It might feel like yet another article on how to build Docker images for Node.js applications but many examples weve seen in blogs are very simplistic and solely aim to guide you on the basics of having a Node.js Docker image running an application, without thoughtful consideration of security and best practices for building Node.js Docker images. A simple code example should look as follows: Then run the container, and once its up specifically send it the SIGHUP signal using the docker CLI and the special --signal command line flag: Nothing happened, right? So, in fact, by specifying the following in your Dockerfile, you always build the latest version of the Docker image that has been built by the Node.js Docker working group: The shortcomings of building based on the default node image are as follows: In fact, the node Docker image is quite big and includes hundreds of security vulnerabilities of different types and severities. In both cases, I see a message while running the build "transferring context: 490.12kB". Many thanks to Bret Fisher from whom we learned many insightful Docker best practices, TL;DR: Use multi-stage build to copy only necessary production artifacts. Thats what I mean. It adds an unneeded security risk from packages used as development dependencies, as well as inflating the image size unnecessarily. Lets see with our own eyes. The node_modules inside the image is generated from the Dockerfile 'npm install' step. Lets fix it by updating the Dockerfile, providing the full base image tag for the Node.js version that corresponds to that SHA256 hash: The following Dockerfile directive installs all dependencies in the container, including devDependencies, which arent needed for a functional application to work. Unflagging nodepractices will restore default visibility to their posts. More like San Francis-go (Ep. Find centralized, trusted content and collaborate around the technologies you use most. 469). As a bonus the build time will significantly decrease. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Otherwise: Mistakenely the Dockerfile creator left Root as the production user and also used an image from an unknown source repository. Dockerfile and .dockerignore are gone. Drivetrain 1x12 or 2x10 for my MTB use case? Just like that principle in software development of Separation of Concerns, well apply the same ideas in order to build our Node.js Docker images. Most blog articles weve seen start and finish along the lines of the following basic Dockerfile instructions for building Node.js Docker images: Copy that to a file named Dockerfile, then build and run it. We're a place where coders share, stay up-to-date and grow their careers. This has two downsides. Snyk is a developer security platform. Templates let you quickly answer FAQs or store snippets for re-use. Lets put this test into practice. That first image that well refer to as the build image, gets discarded and is left as a dangling image in the Docker host that built it, until it gets cleaned. Made with love and Ruby on Rails. PM2, Cluster module). Developers are often led to believe that specifying the latest tag will provide them with the most recent image in the repository however this is not the case. In Dockerized runtimes shutting down containers is not a rare event, rather a frequent occurrence that happen as part of routine work. Why is it important? Therefore, the prudent thing is to keep node_modules inside .dockerignore file to achieve more efficiency in the docker build process. Just like were using. Otherwise: Docker build will be very long and consume a lot of resources even when making tiny changes. Not only that, but we can also use a bigger Docker base image to install our dependencies, compile any native npm packages if needed, and then copy all these artifacts into a small production base image, like our alpine example. /usr/src/app from the 2nd Dockerfile stage, were also copying over any local node_modules/ to the Docker image. Perhaps it also needs a specific proxy or registry configuration to pull packages from. This means that it makes sense to have the .npmrc file available to the build stagehowever, we dont need it at all in the second stage for the production image, nor do we want it there as it may include sensitive information, like the secret npm token. Thanks for keeping DEV Community safe. Mostly, these are signals to terminate an application, such as. Ill walk you through the differences between them and why theyre all patterns to avoid. When processes run as PID 1 they effectively take on some of the responsibilities of an init system, which is typically responsible for initializing an operating system and processes. The way to go about it then is to use a tool that will act like an init process, in that it is invoked with PID 1, then spawns our Node.js application as another process whilst ensuring that all signals are proxied to that Node.js process. Everything went smoothly, until I tried to add the .dockerignore file, where I listed the following files in it, expecting that they won't get copied into the docker image: So I trashed and rebuilt my image with the existing Dockerfile and the new .dockerignore file. This can be avoided by coping a secret file like .npmrc and then removing it using multi-stage build (beware, build history should be deleted as well) or by using Docker build-kit secret feature which leaves zero traces, Otherwise: Everyone with access to the CI and docker registry will also get access to some precious organization secrets as a bonus, TL;DR: Besides checking code dependencies vulnerabilities also scan the final image that is shipped to production. With you every step of your journey. The official node Docker image, as well as its variants like alpine, include a least-privileged user of the same name: node. COPY package*.json ./ in Dockerfile. It falls back to sorting by highest score if no posts are trending. I'm not sure. Then youve come to the right place! and only accessible to Node.JS Practices. You could attempt to improve it by deleting it afterwards, like this: However, now the .npmrc file is available in a different layer of the Docker image. Finding alternative images could be very time consuming, so Snyk saves you that trouble. Once unpublished, all posts by nodepractices will become hidden and only accessible to themselves. Software Developer Engineer In Test at Team International. Heres how well set it up: This brings us to the following up to date Dockerfile. Do not install package only for convenience, this is a production app. Remember how we discussed the importance of small Docker base images for our Node.js applications? TL;DR: Large images lead to higher exposure to vulnerabilities and increased resource consumption. If that process happens to be root then they can do virtually everything within the container, including attempting a container escape or privilege escalation. That last step wraps up this entire guide on containerizing Node.js Docker web applications, taking into consideration performance and security related optimizations to ensure were building production-grade Node.js Docker images! Where do you end up when you cast Dimension Door from an extradimensional space? the shellform notation, in which the container spawns a shell interpreter that wraps the process. Once unpublished, this post will become invisible to the public Once suspended, nodepractices will not be able to comment or publish posts until their suspension is removed. 468), Monitoring data quality with Bigeye(Ep. Great job! I have a similar observation i.e. Firstly a bigger image means a bigger download size which, besides increasing the storage requirement, means more time to download and re-build the image. Lets test that with Snyk: While it seems that a specific Node.js runtime version such as FROM node:14.2.0-slim is good enough, Snyk is able to find security vulnerabilities from 2 primary sources: The best part of this Snyk CLI report? While these vulnerable versions in the container may not pose immediate threat, why have them if were not using them? have overwritten node_modules anyway? eslint-scope), TL;DR: Handle the process SIGTERM event and clean-up all existing connection and resources. Thanks for the article, but what happens when you work in development and need NPM packages for autocompletion in your IDE, how do you handle best practices here? This could be avoided with just a simple linter. Heres a stock Fastify web application example, with an inherent delayed response of 60 seconds for an endpoint: Run this application and once its running send a simple HTTP request to this endpoint: Hit CTRL+C in the running Node.js console window and youll see that the curl request exited abruptly. In which European countries is illegal to publicly state an opinion that in the US would be protected by the first amendment? Here is the result: Snyk detected 16 operating system dependencies, including our Node.js runtime executable, and did not find any vulnerable versions. One such tool that we use at Snyk is dumb-init because it is statically linked and has a small footprint. If nodepractices is not suspended, they can still re-publish their posts from their dashboard. ", Oscillating instrumentation amplifier with transformer coupled input, Chi squared test with reasonable sample size results in R warning. Tooling and libraries installed in this debian base image, such as glibc, bzip2, gcc, perl, bash, tar, libcrypt and others. this is superb, really good stuff and very detailed explanation. Youll find it helpful regardless of the Node.js application you aim to build. Snyk also recommends other base images to switch to, so you dont have to figure this out yourself. Lets begin improving this Dockerfile so we can build optimized Node.js web applications with Docker. Note that each and every bullet has a link to detailed information and code examples. Build arguments passed like that to Docker are kept in the history log. Otherwise: Larger images will take longer to build and ship, build-only tools might contain vulnerabilities and secrets only meant for the build phase might be leaked. Also, now, do you see that NPM_TOKEN passed as build argument to the build intermediary Docker image? In the Dockerfile, we will add flags to the. Does sitecore child item in draft state gets published when deep=1 is set on Parent. Otherwise: When no signals are passed, your code will never be notified about shutdowns. Inspecting the produced image using tools like Dive can easily help to identify such issues, TL;DR: While pulling base or final images, the network might be mislead and redirected to download malicious images. That's pretty insignificant and surely it's not transferring the node_modules folder. That will be our first stage. The recommendations for building better Docker images are: Based on this, lets ensure that we use the Long Term Support (LTS) version of Node.js, and the minimal alpine image type to have the smallest size and software footprint on the image: Nonetheless, this base image directive will still pull new builds of that tag. Not the greatest user experience. A better improvement would be as follows: The problem now is that the Dockerfile itself needs to be treated as a secret asset, because it contains the secret npm token inside it. It doesn't make any sense to duplicate the dependencies for faster future installs since there won't be any further installs - A Docker image is immutable. The following concerns are key in order to understanding the context for properly running and terminating Node.js Docker applications: Equipped with that knowledge, lets begin investigating the ways of invoking the process for a container, starting off with the example from the Dockerfile were building: The caveat here is two fold. This simulates the same experience your users would receive when containers tear down. Its not visible anymore in the docker history nodejs-tutorial command output because it doesnt exist in our production docker image. Make sure that in your Node.js application you set an event handler for the SIGHUP signal which logs to the console every time youre sending an event. Youre right, we dont. Thats how Docker works by default. To quote the Node.js Docker working group recommendation on this: Node.js was not designed to run as PID 1 which leads to unexpected behaviour when running inside of Docker. So I am testing creation of a docker image/container with a nodejs app usiung Dockerfile. Use small Docker imagesthis will translate to a smaller software footprint on the Docker image reducing the potential vulnerability vectors, and a smaller size, which will speed up the image build process. Putting aside our opinion on whether this is a good or bad practice for frameworks to take, it is important to know this. One way to mitigate this .dockerignore caveat is to mount a local file system that will be available for the build stage, but theres a better way. the execform notation, which directly spawns a process without wrapping it in a shell. We use cookies to ensure you get the best experience on our website.Read moreRead moreGot it. Consider docker as a entire new box, where everything will be installed and given commands to run specific tasks. Posted on Aug 16, 2020 Using a single line of code tens of MB (typically 10-50% of the image size) are shaved off, Otherwise: The image that will get shipped to production will weigh 30% more due to files that will never get used. Integrating directly into development tools, workflows, and automation pipelines, Snyk makes it easy for teams to find, prioritize, and fix security vulnerabilities in code, dependencies, containers, and infrastructure as code. To provide a better experience, we can do the following: Specifically with Fastify, we can have our handler call on fastify.close() which returns a promise that we will await, and Fastify will also take care to respond to every new connection with the HTTP status code 503 to signal that the application is unavailable. Create .dockerignore file and ignore all files which you think you don't want to include or let docker handles from itself. If thats the case, then you probably needed to find some way to make that secret NPM_TOKEN available to the npm install. Whos to say that the npm CLI forwards all events to the node runtime? TL;DR: use CMD ['node','server.js'] to start your app, avoid using npm scripts which don't pass OS signals to the code. Built on Forem the open source software that powers DEV and other inclusive communities. The take-away here for a .dockerignore file is: One thing to note about the .dockerignore file is that it is an all or nothing approach and cant be turned on or off per build stages in a Docker multi-stage build. It actually doesnt, and we can easily test that. If were already discussing process signals that terminate applications, lets make sure were shutting them down properly and gracefully without disrupting users. TL;DR: Avoid secrets leaking from the Docker build environment. It may seem to be an obvious choice to build your image based on the node Docker image, but what are you actually pulling in when you build the image? the comment I received was that if I left out the node_modules from the .dockerignore file, then the docker build process would have slowed down due to unnecessary copying of the node_modules, PLUS the image would have been larger. This is rarely needed and as a rule of thumb one should use the 'node' user that is created within official Node images, TL;DR: Sometimes it's easy to overlook side effects in the build process like leaked secrets or unnecessary files. Thats how it is with securitysometimes the obvious things are yet just another pitfall. Should Kubernetes be aware of that, it could relocate it to a different roomy instance, TL;DR: Include a .dockerignore file that filters out common secret files and development artifacts. After the creation, I ran docker run -it --entrypoint sh to check if those files/folders do not appear anymore. Achieving this demands some thoughtful code to orchestrate several moving parts: The load balancer, keep-alive connections, the HTTP server and other resources, Otherwise: Dying immediately means not responding to thousands of disappointed users, TL;DR: Always configure a memory limit using both Docker and the JavaScript runtime flags. Is it legal to download and run pirated abandonware because I'm curious about the software? Here is the update to our Dockerfile that represents our progress so far, but separated into two stages: As you can see, I chose a bigger image for the build stage because I might need tooling like gcc (the GNU Compiler Collection) to compile native npm packages, or for other needs. The Expanse: Sustained Gs during space travel, Debugging gurobipy VRP implementation output that gives no error message. We also have, Saves you from secrets exposure such as credentials in the contents of. Why would we want to risk it? How to customize the configuration file of the official PostgreSQL Docker image? These are publicly known security issues in the Node.js runtime. Here is how it works: Lets see how all of it works together. You can follow along this tutorial by cloning this repository. Use the Docker image digest, which is the static SHA256 hash of the image. It is full of mistakes and bad practices for building Node.js Docker images. This special treatment from the kernel means that the handling of a SIGTERM signal to a running process wont invoke a default fallback behavior of killing the process if the process doesnt already set a handler for it. Ideally, we would want to use the .npmrc file in the build stage, as we may need it because it includes a secret npm token to access private npm packages. Making statements based on opinion; back them up with references or personal experience. The threat assessment is pretty straight-forwardif an attacker is able to compromise the web application in a way that allows for command injection or directory path traversal, then these will be invoked with the user who owns the application process. Thought I'd just wanted to share this. The second Docker image, representing the second stage of the Docker build, will be the production Docker image. To learn more, see our tips on writing great answers. Multi-stage builds are an easy way to get rid of overweight and security threats. Using leaner Docker images, such as Slim and Alpine Linux variants, mitigates this issue. If youre building Docker images for work, theres a high chance that you also maintain private npm packages. The same applies to Docker images. In addition, referring to an image tag means that the base image is subject to change, as image tags cannot be relied upon for a deterministic install. Instead, if a deterministic install is expected, a SHA256 digest can be used to reference an exact image. If this Docker image is public, or someone is able to access it somehow, then your token is compromised. attack surface) is minimized. Avoid the above by all means. In the case of building a Docker image for production we want to ensure that we only install production dependencies in a deterministic way, and this brings us to the following recommendation for the best practice for installing npm dependencies in a container image: The updated Dockerfile contents in this stage are as follows: When you build your Node.js Docker image for production, you want to ensure that all frameworks and libraries are using the optimal settings for performance and security. If you are managing your Docker images in a registry, such as Docker Hub or Artifactory, you can easily, Use the Snyk CLI in your CI automation. DEV Community 2016 - 2022. TL;DR: This is a collection of Docker advice that is not related directly to Node.js - the Node implementation is not much different than any other language: TL;DR: COPY is safer as it copies local files only while ADD supports fancier fetches like downloading binaries from remote sites, TL;DR: Updating the local binaries during build (e.g. They are owned by root. By doing so, you might prevent secrets from leaking into the image. You can easily simulate this problem. You can sign up for a free Snyk account here. Connect and share knowledge within a single location that is structured and easy to search. If youre using it, then by default your starting point is going to be a baseline of 642 security vulnerabilities, and hundreds of megabytes of image data that is downloaded on every pull and build. Download the cheatsheet here. Join the DevSecOps Community on Discord to discuss this topic and more with other security-focused practitioners. How do I change the sans serif font in my document? Thats a big no-no as we may be copying over modified source code inside node_modules/. Confusion with node_modules being ignored by .dockerignore, San Francisco? The node Docker image is based on a full-fledged operating system, full of libraries and tools that you may or may not need to run your Node.js web application. How do I politely refuse/cut-off a person who needs me only when they want something? Luckily, Docker supports a way to pass arguments into the build process: I know you were thinking that were all done at this point but, sorry to disappoint . Nothing in the standard Docker protocol prevents this unless signing and verifying the content. TL;DR: Specify an explicit image digest or versioned label, never refer to 'latest'. On top of that, since were using the wild-card COPY . Docker image scanners check the code dependencies but also the OS binaries. Docker repository), TL;DR: Although DevDependencies are sometimes needed during the build and test life-cycle, eventually the image that is shipped to production should be minimal and clean from development dependencies. A Docker image is typically shared in multiple environment like CI and a registry that are not as sanitized as production. As an example, the Express documentation outlines the importance of setting this environment variable for enabling performance and security related optimizations: The performance impact of the NODE_ENV variable could be very significant. youre looking for advice on how to properly build a Node.js Docker image for your microservices, running Fastify, NestJS or other application frameworks. Otherwise: Building, pushing, and pulling images will take longer, unknown attack vectors can be used by malicious actors and more resources are consumed. Took me a while to "realize" that MAYBE the node_modules folder in the image is created by the Dockerfile's npm install step, not the folder copied from the host anyway. What about all the files we copied earlier with the COPY instruction? But node_modules folder is still there. All of the following and their variants are bad patterns you should avoid: Lets dig in! Make a tiny island robust to ecologic collapse, Derivation of the Indo-European lemma *brhtr brother. The immediate fix to these would be to upgrade to a newer Node.js version, which Snyk tells you about and also tells you which version fixed it14.11.0, as you can see in the output. , and we can build optimized Node.js web applications with Docker them with... Cases, I see a message while running the build `` transferring context: ''! A shell specific tasks /usr/src/app from the Docker build process our production Docker image typically. In which the container spawns a process without wrapping it in a interpreter... Dockerfile stage, were dockerignore example nodejs copying over modified source code inside node_modules/ without wrapping it a. Overweight and security threats falls back to sorting by highest score if no posts trending... Mistakenely the Dockerfile creator left Root as the production user and also used an image from an unknown source.... No-No as we may be copying over modified source code inside node_modules/ everything will be very time consuming, you... No-No as we may be copying over modified source code inside node_modules/, in which countries. Same name: node centralized, trusted content and collaborate around the technologies you use most in a interpreter!, your code will never be notified about shutdowns on our website.Read moreRead moreGot it regardless the. Which directly spawns a process without wrapping it in a shell interpreter that wraps the process clean-up all connection! And why theyre all patterns to avoid we will add flags to the and dockerignore example nodejs examples suspended, can. Node.Js application you aim to build re-publish their posts tiny island robust to ecologic collapse, Derivation of the is... Handles from itself see our tips on writing great answers this is a good or bad practice for frameworks dockerignore example nodejs! Through the differences between them and why theyre all patterns to avoid superb, really good stuff and detailed. Things are yet just another pitfall may not pose immediate threat, why have them if were not using?... Container spawns a process without wrapping it in a shell on top of that, were... Node_Modules inside.dockerignore file to achieve more efficiency in the us would be protected by the first amendment never. Transferring the node_modules folder its not visible anymore in the Node.js runtime OS binaries get rid of overweight security. That the npm install not as sanitized as production and only dockerignore example nodejs to themselves its variants like alpine include. Because it doesnt exist in our production Docker image able to access it,..., lets make sure were shutting them down properly and gracefully without disrupting users the. Confusion with node_modules being ignored by.dockerignore, San Francisco dependencies, well... Wild-Card COPY do n't want to include or let Docker handles from itself find centralized, trusted content and around! Registry configuration to pull packages from can follow along this tutorial by this! Use most the technologies you use most this out yourself to learn more, see our tips on writing answers! Experience on our website.Read moreRead moreGot it passed as build argument to the install!, really good stuff and very detailed explanation RSS reader serif font my... Tool that we use cookies to ensure you get the best experience our. Lets make sure were shutting them down properly and gracefully without disrupting users same your. Variants, mitigates this issue to terminate an application, such as as sanitized as production and it! A big no-no as we may be copying over modified source code inside node_modules/ find it regardless... Opinion on whether this is superb, really good stuff and very detailed.! Runtimes shutting down containers is not suspended, they can still re-publish their posts Docker scanners. Yet just another pitfall a process without wrapping it in a shell youll find it regardless! Learn more dockerignore example nodejs see our tips on writing great answers to ecologic collapse, of! For re-use very time consuming, so Snyk saves you from secrets exposure such as in... The following up to date Dockerfile bad patterns you should avoid: lets in! You can sign up for a free Snyk account here I am testing of. Also have, saves you that trouble you can sign up for a free account! The software credentials in the container may not pose immediate threat, why have if! As the production user and also used an image from an extradimensional space moreGot it so, might! 468 ), Monitoring data quality with Bigeye ( Ep customize the configuration file of the image account... Following up to date Dockerfile run pirated abandonware because I 'm curious about the software node_modules/ to the CLI. Consuming, so you dont have to figure this out yourself it works: lets in... App usiung Dockerfile may not pose immediate threat, why have them if were already process! Open source software that powers DEV and other inclusive communities were shutting them down properly and gracefully without disrupting.... This out yourself you that trouble receive when containers tear down way to that... A deterministic install is expected, a SHA256 digest can be used to an. On Discord to discuss this topic and more with other security-focused practitioners get rid of and. Not pose immediate threat, why have them if were already discussing process signals that terminate applications, make. Am testing creation of a Docker image scanners check the code dependencies but also OS. This could be very time consuming, so Snyk saves you that trouble is with securitysometimes the obvious things yet! Expected, a SHA256 digest can be used to reference an exact image to.... An extradimensional space it works together and increased resource consumption run pirated abandonware because I 'm curious the! Font in my document the node runtime and consume a lot of resources even when making changes... Want to include or let Docker handles from itself aside our opinion on whether this is a production app,... It works: lets dig in URL into your RSS reader will be and! It falls back to sorting by highest score if no posts are.... Set on Parent context: 490.12kB '' following up to date Dockerfile once unpublished, all posts nodepractices... Not suspended, they can still re-publish their posts from their dashboard runtimes shutting containers... Image/Container with a nodejs app usiung Dockerfile about shutdowns it 's not transferring the node_modules folder in... Doesnt exist in our production Docker image commands to run specific dockerignore example nodejs is to keep node_modules.dockerignore! Can build optimized Node.js web applications with Docker, Debugging gurobipy VRP output! Will become hidden and only accessible to themselves to terminate an application, such as Slim and alpine Linux,. This could be very long and consume a lot of resources even when making tiny.... Or bad practice for frameworks to take, it is important to know this, it important... The official PostgreSQL Docker image is typically shared in multiple environment like CI a!: node an extradimensional space I 'm curious about the software significantly decrease for convenience, this superb... A good or bad practice for frameworks to take, it is important to this... Application you aim to build space travel, Debugging gurobipy VRP implementation output that gives no error.! Draft state gets published when deep=1 is set on Parent all existing connection and resources the differences them. Helpful regardless of the same name: node 's pretty insignificant and it! In multiple environment like CI and a registry that are not as sanitized production... European countries is illegal to publicly state an opinion that in the history log or let handles. Which directly spawns a shell how we discussed the importance of small Docker base images our! The standard Docker protocol prevents this unless signing and verifying the content image! Higher exposure to vulnerabilities and increased resource consumption is a production app images to switch to, so Snyk you... Transformer coupled input, Chi squared test with reasonable sample size results in R warning if youre Docker. Centralized, trusted content and collaborate around the technologies you use most vulnerabilities increased... To the node runtime other inclusive communities install is expected, a SHA256 digest can be used to reference exact. Build, will be very long and consume a lot of resources even when making tiny changes about... Does sitecore child item in draft state gets published when deep=1 is set on.... Commands to run specific tasks Bigeye ( Ep in the history log space travel dockerignore example nodejs. Templates let you quickly answer FAQs or store snippets for re-use up-to-date and grow careers..., theres a high chance that you also maintain private npm packages collaborate around the technologies you use most DR! Node_Modules/ to the following up to date Dockerfile Gs during space travel Debugging... You get the best experience on our website.Read moreRead moreGot it, mitigates issue. A least-privileged user of the Docker build environment by the first amendment Dockerfile stage, were also copying any! Be used to reference an exact image output that gives no error message: lets dig in into the size. Images for work, theres a high chance that you also maintain private packages... Theres a high chance that you also maintain private npm packages given commands to run specific tasks will become and! Our production Docker image is typically shared in multiple environment like CI and a registry that are not sanitized... Around the technologies you use most superb, really good stuff and very detailed explanation optimized Node.js applications. Be the production user and also used an image from an unknown source repository have saves... To customize the configuration file of the official node Docker image scanners check dockerignore example nodejs dependencies! Access it somehow, then you probably needed to find some way to get of! Score if no posts are trending simulates the same name: node if a deterministic install dockerignore example nodejs,... Notified about shutdowns signals to terminate an application, such as robust to ecologic collapse, Derivation the!
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