Using Guzzle and PHPUnit for REST API Testing
APIs are increasingly becoming the backbone of the modern internet - whether you're ordering food from an app on your phone or browsing a blog using a modern JavaScript framework, chances are those requests are flowing through an API. Given the need for APIs to evolve through refactoring and extension, having great automated tests allows you to develop fast without needing to slow down to run manual tests to work out what’s broken. Additionally, by having tests in place you’re able to firmly identify the requirements that your API should meet, your API tests effectively form a tangible and executable specification. API Testing offers an end-to-end mechanism of testing the behaviour of your API which has advantages in both reliability and also development productivity.
In this post I'll be demonstrating how you can test RESTful APIs in an automated fashion using PHP, by building a testing framework through creative use of two packages - Guzzle and PHPUnit. The resulting tests will be something you can run outside of your API as part of your deployment or CI (Continuous Integration) process.
Guzzle acts as a powerful HTTP client which we can use to simulate HTTP Requests against our API. Though PHPUnit Continue reading
NVMe and NVMs: What To Expect
An overview of how new protocols impact storage performance.
How I Started Hating Automatic Context Switching in Cisco IOS
Here’s a trick question:
- Imagine you have a network running IPv4 and VPNv4 services;
- You want to use neighbor next-hop-self on IPv4 sessions, but not on VPNv4 sessions;
To implement this request you use the following configuration commands (plenty of other commands removed because they don’t impact the results):
router bgp 64500
address-family ipv4
maximum-paths ibgp 32
maximum-paths 32
neighbor 192.168.0.4 next-hop-self
neighbor 192.168.0.1 next-hop-self
address-family vpnv4
maximum-paths ibgp 32
maximum-paths 32
no neighbor 192.168.0.4 next-hop-self
no neighbor 192.168.0.1 next-hop-self
Try to figure out what the end-result will be without connecting to a router or reading the rest of this blog post.
Ok, here’s what totally threw me off (and wasted an hour of my life): next-hop-self is removed from neighbors in the IPv4 address family. Here’s why:
- There is no maximum-paths ibgp command in VPNv4 address family;
- The moment you enter maximum-paths ibgp command the configuration parser exits the address-family vpnv4 context and enters router bgp context;
- Because the ipv4 address family is the default context within router bgp (for legacy reasons) all the subsequent commands are executed within the address-family ipv4 context removing next-hop self from neighbors in IPv4 address family.
No wonder David Barroso named his library NAPALM (you’ll find the full story in this or this podcast).
ACL Trace in APIC EM
I wanted to take just a moment to share the output of an APIC-EM ACL Trace (option in Path Trace). For this example, I have built out the topology below.
The applicable configuration for CSR1000v-2 is as follows–
ip access-list extended TESTING permit ospf any any permit icmp any any permit tcp any any eq telnet deny tcp any any eq 22 permit ip any any ! interface GigabitEthernet2 description to csr1000v-1 ip address 10.0.0.6 255.255.255.252 ip access-group TESTING in ip ospf cost 1 negotiation auto cdp enable
For testing it is possible to run a path trace from 10.1.1.1 (LAN interface on CSR1000v-1) to 10.1.2.1 (LAN interface on CSR1000v-2) with TCP Ports. To expose the layer 4 options, it is necessary to choose more options. The check mark in the “ACL Trace” instructs APIC-EM to evaluate ACLs.
The output indicates a successful trace AND an allowed match through the ACL.
Adjusting the path trace to target TCP port 22 demonstrates how a blocked flow is represented in APIC-EM.
The one caveat I have found is that this is only ‘semi’ real time. APIC-EM downloads the configuration from its Continue reading
Many networks leverage what is known as a VRF. These are used for traffic isolation and create separate routing instances within a router. It is important that vrf awareness is confirmed for any service (DHCP, Voice GW, etc) being locally provided for a given point in the network. One use case for such a configuration might be for voice isolation with or without MPLS. In the case that a router is providing voice gateway functionality (i.e. FXO/FXS to VOIP), the voice functions must understand the VRF construct in order to properly fulfill the role.
TL;DR–This configuration sometimes does not behave as expected and, in my experience, may require a reboot after following the documented procedure.
The configuration for VRF-Aware H.323 and SIP for Voice Gateways can be found at the URL below.
http://www.cisco.com/c/en/us/td/docs/ios/12_4t/12_4t15/stork.html
Notice that it makes reference to the fact that the services need to be restarted–
To configure a voice VRF, you must shut down voice services on the gateway, assign a previously defined VPN VRF to the VoIP SPI, and then restart voice services.
As one researches this particular configuration, the concept of voice “multi-vrf” will likely come up. Based on my Continue reading