Manage GCP API Gateway IAM Policies

The gcp:apigateway/apiIamPolicy:ApiIamPolicy resource, part of the Pulumi GCP provider, manages IAM permissions for API Gateway APIs at three levels: entire policy replacement, role-level binding, or individual member grants. This guide focuses on three capabilities: authoritative policy replacement (ApiIamPolicy), role-level member binding (ApiIamBinding), and individual member grants (ApiIamMember).

These resources reference an existing API Gateway API. ApiIamPolicy cannot be used with ApiIamBinding or ApiIamMember, as they conflict over policy ownership. ApiIamBinding and ApiIamMember can coexist if they manage different roles. The examples are intentionally small. Combine them with your own API Gateway APIs and access requirements.

Replace the entire IAM policy for an API

When you need complete control over API access, you can set the entire IAM policy at once, replacing any existing permissions.

import * as pulumi from "@pulumi/pulumi";
import * as gcp from "@pulumi/gcp";

const admin = gcp.organizations.getIAMPolicy({
    bindings: [{
        role: "roles/apigateway.viewer",
        members: ["user:jane@example.com"],
    }],
});
const policy = new gcp.apigateway.ApiIamPolicy("policy", {
    project: api.project,
    api: api.apiId,
    policyData: admin.then(admin => admin.policyData),
});

import pulumi
import pulumi_gcp as gcp

admin = gcp.organizations.get_iam_policy(bindings=[{
    "role": "roles/apigateway.viewer",
    "members": ["user:jane@example.com"],
}])
policy = gcp.apigateway.ApiIamPolicy("policy",
    project=api["project"],
    api=api["apiId"],
    policy_data=admin.policy_data)

package main

import (
	"github.com/pulumi/pulumi-gcp/sdk/v9/go/gcp/apigateway"
	"github.com/pulumi/pulumi-gcp/sdk/v9/go/gcp/organizations"
	"github.com/pulumi/pulumi/sdk/v3/go/pulumi"
)

func main() {
	pulumi.Run(func(ctx *pulumi.Context) error {
		admin, err := organizations.LookupIAMPolicy(ctx, &organizations.LookupIAMPolicyArgs{
			Bindings: []organizations.GetIAMPolicyBinding{
				{
					Role: "roles/apigateway.viewer",
					Members: []string{
						"user:jane@example.com",
					},
				},
			},
		}, nil)
		if err != nil {
			return err
		}
		_, err = apigateway.NewApiIamPolicy(ctx, "policy", &apigateway.ApiIamPolicyArgs{
			Project:    pulumi.Any(api.Project),
			Api:        pulumi.Any(api.ApiId),
			PolicyData: pulumi.String(admin.PolicyData),
		})
		if err != nil {
			return err
		}
		return nil
	})
}

using System.Collections.Generic;
using System.Linq;
using Pulumi;
using Gcp = Pulumi.Gcp;

return await Deployment.RunAsync(() => 
{
    var admin = Gcp.Organizations.GetIAMPolicy.Invoke(new()
    {
        Bindings = new[]
        {
            new Gcp.Organizations.Inputs.GetIAMPolicyBindingInputArgs
            {
                Role = "roles/apigateway.viewer",
                Members = new[]
                {
                    "user:jane@example.com",
                },
            },
        },
    });

    var policy = new Gcp.ApiGateway.ApiIamPolicy("policy", new()
    {
        Project = api.Project,
        Api = api.ApiId,
        PolicyData = admin.Apply(getIAMPolicyResult => getIAMPolicyResult.PolicyData),
    });

});

package generated_program;

import com.pulumi.Context;
import com.pulumi.Pulumi;
import com.pulumi.core.Output;
import com.pulumi.gcp.organizations.OrganizationsFunctions;
import com.pulumi.gcp.organizations.inputs.GetIAMPolicyArgs;
import com.pulumi.gcp.apigateway.ApiIamPolicy;
import com.pulumi.gcp.apigateway.ApiIamPolicyArgs;
import java.util.List;
import java.util.ArrayList;
import java.util.Map;
import java.io.File;
import java.nio.file.Files;
import java.nio.file.Paths;

public class App {
    public static void main(String[] args) {
        Pulumi.run(App::stack);
    }

    public static void stack(Context ctx) {
        final var admin = OrganizationsFunctions.getIAMPolicy(GetIAMPolicyArgs.builder()
            .bindings(GetIAMPolicyBindingArgs.builder()
                .role("roles/apigateway.viewer")
                .members("user:jane@example.com")
                .build())
            .build());

        var policy = new ApiIamPolicy("policy", ApiIamPolicyArgs.builder()
            .project(api.project())
            .api(api.apiId())
            .policyData(admin.policyData())
            .build());

    }
}

resources:
  policy:
    type: gcp:apigateway:ApiIamPolicy
    properties:
      project: ${api.project}
      api: ${api.apiId}
      policyData: ${admin.policyData}
variables:
  admin:
    fn::invoke:
      function: gcp:organizations:getIAMPolicy
      arguments:
        bindings:
          - role: roles/apigateway.viewer
            members:
              - user:jane@example.com

The ApiIamPolicy resource is authoritative: it replaces the entire IAM policy on the API. The policyData property accepts output from getIAMPolicy, which defines roles and members in a bindings array. This approach gives you full control but overwrites any permissions not explicitly listed.

Grant a role to multiple members at once

Teams often need to grant the same role to several users or service accounts without affecting other roles.

import * as pulumi from "@pulumi/pulumi";
import * as gcp from "@pulumi/gcp";

const binding = new gcp.apigateway.ApiIamBinding("binding", {
    project: api.project,
    api: api.apiId,
    role: "roles/apigateway.viewer",
    members: ["user:jane@example.com"],
});

import pulumi
import pulumi_gcp as gcp

binding = gcp.apigateway.ApiIamBinding("binding",
    project=api["project"],
    api=api["apiId"],
    role="roles/apigateway.viewer",
    members=["user:jane@example.com"])

package main

import (
	"github.com/pulumi/pulumi-gcp/sdk/v9/go/gcp/apigateway"
	"github.com/pulumi/pulumi/sdk/v3/go/pulumi"
)

func main() {
	pulumi.Run(func(ctx *pulumi.Context) error {
		_, err := apigateway.NewApiIamBinding(ctx, "binding", &apigateway.ApiIamBindingArgs{
			Project: pulumi.Any(api.Project),
			Api:     pulumi.Any(api.ApiId),
			Role:    pulumi.String("roles/apigateway.viewer"),
			Members: pulumi.StringArray{
				pulumi.String("user:jane@example.com"),
			},
		})
		if err != nil {
			return err
		}
		return nil
	})
}

using System.Collections.Generic;
using System.Linq;
using Pulumi;
using Gcp = Pulumi.Gcp;

return await Deployment.RunAsync(() => 
{
    var binding = new Gcp.ApiGateway.ApiIamBinding("binding", new()
    {
        Project = api.Project,
        Api = api.ApiId,
        Role = "roles/apigateway.viewer",
        Members = new[]
        {
            "user:jane@example.com",
        },
    });

});

package generated_program;

import com.pulumi.Context;
import com.pulumi.Pulumi;
import com.pulumi.core.Output;
import com.pulumi.gcp.apigateway.ApiIamBinding;
import com.pulumi.gcp.apigateway.ApiIamBindingArgs;
import java.util.List;
import java.util.ArrayList;
import java.util.Map;
import java.io.File;
import java.nio.file.Files;
import java.nio.file.Paths;

public class App {
    public static void main(String[] args) {
        Pulumi.run(App::stack);
    }

    public static void stack(Context ctx) {
        var binding = new ApiIamBinding("binding", ApiIamBindingArgs.builder()
            .project(api.project())
            .api(api.apiId())
            .role("roles/apigateway.viewer")
            .members("user:jane@example.com")
            .build());

    }
}

resources:
  binding:
    type: gcp:apigateway:ApiIamBinding
    properties:
      project: ${api.project}
      api: ${api.apiId}
      role: roles/apigateway.viewer
      members:
        - user:jane@example.com

The ApiIamBinding resource is authoritative for a single role: it sets the complete member list for that role while preserving other roles on the API. The members property accepts an array of identities (users, service accounts, groups). If you later remove a member from this list, they lose access to this role.

Add a single member to a role incrementally

When you want to grant access to one user without disturbing existing permissions, you can add individual members.

import * as pulumi from "@pulumi/pulumi";
import * as gcp from "@pulumi/gcp";

const member = new gcp.apigateway.ApiIamMember("member", {
    project: api.project,
    api: api.apiId,
    role: "roles/apigateway.viewer",
    member: "user:jane@example.com",
});

import pulumi
import pulumi_gcp as gcp

member = gcp.apigateway.ApiIamMember("member",
    project=api["project"],
    api=api["apiId"],
    role="roles/apigateway.viewer",
    member="user:jane@example.com")

package main

import (
	"github.com/pulumi/pulumi-gcp/sdk/v9/go/gcp/apigateway"
	"github.com/pulumi/pulumi/sdk/v3/go/pulumi"
)

func main() {
	pulumi.Run(func(ctx *pulumi.Context) error {
		_, err := apigateway.NewApiIamMember(ctx, "member", &apigateway.ApiIamMemberArgs{
			Project: pulumi.Any(api.Project),
			Api:     pulumi.Any(api.ApiId),
			Role:    pulumi.String("roles/apigateway.viewer"),
			Member:  pulumi.String("user:jane@example.com"),
		})
		if err != nil {
			return err
		}
		return nil
	})
}

using System.Collections.Generic;
using System.Linq;
using Pulumi;
using Gcp = Pulumi.Gcp;

return await Deployment.RunAsync(() => 
{
    var member = new Gcp.ApiGateway.ApiIamMember("member", new()
    {
        Project = api.Project,
        Api = api.ApiId,
        Role = "roles/apigateway.viewer",
        Member = "user:jane@example.com",
    });

});

package generated_program;

import com.pulumi.Context;
import com.pulumi.Pulumi;
import com.pulumi.core.Output;
import com.pulumi.gcp.apigateway.ApiIamMember;
import com.pulumi.gcp.apigateway.ApiIamMemberArgs;
import java.util.List;
import java.util.ArrayList;
import java.util.Map;
import java.io.File;
import java.nio.file.Files;
import java.nio.file.Paths;

public class App {
    public static void main(String[] args) {
        Pulumi.run(App::stack);
    }

    public static void stack(Context ctx) {
        var member = new ApiIamMember("member", ApiIamMemberArgs.builder()
            .project(api.project())
            .api(api.apiId())
            .role("roles/apigateway.viewer")
            .member("user:jane@example.com")
            .build());

    }
}

resources:
  member:
    type: gcp:apigateway:ApiIamMember
    properties:
      project: ${api.project}
      api: ${api.apiId}
      role: roles/apigateway.viewer
      member: user:jane@example.com

The ApiIamMember resource is non-authoritative: it adds one member to a role without affecting other members who already have that role. The member property accepts a single identity. This approach is safest when multiple teams manage access to the same API, as it avoids accidentally removing permissions.

Beyond these examples

These snippets focus on specific IAM management approaches: authoritative vs non-authoritative IAM management, and policy-level, role-level, and member-level access control. They’re intentionally minimal rather than full access control systems.

The examples reference pre-existing infrastructure such as an API Gateway API resource (api.project and api.apiId). They focus on configuring IAM permissions rather than provisioning the API itself.

To keep things focused, common IAM patterns are omitted, including:

Conditional IAM bindings (condition blocks)
Custom IAM roles
Service account impersonation
Audit logging configuration

These omissions are intentional: the goal is to illustrate how each IAM resource type is wired, not provide drop-in access control modules. See the API Gateway ApiIamPolicy resource reference for all available configuration options.

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Frequently Asked Questions

Resource Selection & Conflicts

Can I mix ApiIamPolicy with ApiIamBinding or ApiIamMember?

No, gcp.apigateway.ApiIamPolicy cannot be used together with gcp.apigateway.ApiIamBinding or gcp.apigateway.ApiIamMember because they will conflict over the policy state.

Can I use ApiIamBinding and ApiIamMember together?

Yes, but only if they grant different roles. Using both for the same role will cause conflicts.

Which IAM resource should I use for my API Gateway API?

Choose based on your needs:

ApiIamPolicy - Authoritative, replaces the entire IAM policy
ApiIamBinding - Authoritative for a specific role, preserves other roles
ApiIamMember - Non-authoritative, adds a single member while preserving others

What's the difference between authoritative and non-authoritative IAM resources?

Authoritative resources (ApiIamPolicy, ApiIamBinding) replace existing permissions, while non-authoritative resources (ApiIamMember) add permissions without removing existing ones.

Configuration & Usage

How do I grant IAM access using ApiIamPolicy?

Use the gcp.organizations.getIAMPolicy data source to generate policyData, then pass it to the ApiIamPolicy resource’s policyData property.

What properties are immutable after creation?

The api and project properties cannot be changed after the resource is created.

Using a different cloud?

Explore security guides for other cloud providers:

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