Manage GCP Cloud Functions IAM Access

The gcp:cloudfunctions/functionIamMember:FunctionIamMember resource, part of the Pulumi GCP provider, manages IAM access for Cloud Functions by adding individual members to roles without affecting other role members. This guide focuses on three capabilities: adding single members to roles, managing complete role membership, and replacing entire IAM policies.

These IAM resources reference existing Cloud Functions and grant access to users, service accounts, or groups. The examples are intentionally small. Combine them with your own function definitions and identity management.

Grant a single user access to a function

Most access grants start by giving one user or service account permission to invoke or view a specific function.

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

const member = new gcp.cloudfunctions.FunctionIamMember("member", {
    project: _function.project,
    region: _function.region,
    cloudFunction: _function.name,
    role: "roles/viewer",
    member: "user:jane@example.com",
});

import pulumi
import pulumi_gcp as gcp

member = gcp.cloudfunctions.FunctionIamMember("member",
    project=function["project"],
    region=function["region"],
    cloud_function=function["name"],
    role="roles/viewer",
    member="user:jane@example.com")

package main

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

func main() {
	pulumi.Run(func(ctx *pulumi.Context) error {
		_, err := cloudfunctions.NewFunctionIamMember(ctx, "member", &cloudfunctions.FunctionIamMemberArgs{
			Project:       pulumi.Any(function.Project),
			Region:        pulumi.Any(function.Region),
			CloudFunction: pulumi.Any(function.Name),
			Role:          pulumi.String("roles/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.CloudFunctions.FunctionIamMember("member", new()
    {
        Project = function.Project,
        Region = function.Region,
        CloudFunction = function.Name,
        Role = "roles/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.cloudfunctions.FunctionIamMember;
import com.pulumi.gcp.cloudfunctions.FunctionIamMemberArgs;
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 FunctionIamMember("member", FunctionIamMemberArgs.builder()
            .project(function.project())
            .region(function.region())
            .cloudFunction(function.name())
            .role("roles/viewer")
            .member("user:jane@example.com")
            .build());

    }
}

resources:
  member:
    type: gcp:cloudfunctions:FunctionIamMember
    properties:
      project: ${function.project}
      region: ${function.region}
      cloudFunction: ${function.name}
      role: roles/viewer
      member: user:jane@example.com

FunctionIamMember adds a single member to a role without affecting other members who already have that role. The member property specifies the identity (user, service account, group, or special identifier like allUsers). The role property sets the permission level. This resource is non-authoritative, meaning multiple FunctionIamMember resources can grant the same role to different members without conflict.

Grant multiple users the same role

When a team needs the same level of access, FunctionIamBinding grants a role to multiple members at once.

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

const binding = new gcp.cloudfunctions.FunctionIamBinding("binding", {
    project: _function.project,
    region: _function.region,
    cloudFunction: _function.name,
    role: "roles/viewer",
    members: ["user:jane@example.com"],
});

import pulumi
import pulumi_gcp as gcp

binding = gcp.cloudfunctions.FunctionIamBinding("binding",
    project=function["project"],
    region=function["region"],
    cloud_function=function["name"],
    role="roles/viewer",
    members=["user:jane@example.com"])

package main

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

func main() {
	pulumi.Run(func(ctx *pulumi.Context) error {
		_, err := cloudfunctions.NewFunctionIamBinding(ctx, "binding", &cloudfunctions.FunctionIamBindingArgs{
			Project:       pulumi.Any(function.Project),
			Region:        pulumi.Any(function.Region),
			CloudFunction: pulumi.Any(function.Name),
			Role:          pulumi.String("roles/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.CloudFunctions.FunctionIamBinding("binding", new()
    {
        Project = function.Project,
        Region = function.Region,
        CloudFunction = function.Name,
        Role = "roles/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.cloudfunctions.FunctionIamBinding;
import com.pulumi.gcp.cloudfunctions.FunctionIamBindingArgs;
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 FunctionIamBinding("binding", FunctionIamBindingArgs.builder()
            .project(function.project())
            .region(function.region())
            .cloudFunction(function.name())
            .role("roles/viewer")
            .members("user:jane@example.com")
            .build());

    }
}

resources:
  binding:
    type: gcp:cloudfunctions:FunctionIamBinding
    properties:
      project: ${function.project}
      region: ${function.region}
      cloudFunction: ${function.name}
      role: roles/viewer
      members:
        - user:jane@example.com

FunctionIamBinding is authoritative for the specified role. The members array replaces any existing members for that role. If you later add another FunctionIamBinding for the same role, it will overwrite the first one. Use this when you want to manage all members for a role in one place, rather than adding them individually.

Replace the entire IAM policy for a function

Some deployments require complete control over all IAM bindings for a function.

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

const admin = gcp.organizations.getIAMPolicy({
    bindings: [{
        role: "roles/viewer",
        members: ["user:jane@example.com"],
    }],
});
const policy = new gcp.cloudfunctions.FunctionIamPolicy("policy", {
    project: _function.project,
    region: _function.region,
    cloudFunction: _function.name,
    policyData: admin.then(admin => admin.policyData),
});

import pulumi
import pulumi_gcp as gcp

admin = gcp.organizations.get_iam_policy(bindings=[{
    "role": "roles/viewer",
    "members": ["user:jane@example.com"],
}])
policy = gcp.cloudfunctions.FunctionIamPolicy("policy",
    project=function["project"],
    region=function["region"],
    cloud_function=function["name"],
    policy_data=admin.policy_data)

package main

import (
	"github.com/pulumi/pulumi-gcp/sdk/v9/go/gcp/cloudfunctions"
	"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/viewer",
					Members: []string{
						"user:jane@example.com",
					},
				},
			},
		}, nil)
		if err != nil {
			return err
		}
		_, err = cloudfunctions.NewFunctionIamPolicy(ctx, "policy", &cloudfunctions.FunctionIamPolicyArgs{
			Project:       pulumi.Any(function.Project),
			Region:        pulumi.Any(function.Region),
			CloudFunction: pulumi.Any(function.Name),
			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/viewer",
                Members = new[]
                {
                    "user:jane@example.com",
                },
            },
        },
    });

    var policy = new Gcp.CloudFunctions.FunctionIamPolicy("policy", new()
    {
        Project = function.Project,
        Region = function.Region,
        CloudFunction = function.Name,
        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.cloudfunctions.FunctionIamPolicy;
import com.pulumi.gcp.cloudfunctions.FunctionIamPolicyArgs;
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/viewer")
                .members("user:jane@example.com")
                .build())
            .build());

        var policy = new FunctionIamPolicy("policy", FunctionIamPolicyArgs.builder()
            .project(function.project())
            .region(function.region())
            .cloudFunction(function.name())
            .policyData(admin.policyData())
            .build());

    }
}

resources:
  policy:
    type: gcp:cloudfunctions:FunctionIamPolicy
    properties:
      project: ${function.project}
      region: ${function.region}
      cloudFunction: ${function.name}
      policyData: ${admin.policyData}
variables:
  admin:
    fn::invoke:
      function: gcp:organizations:getIAMPolicy
      arguments:
        bindings:
          - role: roles/viewer
            members:
              - user:jane@example.com

FunctionIamPolicy sets the entire IAM policy, replacing any existing configuration. The policyData comes from the getIAMPolicy data source, which defines bindings (role and member pairs). This resource is authoritative for the entire policy. It cannot be used alongside FunctionIamBinding or FunctionIamMember, as they will conflict over policy ownership.

Beyond these examples

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

The examples reference pre-existing infrastructure such as Cloud Functions that need IAM configuration, and user accounts, service accounts, or groups to grant access to. They focus on configuring IAM bindings rather than provisioning the functions themselves.

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

Conditional IAM bindings (condition property)
Custom role definitions
Cross-project or organization-level policies
Federated identity configuration details

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 FunctionIamMember resource reference for all available configuration options.

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Frequently Asked Questions

Resource Selection & Compatibility

What's the difference between FunctionIamPolicy, FunctionIamBinding, and FunctionIamMember?

FunctionIamPolicy is authoritative and replaces the entire IAM policy. FunctionIamBinding is authoritative for a specific role, preserving other roles. FunctionIamMember is non-authoritative and adds a single member to a role without affecting other members.

Can I use FunctionIamPolicy with FunctionIamBinding or FunctionIamMember?

No, FunctionIamPolicy cannot be used with FunctionIamBinding or FunctionIamMember because they will conflict over the policy. Choose one approach: use FunctionIamPolicy alone for full control, or use FunctionIamBinding/FunctionIamMember for incremental changes.

Can I use FunctionIamBinding and FunctionIamMember together?

Yes, but only if they don’t grant privileges to the same role. Using both resources for the same role will cause conflicts.

Configuration & Formats

What member identity formats are supported?

You can use: allUsers, allAuthenticatedUsers, user:{email}, serviceAccount:{email}, group:{email}, domain:{domain}, projectOwner:projectid, projectEditor:projectid, projectViewer:projectid, and federated identities (e.g., principal://iam.googleapis.com/...).

How do I specify custom roles?

Custom roles must use the full path format: [projects|organizations]/{parent-name}/roles/{role-name}. For example, projects/my-project/roles/my-custom-role or organizations/my-org/roles/my-custom-role.

What properties can't be changed after creation?

All input properties are immutable: cloudFunction, member, project, region, role, and condition. Changing any of these requires recreating the resource.

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