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| 1 | +--- |
| 2 | +title: Level Up Your Serverless Game |
| 3 | +author: Lena Fuhrimann |
| 4 | +comments: true |
| 5 | +date: 2025-09-25 |
| 6 | +--- |
| 7 | + |
| 8 | +Is your serverless project running into unexpected snags? You're not alone. From |
| 9 | +basic misconfigurations to frustrating deployment nightmares, we've seen the |
| 10 | +same pitfalls trap countless teams. This guide is your cheat sheet to avoiding |
| 11 | +those common mistakes and accelerating your journey to serverless mastery. Think |
| 12 | +of each level as a lesson learned—a mistake you don't have to make. From basic |
| 13 | +misconfigurations to complex deployment nightmares, the patterns are |
| 14 | +frustratingly consistent. We've compiled this blog post to help you avoid these |
| 15 | +common pitfalls and accelerate your journey to serverless excellence. Think of |
| 16 | +each level as a lesson learned, a mistake you don't have to make. To learn more |
| 17 | +about the details and apply the learnings yourself, follow our open source |
| 18 | +[Serverless Workshop](https://github.com/bespinian/serverless-workshop). This |
| 19 | +blog post as well as the workshop both use AWS Lambda but the learnings can be |
| 20 | +applied to any function as a service (FaaS) platform. Now, let's dive in. |
| 21 | + |
| 22 | +## Level 0 - This is easy! |
| 23 | + |
| 24 | +**⚠️ Mistake: None yet** |
| 25 | + |
| 26 | +To get started, we need to create our first function. Many projects jump into |
| 27 | +complex architectures without understanding the fundamentals, leading to |
| 28 | +confusion and wasted effort. This level is about demystifying the basic |
| 29 | +mechanics of serverless: understanding how to create a function, configure its |
| 30 | +runtime, and pass parameters using environment variables. You should also get |
| 31 | +acquainted with your cloud provider's permission model, a cornerstone of secure |
| 32 | +serverless applications. By adding an HTTP trigger through an API gateway, you |
| 33 | +can transform our function into a web-accessible service, making it tangible and |
| 34 | +interactive. |
| 35 | + |
| 36 | +**✅ Start as simple and small as possible and take it from there.** |
| 37 | + |
| 38 | +## Level 1: Loggin' it! |
| 39 | + |
| 40 | +**⚠️ Mistake: Lack of structured logging** |
| 41 | + |
| 42 | +Having deployed our first function, we have no idea what it does and if it |
| 43 | +succeeds or not. When things go wrong, it's very hard to debug and investigate |
| 44 | +issues. Many serverless projects suffer from poor observability, making |
| 45 | +troubleshooting a nightmare. Using structured logging (e.g., formatted as JSON), |
| 46 | +we get a set of logs that we can query and which give us custom insights into |
| 47 | +what our function does. We'll know if it succeeds or fails in doing so and get |
| 48 | +context about what went wrong if things don't go as expected. Such a log line |
| 49 | +could look as follows: |
| 50 | + |
| 51 | +```json |
| 52 | +{ |
| 53 | + "correlationId": "9ac54d82-75e0-4f0d-ae3c-e84ca400b3bd", |
| 54 | + "requestId": "58d9c96e-ae9f-43db-a353-c48e7a70bfa8", |
| 55 | + "commitHash": "9d9154e", |
| 56 | + "level": "INFO", |
| 57 | + "requestPath": "/users/1", |
| 58 | + "requestMethod": "GET", |
| 59 | + "responseCode": 200, |
| 60 | + "responseBody": "All good" |
| 61 | +} |
| 62 | +``` |
| 63 | + |
| 64 | +**✅ Don't wait until production issues arise to implement structured logging.** |
| 65 | + |
| 66 | +## Level 2: Tracin' it! |
| 67 | + |
| 68 | +**⚠️ Mistake: Lack of distributed tracing** |
| 69 | + |
| 70 | +As your serverless applications grow, understanding the flow of requests becomes |
| 71 | +critical. Distributed tracing provides invaluable insights into performance |
| 72 | +bottlenecks and errors. Most cloud providers provide comprehensive toolsets to |
| 73 | +easily add tracing IDs and even trace HTTP calls and other function calls by |
| 74 | +just adding a couple of lines of code. Therefore, it's usually quite cheap to |
| 75 | +add tracing and the value it provides is quite large. A low-hanging fruit you |
| 76 | +shouldn't miss out on. |
| 77 | + |
| 78 | +**✅ Activate distributed tracing for all your functions.** |
| 79 | + |
| 80 | +## Level 3: Timin' it! |
| 81 | + |
| 82 | +**⚠️ Mistake: Function timeouts not handled gracefully** |
| 83 | + |
| 84 | +Functions operate within time constraints, making it essential to handle |
| 85 | +timeouts gracefully. Unhandled timeouts can lead to unexpected behavior and data |
| 86 | +inconsistencies. We need to ensure our functions terminate cleanly and |
| 87 | +predictably, even when approaching their time limits. To achieve that, simply |
| 88 | +monitor the remaining execution time and implement mechanisms for aborting |
| 89 | +long-running operations with enough time left. This allows to either perform a |
| 90 | +proper cleanup or partial results instead, ensuring a smooth and reliable user |
| 91 | +experience. |
| 92 | + |
| 93 | +**✅ Don't let timeouts cause chaos in your application.** |
| 94 | + |
| 95 | +## Level 4: Optimized Cold Starts! |
| 96 | + |
| 97 | +**⚠️ Mistake: Ignoring cold start performance** |
| 98 | + |
| 99 | +Cold starts, the initial latency experienced when a Lambda function is invoked |
| 100 | +after a period of inactivity, can impact performance. In latency-sensitive |
| 101 | +applications, even a few extra milliseconds can be noticeable to users. This |
| 102 | +level explores techniques to minimize cold start times, such as moving |
| 103 | +initialization code outside the handler. By optimizing our function's startup |
| 104 | +process, we can enhance responsiveness and improve the overall user experience. |
| 105 | + |
| 106 | +**✅ Optimize for cold starts early to avoid performance bottlenecks later.** |
| 107 | + |
| 108 | +## Level 5: Decoupled! |
| 109 | + |
| 110 | +⚠️ Mistake: Tight coupling |
| 111 | + |
| 112 | +As your serverless applications grow, the need for asynchronous communication |
| 113 | +becomes essential. Without it, services are often tightly coupled, meaning a |
| 114 | +failure in one can cause a domino effect of failures throughout your entire |
| 115 | +system. This level introduces Amazon SQS, a simple yet powerful message queuing |
| 116 | +service. Think of it as a waiting room for messages; your function can drop off |
| 117 | +a message and move on to other tasks, while another function can pick it up |
| 118 | +later when it's ready. This decoupling creates more scalable and resilient |
| 119 | +architectures, making your application much more robust. |
| 120 | + |
| 121 | +✅ Use message queues like SQS to decouple services and build a more resilient |
| 122 | +system. |
| 123 | + |
| 124 | +## Level 6: Infrastructure as Code! |
| 125 | + |
| 126 | +⚠️ Mistake: Manual infrastructure management |
| 127 | + |
| 128 | +Managing cloud resources manually is slow, inconsistent, and highly prone to |
| 129 | +human error. It's a recipe for chaos, especially as your application scales. |
| 130 | +This level is all about adopting Infrastructure as Code (IaC) using a tool like |
| 131 | +Terraform. By defining your serverless functions and their dependencies in a |
| 132 | +configuration file, you can treat your infrastructure like any other code. This |
| 133 | +means repeatable, version-controlled deployments that are consistent across all |
| 134 | +your environments. |
| 135 | + |
| 136 | +✅ Stop clicking around in the console and start managing your infrastructure |
| 137 | +with code. |
| 138 | + |
| 139 | +## Level 7: Testing it All! |
| 140 | + |
| 141 | +⚠️ Mistake: Lack of testing |
| 142 | + |
| 143 | +Developing without a safety net is risky business. Untested code is a disaster |
| 144 | +waiting to happen and can lead to bugs, unexpected behavior, and production |
| 145 | +outages. This level tackles the critical practice of unit testing and local |
| 146 | +execution for your functions. By writing tests that check your code's behavior |
| 147 | +and running them locally, you can catch errors early and ensure your functions |
| 148 | +are reliable before they ever hit production. |
| 149 | + |
| 150 | +✅ Don't just hope your code works—test it to be sure. |
| 151 | + |
| 152 | +## Level 8: Securin it! |
| 153 | + |
| 154 | +⚠️ Mistake: Overly permissive roles |
| 155 | + |
| 156 | +Giving a function more permissions than it needs is like handing out a master |
| 157 | +key to your entire house. It creates a massive security vulnerability. This |
| 158 | +level is about applying the principle of least privilege, which means granting |
| 159 | +your functions only the absolute minimum permissions required to do their job. |
| 160 | +By meticulously defining and restricting access, you significantly reduce the |
| 161 | +potential damage from a security breach and strengthen your application's |
| 162 | +overall security posture. |
| 163 | + |
| 164 | +✅ Implement the principle of least privilege to lock down your serverless |
| 165 | +functions. |
| 166 | + |
| 167 | +## Level 9: The Gradual Rollout! |
| 168 | + |
| 169 | +⚠️ Mistake: Risky deployments |
| 170 | + |
| 171 | +Deploying a new version of your application to 100% of your users at once is a |
| 172 | +high-stakes gamble. If there's a problem, everyone feels the pain immediately. |
| 173 | +This level introduces a safer approach: canary deployments. Using a service like |
| 174 | +AWS CodeDeploy, you can automatically release a new version to a small subset of |
| 175 | +your users first. If the new version performs well, you can gradually roll it |
| 176 | +out to the rest. If not, you can roll it back quickly, minimizing the impact of |
| 177 | +any errors. |
| 178 | + |
| 179 | +✅ Minimize deployment risk by gradually rolling out new changes to your users. |
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