com.sap.cloud.sdk.frameworks.hystrix.ScpNeoHystrixConcurrencyStrategy Maven / Gradle / Ivy

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/*
 * Copyright (c) 2019 SAP SE or an SAP affiliate company. All rights reserved.
 */

package com.sap.cloud.sdk.frameworks.hystrix;

import java.util.concurrent.Callable;

import org.slf4j.Logger;

import com.netflix.hystrix.strategy.concurrency.HystrixConcurrencyStrategy;
import com.sap.cloud.sdk.cloudplatform.concurrency.ScpNeoTenantCallable;
import com.sap.cloud.sdk.cloudplatform.concurrency.ScpNeoUserSessionCallable;
import com.sap.cloud.sdk.cloudplatform.exception.ShouldNotHappenException;
import com.sap.cloud.sdk.cloudplatform.logging.CloudLoggerFactory;
import com.sap.cloud.sdk.cloudplatform.security.user.ScpNeoUser;
import com.sap.cloud.sdk.cloudplatform.security.user.User;
import com.sap.cloud.sdk.cloudplatform.security.user.UserAccessor;
import com.sap.cloud.sdk.cloudplatform.security.user.exception.UserAccessException;
import com.sap.cloud.sdk.cloudplatform.security.user.exception.UserNotAuthenticatedException;
import com.sap.cloud.sdk.cloudplatform.servlet.RequestContextAccessor;
import com.sap.cloud.sdk.cloudplatform.tenant.ScpNeoTenant;
import com.sap.cloud.sdk.cloudplatform.tenant.Tenant;
import com.sap.cloud.sdk.cloudplatform.tenant.TenantAccessor;
import com.sap.cloud.sdk.cloudplatform.tenant.exception.TenantAccessException;
import com.sap.cloud.sdk.cloudplatform.tenant.exception.TenantNotAvailableException;

/**
 * Implementation of a {@link HystrixConcurrencyStrategy} that adapts to the multi-tenant environment of SAP CP Neo,
 * initializing request variables and running the respective Hystrix {@link Callable}s within a request's tenant and
 * user context.
 */
public class ScpNeoHystrixConcurrencyStrategy extends HystrixConcurrencyStrategy
{
    private static final Logger logger = CloudLoggerFactory.getLogger(ScpNeoHystrixConcurrencyStrategy.class);

    private ScpNeoTenant getCurrentTenant()
        throws TenantNotAvailableException,
            TenantAccessException
    {
        final Tenant tenant = TenantAccessor.getCurrentTenant();

        if( !(tenant instanceof ScpNeoTenant) ) {
            throw new ShouldNotHappenException(
                "The current "
                    + Tenant.class.getSimpleName()
                    + " is not an instance of "
                    + ScpNeoTenant.class.getSimpleName()
                    + ". Please make sure to specify a dependency to com.sap.cloud.s4hana.cloudplatform:tenant-scp-neo.");
        }

        return (ScpNeoTenant) tenant;
    }

    private ScpNeoUser getCurrentUser()
        throws UserNotAuthenticatedException,
            UserAccessException
    {
        final User user = UserAccessor.getCurrentUser();

        if( !(user instanceof ScpNeoUser) ) {
            throw new ShouldNotHappenException(
                "The current "
                    + User.class.getSimpleName()
                    + " is not an instance of "
                    + ScpNeoUser.class.getSimpleName()
                    + ". Please make sure to specify a dependency to com.sap.cloud.s4hana.cloudplatform:security-scp-neo.");
        }

        return (ScpNeoUser) user;
    }

    @Override
    public  Callable wrapCallable( final Callable callable )
    {
        Callable userSessionCallable;

        try {
            userSessionCallable =
                new ScpNeoUserSessionCallable<>(
                    RequestContextAccessor.getCurrentRequest().orElse(null),
                    getCurrentUser(),
                    callable);

            if( logger.isDebugEnabled() ) {
                logger.debug("Successfully wrapped callable in " + userSessionCallable + ".");
            }
        }
        catch( final UserNotAuthenticatedException | UserAccessException e ) {
            if( logger.isDebugEnabled() ) {
                logger.debug(
                    "User not available. Skip wrapping of callable in "
                        + ScpNeoUserSessionCallable.class.getSimpleName()
                        + ".",
                    e);
            }
            userSessionCallable = callable;
        }

        Callable tenantCallable;

        try {
            tenantCallable = new ScpNeoTenantCallable<>(getCurrentTenant(), userSessionCallable);

            if( logger.isDebugEnabled() ) {
                logger.debug("Successfully wrapped callable in " + tenantCallable + ".");
            }
        }
        catch( final TenantNotAvailableException | TenantAccessException e ) {
            if( logger.isDebugEnabled() ) {
                logger.debug(
                    "Tenant not available. Skip wrapping of callable in "
                        + ScpNeoTenantCallable.class.getSimpleName()
                        + ".",
                    e);
            }
            tenantCallable = userSessionCallable;
        }

        return tenantCallable;
    }
}