/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.pulsar.functions.worker.rest.api;

import com.google.protobuf.ByteString;
import lombok.extern.slf4j.Slf4j;
import org.apache.pulsar.broker.authentication.AuthenticationDataHttps;
import org.apache.pulsar.broker.authentication.AuthenticationDataSource;
import org.apache.pulsar.client.admin.PulsarAdminException;
import org.apache.pulsar.common.functions.FunctionConfig;
import org.apache.pulsar.common.functions.UpdateOptions;
import org.apache.pulsar.common.functions.Utils;
import org.apache.pulsar.common.policies.data.ExceptionInformation;
import org.apache.pulsar.common.policies.data.FunctionStatus;
import org.apache.pulsar.functions.auth.FunctionAuthData;
import org.apache.pulsar.functions.instance.InstanceUtils;
import org.apache.pulsar.functions.proto.Function;
import org.apache.pulsar.functions.proto.InstanceCommunication;
import org.apache.pulsar.functions.utils.ComponentTypeUtils;
import org.apache.pulsar.functions.utils.FunctionCommon;
import org.apache.pulsar.functions.utils.FunctionConfigUtils;
import org.apache.pulsar.functions.worker.FunctionMetaDataManager;
import org.apache.pulsar.functions.worker.WorkerService;
import org.apache.pulsar.functions.worker.WorkerUtils;
import org.apache.pulsar.functions.worker.rest.RestException;
import org.glassfish.jersey.media.multipart.FormDataContentDisposition;

import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.Response;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.util.Collection;
import java.util.LinkedList;
import java.util.List;
import java.util.Optional;
import java.util.function.Supplier;

import static org.apache.commons.lang3.StringUtils.isBlank;
import static org.apache.commons.lang3.StringUtils.isNotBlank;
import static org.apache.pulsar.functions.auth.FunctionAuthUtils.getFunctionAuthData;
import static org.apache.pulsar.functions.worker.WorkerUtils.isFunctionCodeBuiltin;
import static org.apache.pulsar.functions.worker.rest.RestUtils.throwUnavailableException;

@Slf4j
public class FunctionsImpl extends ComponentImpl {

    public FunctionsImpl(Supplier<WorkerService> workerServiceSupplier) {
        super(workerServiceSupplier, Function.FunctionDetails.ComponentType.FUNCTION);
    }

    public void registerFunction(final String tenant,
                                 final String namespace,
                                 final String functionName,
                                 final InputStream uploadedInputStream,
                                 final FormDataContentDisposition fileDetail,
                                 final String functionPkgUrl,
                                 final FunctionConfig functionConfig,
                                 final String clientRole,
                                 AuthenticationDataHttps clientAuthenticationDataHttps) {

        if (!isWorkerServiceAvailable()) {
            throwUnavailableException();
        }

        if (tenant == null) {
            throw new RestException(Response.Status.BAD_REQUEST, "Tenant is not provided");
        }
        if (namespace == null) {
            throw new RestException(Response.Status.BAD_REQUEST, "Namespace is not provided");
        }
        if (functionName == null) {
            throw new RestException(Response.Status.BAD_REQUEST, "Function name is not provided");
        }
        if (functionConfig == null) {
            throw new RestException(Response.Status.BAD_REQUEST, "Function config is not provided");
        }

        try {
            if (!isAuthorizedRole(tenant, namespace, clientRole, clientAuthenticationDataHttps)) {
                log.error("{}/{}/{} Client [{}] is not authorized to register {}", tenant, namespace,
                        functionName, clientRole, ComponentTypeUtils.toString(componentType));
                throw new RestException(Response.Status.UNAUTHORIZED, "client is not authorize to perform operation");
            }
        } catch (PulsarAdminException e) {
            log.error("{}/{}/{} Failed to authorize [{}]", tenant, namespace, functionName, e);
            throw new RestException(Response.Status.INTERNAL_SERVER_ERROR, e.getMessage());
        }

        try {
            // Check tenant exists
            worker().getBrokerAdmin().tenants().getTenantInfo(tenant);

            String qualifiedNamespace = tenant + "/" + namespace;
            List<String> namespaces = worker().getBrokerAdmin().namespaces().getNamespaces(tenant);
            if (namespaces != null && !namespaces.contains(qualifiedNamespace)) {
                String qualifiedNamespaceWithCluster = String.format("%s/%s/%s", tenant,
                        worker().getWorkerConfig().getPulsarFunctionsCluster(), namespace);
                if (namespaces != null && !namespaces.contains(qualifiedNamespaceWithCluster)) {
                    log.error("{}/{}/{} Namespace {} does not exist", tenant, namespace, functionName, namespace);
                    throw new RestException(Response.Status.BAD_REQUEST, "Namespace does not exist");
                }
            }
        } catch (PulsarAdminException.NotAuthorizedException e) {
            log.error("{}/{}/{} Client [{}] is not authorized to operate {} on tenant", tenant, namespace,
                    functionName, clientRole, ComponentTypeUtils.toString(componentType));
            throw new RestException(Response.Status.UNAUTHORIZED, "client is not authorize to perform operation");
        } catch (PulsarAdminException.NotFoundException e) {
            log.error("{}/{}/{} Tenant {} does not exist", tenant, namespace, functionName, tenant);
            throw new RestException(Response.Status.BAD_REQUEST, "Tenant does not exist");
        } catch (PulsarAdminException e) {
            log.error("{}/{}/{} Issues getting tenant data", tenant, namespace, functionName, e);
            throw new RestException(Response.Status.INTERNAL_SERVER_ERROR, e.getMessage());
        }

        FunctionMetaDataManager functionMetaDataManager = worker().getFunctionMetaDataManager();

        if (functionMetaDataManager.containsFunction(tenant, namespace, functionName)) {
            log.error("{} {}/{}/{} already exists", ComponentTypeUtils.toString(componentType), tenant, namespace, functionName);
            throw new RestException(Response.Status.BAD_REQUEST, String.format("%s %s already exists", ComponentTypeUtils.toString(componentType), functionName));
        }

        Function.FunctionDetails functionDetails = null;
        boolean isPkgUrlProvided = isNotBlank(functionPkgUrl);
        File componentPackageFile = null;
        try {

            // validate parameters
            try {
                if (isPkgUrlProvided) {

                    if (!Utils.isFunctionPackageUrlSupported(functionPkgUrl)) {
                        throw new IllegalArgumentException("Function Package url is not valid. supported url (http/https/file)");
                    }
                    try {
                        componentPackageFile = FunctionCommon.extractFileFromPkgURL(functionPkgUrl);
                    } catch (Exception e) {
                        throw new IllegalArgumentException(String.format("Encountered error \"%s\" when getting %s package from %s", e.getMessage(), ComponentTypeUtils.toString(componentType), functionPkgUrl));
                    }
                    functionDetails = validateUpdateRequestParams(tenant, namespace, functionName,
                            functionConfig, componentPackageFile);
                } else {
                    if (uploadedInputStream != null) {
                        componentPackageFile = WorkerUtils.dumpToTmpFile(uploadedInputStream);
                    }
                    functionDetails = validateUpdateRequestParams(tenant, namespace, functionName,
                            functionConfig, componentPackageFile);
                    if (!isFunctionCodeBuiltin(functionDetails) && (componentPackageFile == null || fileDetail == null)) {
                        throw new IllegalArgumentException(ComponentTypeUtils.toString(componentType) + " Package is not provided");
                    }
                }
            } catch (Exception e) {
                log.error("Invalid register {} request @ /{}/{}/{}", ComponentTypeUtils.toString(componentType), tenant, namespace, functionName, e);
                throw new RestException(Response.Status.BAD_REQUEST, e.getMessage());
            }

            try {
                worker().getFunctionRuntimeManager().getRuntimeFactory().doAdmissionChecks(functionDetails);
            } catch (Exception e) {
                log.error("{} {}/{}/{} cannot be admitted by the runtime factory", ComponentTypeUtils.toString(componentType), tenant, namespace, functionName);
                throw new RestException(Response.Status.BAD_REQUEST, String.format("%s %s cannot be admitted:- %s", ComponentTypeUtils.toString(componentType), functionName, e.getMessage()));
            }

            // function state
            Function.FunctionMetaData.Builder functionMetaDataBuilder = Function.FunctionMetaData.newBuilder()
                    .setFunctionDetails(functionDetails)
                    .setCreateTime(System.currentTimeMillis())
                    .setVersion(0);

            // cache auth if need
            if (worker().getWorkerConfig().isAuthenticationEnabled()) {

                if (clientAuthenticationDataHttps != null) {
                    try {
                        Optional<FunctionAuthData> functionAuthData = worker().getFunctionRuntimeManager()
                                .getRuntimeFactory()
                                .getAuthProvider()
                                .cacheAuthData(tenant, namespace, functionName, clientAuthenticationDataHttps);

                        if (functionAuthData.isPresent()) {
                            functionMetaDataBuilder.setFunctionAuthSpec(
                                    Function.FunctionAuthenticationSpec.newBuilder()
                                            .setData(ByteString.copyFrom(functionAuthData.get().getData()))
                                            .build());
                        }
                    } catch (Exception e) {
                        log.error("Error caching authentication data for {} {}/{}/{}", ComponentTypeUtils.toString(componentType), tenant, namespace, functionName, e);


                        throw new RestException(Response.Status.INTERNAL_SERVER_ERROR, String.format("Error caching authentication data for %s %s:- %s", ComponentTypeUtils.toString(componentType), functionName, e.getMessage()));
                    }
                }
            }

            Function.PackageLocationMetaData.Builder packageLocationMetaDataBuilder;
            try {
                packageLocationMetaDataBuilder = getFunctionPackageLocation(functionMetaDataBuilder.build(),
                        functionPkgUrl, fileDetail, componentPackageFile);
            } catch (Exception e) {
                log.error("Failed process {} {}/{}/{} package: ", ComponentTypeUtils.toString(componentType), tenant, namespace, functionName, e);
                throw new RestException(Response.Status.INTERNAL_SERVER_ERROR, e.getMessage());
            }

            functionMetaDataBuilder.setPackageLocation(packageLocationMetaDataBuilder);
            updateRequest(functionMetaDataBuilder.build());
        } finally {

            if (!(functionPkgUrl != null && functionPkgUrl.startsWith(Utils.FILE))
                    && componentPackageFile != null && componentPackageFile.exists()) {
                componentPackageFile.delete();
            }
        }
    }

    public void updateFunction(final String tenant,
                               final String namespace,
                               final String functionName,
                               final InputStream uploadedInputStream,
                               final FormDataContentDisposition fileDetail,
                               final String functionPkgUrl,
                               final FunctionConfig functionConfig,
                               final String clientRole,
                               AuthenticationDataHttps clientAuthenticationDataHttps,
                               UpdateOptions updateOptions) {

        if (!isWorkerServiceAvailable()) {
            throwUnavailableException();
        }

        if (tenant == null) {
            throw new RestException(Response.Status.BAD_REQUEST, "Tenant is not provided");
        }
        if (namespace == null) {
            throw new RestException(Response.Status.BAD_REQUEST, "Namespace is not provided");
        }
        if (functionName == null) {
            throw new RestException(Response.Status.BAD_REQUEST, "Function name is not provided");
        }
        if (functionConfig == null) {
            throw new RestException(Response.Status.BAD_REQUEST, "Function config is not provided");
        }

        try {
            if (!isAuthorizedRole(tenant, namespace, clientRole, clientAuthenticationDataHttps)) {
                log.error("{}/{}/{} Client [{}] is not authorized to update {}", tenant, namespace,
                        functionName, clientRole, ComponentTypeUtils.toString(componentType));
                throw new RestException(Response.Status.UNAUTHORIZED, "client is not authorize to perform operation");

            }
        } catch (PulsarAdminException e) {
            log.error("{}/{}/{} Failed to authorize [{}]", tenant, namespace, functionName, e);
            throw new RestException(Response.Status.INTERNAL_SERVER_ERROR, e.getMessage());
        }

        FunctionMetaDataManager functionMetaDataManager = worker().getFunctionMetaDataManager();

        if (!functionMetaDataManager.containsFunction(tenant, namespace, functionName)) {
            throw new RestException(Response.Status.BAD_REQUEST, String.format("%s %s doesn't exist", ComponentTypeUtils.toString(componentType), functionName));
        }

        Function.FunctionMetaData existingComponent = functionMetaDataManager.getFunctionMetaData(tenant, namespace, functionName);

        if (!InstanceUtils.calculateSubjectType(existingComponent.getFunctionDetails()).equals(componentType)) {
            log.error("{}/{}/{} is not a {}", tenant, namespace, functionName, ComponentTypeUtils.toString(componentType));
            throw new RestException(Response.Status.NOT_FOUND, String.format("%s %s doesn't exist", ComponentTypeUtils.toString(componentType), functionName));
        }

        FunctionConfig existingFunctionConfig = FunctionConfigUtils.convertFromDetails(existingComponent.getFunctionDetails());
        // The rest end points take precedence over whatever is there in function config
        functionConfig.setTenant(tenant);
        functionConfig.setNamespace(namespace);
        functionConfig.setName(functionName);
        FunctionConfig mergedConfig;
        try {
            mergedConfig = FunctionConfigUtils.validateUpdate(existingFunctionConfig, functionConfig);
        } catch (Exception e) {
            throw new RestException(Response.Status.BAD_REQUEST, e.getMessage());
        }

        if (existingFunctionConfig.equals(mergedConfig) && isBlank(functionPkgUrl) && uploadedInputStream == null) {
            log.error("{}/{}/{} Update contains no changes", tenant, namespace, functionName);
            throw new RestException(Response.Status.BAD_REQUEST, "Update contains no change");
        }

        Function.FunctionDetails functionDetails = null;
        File componentPackageFile = null;
        try {

            // validate parameters
            try {
                if (isNotBlank(functionPkgUrl)) {
                    try {
                        componentPackageFile = FunctionCommon.extractFileFromPkgURL(functionPkgUrl);
                    } catch (Exception e) {
                        throw new IllegalArgumentException(String.format("Encountered error \"%s\" when getting %s package from %s", e.getMessage(), ComponentTypeUtils.toString(componentType), functionPkgUrl));
                    }
                    functionDetails = validateUpdateRequestParams(tenant, namespace, functionName,
                            mergedConfig, componentPackageFile);

                } else if (existingComponent.getPackageLocation().getPackagePath().startsWith(Utils.FILE)
                        || existingComponent.getPackageLocation().getPackagePath().startsWith(Utils.HTTP)) {
                    try {
                        componentPackageFile = FunctionCommon.extractFileFromPkgURL(existingComponent.getPackageLocation().getPackagePath());
                    } catch (Exception e) {
                        throw new IllegalArgumentException(String.format("Encountered error \"%s\" when getting %s package from %s", e.getMessage(), ComponentTypeUtils.toString(componentType), functionPkgUrl));
                    }
                    functionDetails = validateUpdateRequestParams(tenant, namespace, functionName,
                            mergedConfig, componentPackageFile);
                } else if (uploadedInputStream != null) {

                    componentPackageFile = WorkerUtils.dumpToTmpFile(uploadedInputStream);
                    functionDetails = validateUpdateRequestParams(tenant, namespace, functionName,
                            mergedConfig, componentPackageFile);

                } else if (existingComponent.getPackageLocation().getPackagePath().startsWith(Utils.BUILTIN)) {
                    functionDetails = validateUpdateRequestParams(tenant, namespace, functionName,
                            mergedConfig, componentPackageFile);
                    if (!isFunctionCodeBuiltin(functionDetails) && (componentPackageFile == null || fileDetail == null)) {
                        throw new IllegalArgumentException(ComponentTypeUtils.toString(componentType) + " Package is not provided");
                    }
                } else {

                    componentPackageFile = FunctionCommon.createPkgTempFile();
                    componentPackageFile.deleteOnExit();
                    WorkerUtils.downloadFromBookkeeper(worker().getDlogNamespace(), componentPackageFile, existingComponent.getPackageLocation().getPackagePath());

                    functionDetails = validateUpdateRequestParams(tenant, namespace, functionName,
                            mergedConfig, componentPackageFile);
                }
            } catch (Exception e) {
                log.error("Invalid update {} request @ /{}/{}/{}", ComponentTypeUtils.toString(componentType), tenant, namespace, functionName, e);
                throw new RestException(Response.Status.BAD_REQUEST, e.getMessage());
            }

            try {
                worker().getFunctionRuntimeManager().getRuntimeFactory().doAdmissionChecks(functionDetails);
            } catch (Exception e) {
                log.error("Updated {} {}/{}/{} cannot be submitted to runtime factory", ComponentTypeUtils.toString(componentType), tenant, namespace, functionName);
                throw new RestException(Response.Status.BAD_REQUEST, String.format("%s %s cannot be admitted:- %s",
                        ComponentTypeUtils.toString(componentType), functionName, e.getMessage()));
            }

            // merge from existing metadata
            Function.FunctionMetaData.Builder functionMetaDataBuilder = Function.FunctionMetaData.newBuilder().mergeFrom(existingComponent)
                    .setFunctionDetails(functionDetails);

            // update auth data if need
            if (worker().getWorkerConfig().isAuthenticationEnabled()) {
                if (clientAuthenticationDataHttps != null && updateOptions != null && updateOptions.isUpdateAuthData()) {
                    // get existing auth data if it exists
                    Optional<FunctionAuthData> existingFunctionAuthData = Optional.empty();
                    if (functionMetaDataBuilder.hasFunctionAuthSpec()) {
                        existingFunctionAuthData = Optional.ofNullable(getFunctionAuthData(Optional.ofNullable(functionMetaDataBuilder.getFunctionAuthSpec())));
                    }

                    try {
                        Optional<FunctionAuthData> newFunctionAuthData = worker().getFunctionRuntimeManager()
                                .getRuntimeFactory()
                                .getAuthProvider()
                                .updateAuthData(
                                        tenant, namespace,
                                        functionName, existingFunctionAuthData,
                                        clientAuthenticationDataHttps);

                        if (newFunctionAuthData.isPresent()) {
                            functionMetaDataBuilder.setFunctionAuthSpec(
                                    Function.FunctionAuthenticationSpec.newBuilder()
                                            .setData(ByteString.copyFrom(newFunctionAuthData.get().getData()))
                                            .build());
                        } else {
                            functionMetaDataBuilder.clearFunctionAuthSpec();
                        }
                    } catch (Exception e) {
                        log.error("Error updating authentication data for {} {}/{}/{}", ComponentTypeUtils.toString(componentType), tenant, namespace, functionName, e);
                        throw new RestException(Response.Status.INTERNAL_SERVER_ERROR, String.format("Error caching authentication data for %s %s:- %s", ComponentTypeUtils.toString(componentType), functionName, e.getMessage()));
                    }
                }
            }

            Function.PackageLocationMetaData.Builder packageLocationMetaDataBuilder;
            if (isNotBlank(functionPkgUrl) || uploadedInputStream != null) {
                try {
                    packageLocationMetaDataBuilder = getFunctionPackageLocation(functionMetaDataBuilder.build(),
                            functionPkgUrl, fileDetail, componentPackageFile);
                } catch (Exception e) {
                    log.error("Failed process {} {}/{}/{} package: ", ComponentTypeUtils.toString(componentType), tenant, namespace, functionName, e);
                    throw new RestException(Response.Status.INTERNAL_SERVER_ERROR, e.getMessage());
                }
            } else {
                packageLocationMetaDataBuilder = Function.PackageLocationMetaData.newBuilder().mergeFrom(existingComponent.getPackageLocation());
            }

            functionMetaDataBuilder.setPackageLocation(packageLocationMetaDataBuilder);

            updateRequest(functionMetaDataBuilder.build());
        } finally {
            if (!(functionPkgUrl != null && functionPkgUrl.startsWith(Utils.FILE))
                    && componentPackageFile != null && componentPackageFile.exists()) {
                componentPackageFile.delete();
            }
        }
    }

    private class GetFunctionStatus extends GetStatus<FunctionStatus, FunctionStatus.FunctionInstanceStatus.FunctionInstanceStatusData> {

        @Override
        public FunctionStatus.FunctionInstanceStatus.FunctionInstanceStatusData notScheduledInstance() {
            FunctionStatus.FunctionInstanceStatus.FunctionInstanceStatusData functionInstanceStatusData
                    = new FunctionStatus.FunctionInstanceStatus.FunctionInstanceStatusData();
            functionInstanceStatusData.setRunning(false);
            functionInstanceStatusData.setError("Function has not been scheduled");
            return functionInstanceStatusData;
        }

        @Override
        public FunctionStatus.FunctionInstanceStatus.FunctionInstanceStatusData fromFunctionStatusProto(
                InstanceCommunication.FunctionStatus status,
                String assignedWorkerId) {
            FunctionStatus.FunctionInstanceStatus.FunctionInstanceStatusData functionInstanceStatusData
                    = new FunctionStatus.FunctionInstanceStatus.FunctionInstanceStatusData();
            functionInstanceStatusData.setRunning(status.getRunning());
            functionInstanceStatusData.setError(status.getFailureException());
            functionInstanceStatusData.setNumRestarts(status.getNumRestarts());
            functionInstanceStatusData.setNumReceived(status.getNumReceived());
            functionInstanceStatusData.setNumSuccessfullyProcessed(status.getNumSuccessfullyProcessed());
            functionInstanceStatusData.setNumUserExceptions(status.getNumUserExceptions());

            List<ExceptionInformation> userExceptionInformationList = new LinkedList<>();
            for (InstanceCommunication.FunctionStatus.ExceptionInformation exceptionEntry : status.getLatestUserExceptionsList()) {
                ExceptionInformation exceptionInformation = getExceptionInformation(exceptionEntry);
                userExceptionInformationList.add(exceptionInformation);
            }
            functionInstanceStatusData.setLatestUserExceptions(userExceptionInformationList);

            // For regular functions source/sink errors are system exceptions
            functionInstanceStatusData.setNumSystemExceptions(status.getNumSystemExceptions()
                    + status.getNumSourceExceptions() + status.getNumSinkExceptions());
            List<ExceptionInformation> systemExceptionInformationList = new LinkedList<>();
            for (InstanceCommunication.FunctionStatus.ExceptionInformation exceptionEntry : status.getLatestSystemExceptionsList()) {
                ExceptionInformation exceptionInformation = getExceptionInformation(exceptionEntry);
                systemExceptionInformationList.add(exceptionInformation);
            }
            for (InstanceCommunication.FunctionStatus.ExceptionInformation exceptionEntry : status.getLatestSourceExceptionsList()) {
                ExceptionInformation exceptionInformation = getExceptionInformation(exceptionEntry);
                systemExceptionInformationList.add(exceptionInformation);
            }
            for (InstanceCommunication.FunctionStatus.ExceptionInformation exceptionEntry : status.getLatestSinkExceptionsList()) {
                ExceptionInformation exceptionInformation = getExceptionInformation(exceptionEntry);
                systemExceptionInformationList.add(exceptionInformation);
            }
            functionInstanceStatusData.setLatestSystemExceptions(systemExceptionInformationList);

            functionInstanceStatusData.setAverageLatency(status.getAverageLatency());
            functionInstanceStatusData.setLastInvocationTime(status.getLastInvocationTime());
            functionInstanceStatusData.setWorkerId(assignedWorkerId);

            return functionInstanceStatusData;
        }

        @Override
        public FunctionStatus.FunctionInstanceStatus.FunctionInstanceStatusData notRunning(String assignedWorkerId, String error) {
            FunctionStatus.FunctionInstanceStatus.FunctionInstanceStatusData functionInstanceStatusData
                    = new FunctionStatus.FunctionInstanceStatus.FunctionInstanceStatusData();
            functionInstanceStatusData.setRunning(false);
            if (error != null) {
                functionInstanceStatusData.setError(error);
            }
            functionInstanceStatusData.setWorkerId(assignedWorkerId);

            return functionInstanceStatusData;
        }

        @Override
        public FunctionStatus getStatus(String tenant, String namespace, String name, Collection<Function.Assignment>
                assignments, URI uri) throws PulsarAdminException {
            FunctionStatus functionStatus = new FunctionStatus();
            for (Function.Assignment assignment : assignments) {
                boolean isOwner = worker().getWorkerConfig().getWorkerId().equals(assignment.getWorkerId());
                FunctionStatus.FunctionInstanceStatus.FunctionInstanceStatusData functionInstanceStatusData;
                if (isOwner) {
                    functionInstanceStatusData = getComponentInstanceStatus(tenant, namespace, name, assignment
                            .getInstance().getInstanceId(), null);
                } else {
                    functionInstanceStatusData = worker().getFunctionAdmin().functions().getFunctionStatus(
                            assignment.getInstance().getFunctionMetaData().getFunctionDetails().getTenant(),
                            assignment.getInstance().getFunctionMetaData().getFunctionDetails().getNamespace(),
                            assignment.getInstance().getFunctionMetaData().getFunctionDetails().getName(),
                            assignment.getInstance().getInstanceId());
                }

                FunctionStatus.FunctionInstanceStatus instanceStatus = new FunctionStatus.FunctionInstanceStatus();
                instanceStatus.setInstanceId(assignment.getInstance().getInstanceId());
                instanceStatus.setStatus(functionInstanceStatusData);
                functionStatus.addInstance(instanceStatus);
            }

            functionStatus.setNumInstances(functionStatus.instances.size());
            functionStatus.getInstances().forEach(functionInstanceStatus -> {
                if (functionInstanceStatus.getStatus().isRunning()) {
                    functionStatus.numRunning++;
                }
            });
            return functionStatus;
        }

        @Override
        public FunctionStatus getStatusExternal(final String tenant,
                                                final String namespace,
                                                final String name,
                                                final int parallelism) {
            FunctionStatus functionStatus = new FunctionStatus();
            for (int i = 0; i < parallelism; ++i) {
                FunctionStatus.FunctionInstanceStatus.FunctionInstanceStatusData functionInstanceStatusData
                        = getComponentInstanceStatus(tenant, namespace, name, i, null);
                FunctionStatus.FunctionInstanceStatus functionInstanceStatus
                        = new FunctionStatus.FunctionInstanceStatus();
                functionInstanceStatus.setInstanceId(i);
                functionInstanceStatus.setStatus(functionInstanceStatusData);
                functionStatus.addInstance(functionInstanceStatus);
            }

            functionStatus.setNumInstances(functionStatus.instances.size());
            functionStatus.getInstances().forEach(functionInstanceStatus -> {
                if (functionInstanceStatus.getStatus().isRunning()) {
                    functionStatus.numRunning++;
                }
            });
            return functionStatus;
        }

        @Override
        public FunctionStatus emptyStatus(final int parallelism) {
            FunctionStatus functionStatus = new FunctionStatus();
            functionStatus.setNumInstances(parallelism);
            functionStatus.setNumRunning(0);
            for (int i = 0; i < parallelism; i++) {
                FunctionStatus.FunctionInstanceStatus functionInstanceStatus = new FunctionStatus.FunctionInstanceStatus();
                functionInstanceStatus.setInstanceId(i);
                FunctionStatus.FunctionInstanceStatus.FunctionInstanceStatusData functionInstanceStatusData
                        = new FunctionStatus.FunctionInstanceStatus.FunctionInstanceStatusData();
                functionInstanceStatusData.setRunning(false);
                functionInstanceStatusData.setError("Function has not been scheduled");
                functionInstanceStatus.setStatus(functionInstanceStatusData);

                functionStatus.addInstance(functionInstanceStatus);
            }

            return functionStatus;
        }
    }

    private ExceptionInformation getExceptionInformation(InstanceCommunication.FunctionStatus.ExceptionInformation exceptionEntry) {
        ExceptionInformation exceptionInformation
                = new ExceptionInformation();
        exceptionInformation.setTimestampMs(exceptionEntry.getMsSinceEpoch());
        exceptionInformation.setExceptionString(exceptionEntry.getExceptionString());
        return exceptionInformation;
    }

    /**
     * Get status of a function instance.  If this worker is not running the function instance,
     * @param tenant the tenant the function belongs to
     * @param namespace the namespace the function belongs to
     * @param componentName the function name
     * @param instanceId the function instance id
     * @return the function status
     */
    public FunctionStatus.FunctionInstanceStatus.FunctionInstanceStatusData getFunctionInstanceStatus(final String tenant,
                                                                                                      final String namespace,
                                                                                                      final String componentName,
                                                                                                      final String instanceId,
                                                                                                      final URI uri,
                                                                                                      final String clientRole,
                                                                                                      final AuthenticationDataSource clientAuthenticationDataHttps) {

        // validate parameters
        componentInstanceStatusRequestValidate(tenant, namespace, componentName, Integer.parseInt(instanceId), clientRole, clientAuthenticationDataHttps);

        FunctionStatus.FunctionInstanceStatus.FunctionInstanceStatusData functionInstanceStatusData;
        try {
            functionInstanceStatusData = new GetFunctionStatus().getComponentInstanceStatus(tenant, namespace, componentName,
                    Integer.parseInt(instanceId), uri);
        } catch (WebApplicationException we) {
            throw we;
        } catch (Exception e) {
            log.error("{}/{}/{} Got Exception Getting Status", tenant, namespace, componentName, e);
            throw new RestException(Response.Status.INTERNAL_SERVER_ERROR, e.getMessage());
        }

        return functionInstanceStatusData;
    }

    /**
     * Get statuses of all function instances.
     * @param tenant the tenant the function belongs to
     * @param namespace the namespace the function belongs to
     * @param componentName the function name
     * @return a list of function statuses
     * @throws PulsarAdminException
     */
    public FunctionStatus getFunctionStatus(final String tenant,
                                            final String namespace,
                                            final String componentName,
                                            final URI uri,
                                            final String clientRole,
                                            final AuthenticationDataSource clientAuthenticationDataHttps) {

        // validate parameters
        componentStatusRequestValidate(tenant, namespace, componentName, clientRole, clientAuthenticationDataHttps);

        FunctionStatus functionStatus;
        try {
            functionStatus = new GetFunctionStatus().getComponentStatus(tenant, namespace, componentName, uri);
        } catch (WebApplicationException we) {
            throw we;
        } catch (Exception e) {
            log.error("{}/{}/{} Got Exception Getting Status", tenant, namespace, componentName, e);
            throw new RestException(Response.Status.INTERNAL_SERVER_ERROR, e.getMessage());
        }

        return functionStatus;
    }

    private Function.FunctionDetails validateUpdateRequestParams(final String tenant,
                                                                 final String namespace,
                                                                 final String componentName,
                                                                 final FunctionConfig functionConfig,
                                                                 final File componentPackageFile) throws IOException {

        // The rest end points take precedence over whatever is there in function config
        functionConfig.setTenant(tenant);
        functionConfig.setNamespace(namespace);
        functionConfig.setName(componentName);
        FunctionConfigUtils.inferMissingArguments(functionConfig);
        ClassLoader clsLoader = FunctionConfigUtils.validate(functionConfig, componentPackageFile);
        return FunctionConfigUtils.convert(functionConfig, clsLoader);

    }
}