Developer | Basic | Basic v2 | Standard | Standard v2 | Premium | Premium v2

The cosmosdb-data-source resolver policy resolves data for an object type and field in a GraphQL schema by using a Cosmos DB data source. The schema must be imported to API Management as a GraphQL API.

Use the policy to configure a single query request, read request, delete request, or write request and an optional response from the Cosmos DB data source.

Policy statement

<cosmosdb-data-source> 
    <!-- Required information that specifies connection to Cosmos DB -->
    <connection-info> 
        <connection-string use-managed-identity="true | false"> 
            AccountEndpoint=...;[AccountKey=...;]
        </connection-string> 
        <database-name>Cosmos DB database name</database-name> 
        <container-name>Name of container in Cosmos DB database</container-name>     
    </connection-info>

    <!-- Settings to query using a SQL statement and optional query parameters -->
    <query-request enable-low-precision-order-by="true | false"> 
        <sql-statement> 
            SQL statement 
        </sql-statement> 
        <parameters> 
            <parameter name="Query parameter name in @ notation"> 
                "Query parameter value or expression"
            </parameter>
            <!-- if there are multiple parameters, then add additional parameter elements --> 
        </parameters> 
        <partition-key data-type="string | number | bool | none | null" template="liquid" > 
            "Container partition key" 
        </partition-key> 
        <paging> 
            <max-item-count template="liquid" > 
                Maximum number of items returned by query
            </max-item-count> 
            <continuation-token template="liquid"> 
                Continuation token for paging 
            </continuation-token> 
        </paging>
    </query-request>
    
    <!-- Settings to read item by item ID and optional partition key --> 
    <read-request> 
        <id template="liquid" >
            "Item ID in container"
        </id> 
        <partition-key data-type="string | number | bool | none | null" template="liquid" > 
            "Container partition key" 
        </partition-key>  
    </read-request> 
    
    <!-- Settings to delete item by ID and optional partition key --> 
    <delete-request consistency-level="bounded-staleness | consistent-prefix | eventual | session | strong" pre-trigger="myPreTrigger" post-trigger="myPostTrigger">
        <etag type="entity tag type" template="liquid" > 
            "System-generated entity tag" 
        </etag> 
        <id template="liquid">
            "Item ID in container"
        </id> 
        <partition-key data-type="string | number | bool | none | null" template="liquid"> 
            "Container partition key" 
        </partition-key> 
    </delete-request> 
    
    <!-- Settings to write item -->
    <write-request type="insert | replace | upsert" consistency-level="bounded-staleness | consistent-prefix | eventual | session | strong" pre-trigger="myPreTrigger" post-trigger="myPostTrigger">
        <id template="liquid">
            "Item ID in container"
        </id>
         <partition-key data-type="string | number | bool | none | null" template="liquid"> 
            "Container partition key"
        </partition-key>      
        <etag type="match | no-match" template="liquid" > 
            "System-generated entity tag" 
        </etag>
        <set-body template="liquid" >...set-body policy configuration...</set-body> 
    </write-request>
    
    <response> 
        <set-body>...set-body policy configuration...</set-body> 
        <publish-event>...publish-event policy configuration...</publish-event>
    </response>
    
</cosmosdb-data-source> 

Elements

connection-info elements

connection-string attributes

query-request attributes

query-request elements

parameter attributes

paging elements

max-item-count attribute

continuation-token attribute

read-request elements

delete-request attributes

delete-request elements

write-request attributes

write-request elements

response elements

partition-key attributes

etag attribute

Usage

• Policy scopes: GraphQL resolver
• Gateways: classic, v2

Usage notes

• To configure and manage a resolver with this policy, see Configure a GraphQL resolver.
• This policy is invoked only when resolving a single field in a matching operation type in the schema.

Configure managed identity integration with Cosmos DB

You can configure an API Management system-assigned managed identity to access a Cosmos DB account, instead of providing an account key in the connection string.

Follow these steps to use the Azure CLI to configure the managed identity.

Prerequisites

• Enable a system-assigned managed identity in your API Management instance. In the portal, note the object (principal) ID of the managed identity.

• • Use the Bash environment in Azure Cloud Shell. For more information, see Quickstart for Bash in Azure Cloud Shell.

    

  • If you prefer to run CLI reference commands locally, install the Azure CLI. If you're running on Windows or macOS, consider running Azure CLI in a Docker container. For more information, see How to run the Azure CLI in a Docker container.

    • If you're using a local installation, sign in to the Azure CLI by using the az login command. To finish the authentication process, follow the steps displayed in your terminal. For other sign-in options, see Sign in with the Azure CLI.

    • When you're prompted, install the Azure CLI extension on first use. For more information about extensions, see Use extensions with the Azure CLI.

    • Run az version to find the version and dependent libraries that are installed. To upgrade to the latest version, run az upgrade.

Azure CLI script to configure the managed identity

# Set variables

# Variable for Azure Cosmos DB account name
cosmosName="<MY-COSMOS-DB-ACCOUNT>"

# Variable for resource group name
resourceGroupName="<MY-RESOURCE-GROUP>"

# Variable for subscription
resourceGroupName="<MY-SUBSCRIPTION-NAME>"

# Set principal variable to the value from Managed identities page of API Management instance in Azure portal
principal="<MY-APIM-MANAGED-ID-PRINCIPAL-ID>"

# Get the scope value of Cosmos DB account
 
scope=$(
    az cosmosdb show \
        --resource-group $resourceGroupName \
        --name $cosmosName \
        --subscription $subscriptionName \
        --query id \
        --output tsv
)

# List the built-in Cosmos DB roles
# Currently, the roles aren't visible in the portal

az cosmosdb sql role definition list \
    --resource-group $resourceGroupName \
    --account-name $cosmosName \
    --subscription $subscriptionName \

# Take note of the role you want to assign, such as "Cosmos DB Built-in Data Contributor" in this example

# Assign desired Cosmos DB role to managed identity

az cosmosdb sql role assignment create \
    --resource-group $resourceGroupName \
    --account-name $cosmosName \
    --subscription $subscriptionName \
    --role-definition-name "Cosmos DB Built-in Data Contributor" \
    --principal-id $principal \
    --scope $scope    

Examples

Cosmos DB query request

The following example resolves a GraphQL query using a SQL query to a Cosmos DB container.

<cosmosdb-data-source>
    <connection-info>
        <connection-string>
            AccountEndpoint=https://contoso-cosmosdb.
documents.azure.com:443/;AccountKey=CONTOSOKEY;
        </connection-string>
        <database-name>myDatabase</database-name>
        <container-name>myContainer</container-name>
    </connection-info>
    <query-request>
        <sql-statement>SELECT * FROM c </sql-statement>
    </query-request>
</cosmosdb-data-source>

Cosmos DB read request

The following example resolves a GraphQL query using a point read request to a Cosmos DB container. The connection to the Cosmos DB account uses the API Management instance's system-assigned managed identity. The identity must be configured to access the Cosmos DB container.

The id and partition-key used for the read request are passed as query parameters and accessed using the context.GraphQL.Arguments["id"] context variable.

<cosmosdb-data-source>
    <connection-info>
        <connection-string use-managed-identity="true">
            AccountEndpoint=https://contoso-cosmosdb.
documents.azure.com:443/;
        </connection-string>
        <database-name>myDatabase</database-name>
        <container-name>myContainer</container-name>
    </connection-info>
    <read-request>
        <id>
            @(context.GraphQL.Arguments["id"].ToString())
        </id>
        <partition-key>
            @(context.GraphQL.Arguments["id"].ToString())
    <read-request>
</cosmosdb-data-source>

Cosmos DB delete request

The following example resolves a GraphQL mutation by a delete request to a Cosmos DB container. The id and partition-key used for the delete request are passed as query parameters and accessed using the context.GraphQL.Arguments["id"] context variable.

<cosmosdb-data-source>
    <connection-info>
        <connection-string>
            AccountEndpoint=https://contoso-cosmosdb.
documents.azure.com:443/;AccountKey=CONTOSOKEY;
        </connection-string>
        <database-name>myDatabase</database-name>
        <container-name>myContainer</container-name>
    </connection-info>
    <delete-request>
        <id>
            @(context.GraphQL.Arguments["id"].ToString())
        </id>
        <partition-key>
            @(context.GraphQL.Arguments["id"].ToString())
        </partition-key>
    </delete-request>
</cosmosdb-data-source>

Cosmos DB write request

The following example resolves a GraphQL mutation by an upsert request to a Cosmos DB container. The connection to the Cosmos DB account uses the API Management instance's system-assigned managed identity. The identity must be configured to access the Cosmos DB container.

The partition-key used for the write request is passed as a query parameter and accessed using the context.GraphQL.Arguments["id"] context variable. The upsert request has a pre-trigger operation named "validateInput". The request body is mapped using a liquid template.

<cosmosdb-data-source>
    <connection-info>
        <connection-string use-managed-identity="true">
            AccountEndpoint=https://contoso-cosmosdb.
documents.azure.com:443/;
        </connection-string>
        <database-name>myDatabase</database-name>
        <container-name>myContainer</container-name>
    </connection-info>
    <write-request type="upsert" pre-trigger="validateInput">
        <partition-key>
            @(context.GraphQL.Arguments["id"].ToString())
        </partition-key>
        <set-body template="liquid">
            {"id" : "{{body.arguments.id}}" ,
            "firstName" : "{{body.arguments.firstName}}",
            "intField" : {{body.arguments.intField}} ,
            "floatField" : {{body.arguments.floatField}} ,
            "boolField" : {{body.arguments.boolField}}}
        </set-body>
    </write-request>
</cosmosdb-data-source>

Construct parameter input for Cosmos DB query

The following examples show ways to construct Cosmos DB parameterized queries using policy expressions. Choose a method based on the form of your parameter input.

The examples are based on the following sample GraphQL schema, and generate the corresponding Cosmos DB parameterized query.

Example GraphQL schema

input personInput {
  id: String!
  firstName: String
}

type Query {
  personsStringParam(stringInput: String): personsConnection
  personsPersonParam(input: personInput): personsConnection
}

Example Cosmos DB query

{
    "query": "query { 
        personsPersonParam(input: { id: \"3\" } { 
        items { id firstName lastName } 
        } 
    }"
}    

Pass JSON object (JObject) from expression

Example policy

[...]
<query-request>
    <sql-statement>SELECT * FROM c where c.familyId [email protected]</sql-statement>
    <parameters>
        <parameter name="@param">@(context.GraphQL.Arguments["input"])</parameter>
    </parameters>
    </query-request>
[...]

Pass .NET input type (string, int, decimal, bool) from expression

Example policy

[...]
<query-request>
    <sql-statement>SELECT * FROM c where c.familyId =@param</sql-statement>
    <parameters>
        <parameter name="@param">@($"start.{context.GraphQL.Arguments["stringInput"]}")</parameter>
    </parameters>
</query-request>
[...]

Pass JSON value (JValue) from expression

Example policy

[...]
<query-request>
    <sql-statement>SELECT * FROM c where c.familyId =@param</sql-statement>
    <parameters>
        <parameter name="@param">@(context.GraphQL.Arguments["stringInput"])</parameter>
    </parameters>
</query-request>
[...]

Related policies

• GraphQL resolvers

Related content

For more information about working with policies, see:

• Tutorial: Transform and protect your API
• Policy reference for a full list of policy statements and their settings
• Policy expressions
• Set or edit policies
• Reuse policy configurations
• Policy snippets repo
• Author policies using Microsoft Copilot in Azure