Caching Dependencies - CircleCI (2022)

Caching is one of the most effective ways to make jobs faster on CircleCI. By reusing the data from previous jobs, you also reduce the cost of fetch operations. After an initial job run, subsequent instances of the job run faster, as you are not redoing work.

Caching Dependencies - CircleCI (1)

Caching is particularly useful with package dependency managers such as Yarn, Bundler, or Pip. With dependencies restored from a cache, commands like yarn install need only download new or updated dependencies, rather than downloading everything on each build.

Warning: Caching files between different executors, for example, between Docker and machine, Linux, Windows or macOS, or CircleCI image and non-CircleCI image, can result in file permissions and path errors. These errors are often caused by missing users, users with different UIDs, and missing paths. Use extra care when caching files in these cases.

Introduction

Automatic dependency caching is not available in CircleCI, so it is important to plan and implement your caching strategy to get the best performance. Manual configuration enables advanced strategies and fine-grained control. See the Caching Strategies and Persisting Data pages for tips on caching strategies and management.

This document describes the manual caching options available, the costs and benefits of a chosen strategy, and tips for avoiding problems with caching.

By default, cache storage duration is set to 15 days. This can be customized on the CircleCI web app by navigating to Plan > Usage Controls. Currently, 15 days is also the maximum storage duration you can set.

The Docker images used for CircleCI jobs are automatically cached on the server infrastructure where possible.

Warning: Although several examples are included below, caching strategies need to be carefully planned for each individual project. Copying and pasting the code examples will not always be appropriate for your needs.

For information about caching and reuse of unchanged layers of a Docker image, see the Docker Layer Caching document.

How caching works

A cache stores a hierarchy of files under a key. Use the cache to store data that makes your job faster, but, in the case of a cache miss or zero cache restore, the job still runs successfully. For example, you might cache NPM package directories (known as node_modules). The first time your job runs, it downloads all your dependencies, caches them, and (provided your cache is valid) the cache is used to speed up your job the next time it is run.

Caching is about achieving a balance between reliability and getting maximum performance. In general, it is safer to pursue reliability than to risk a corrupted build or to build very quickly using out-of-date dependencies.

Basic example of dependency caching

Saving cache

(Video) How to use caching on CircleCI

CircleCI manual dependency caching requires you to be explicit about what you cache and how you cache it. See the save cache section of the Configuring CircleCI document for additional examples.

To save a cache of a file or directory, add the save_cache step to a job in your .circleci/config.yml file:

 steps: - save_cache: key: my-cache paths: - my-file.txt - my-project/my-dependencies-directory

CircleCI imposes a 900-character limit on the length of a key. Be sure to keep your cache keys under this maximum. The path for directories is relative to the working_directory of your job. You can specify an absolute path if you choose.

Note: Unlike the special step persist_to_workspace, neither save_cache nor restore_cache support globbing for the paths key.

CircleCI restores caches in the order of keys listed in the restore_cache step. Each cache key is namespaced to the project and retrieval is prefix-matched. The cache is restored from the first matching key. If there are multiple matches, the most recently generated cache is used.

In the example below, two keys are provided:

 steps: - restore_cache: keys: # Find a cache corresponding to this specific package-lock.json checksum # when this file is changed, this key will fail - v1-npm-deps-{{ checksum "package-lock.json" }} # Find the most recently generated cache used from any branch - v1-npm-deps-

Because the second key is less specific than the first, it is more likely there will be differences between the current state and the most recently generated cache. When a dependency tool runs, it would discover outdated dependencies and update them. This is referred to as a partial cache restore.

Each line in the keys: list manages one cache (each line does not correspond to its own cache). The list of keys (v1-npm-deps-{{ checksum "package-lock.json" }} and v1-npm-deps-), in this example, represent a single cache. When it is time to restore the cache, CircleCI first validates the cache based on the first (and most specific) key, and then steps through the other keys looking for any other cache key changes.

The first key concatenates the checksum of package-lock.json file into the string v1-npm-deps-. If this file changed in your commit, CircleCI would see a new cache key.

The next key does not have a dynamic component to it. It is simply a static string: v1-npm-deps-. If you would like to invalidate your cache manually, you can bump v1 to v2 in your .circleci/config.yml file. In this case, you would now have a new cache key v2-npm-deps, which triggers the storing of a new cache.

Basic example of Yarn package manager caching

Yarn is an open-source package manager for JavaScript. The packages it installs can be cached, which can speed up builds, but, more importantly, can reduce errors related to network connectivity.

Please note, the release of Yarn 2.x comes with a the ability to do Zero Installs. If you are using Zero Installs, you should not need to do any special caching within CircleCI.

If you are using Yarn 2.x without Zero Installs, you can do something like the following:

#... - restore_cache: name: Restore Yarn Package Cache keys: - yarn-packages-{{ checksum "yarn.lock" }} - run: name: Install Dependencies command: yarn install --immutable - save_cache: name: Save Yarn Package Cache key: yarn-packages-{{ checksum "yarn.lock" }} paths: - .yarn/cache - .yarn/unplugged#...

If you are using Yarn 1.x, you can do something like the following:

#... - restore_cache: name: Restore Yarn Package Cache keys: - yarn-packages-{{ checksum "yarn.lock" }} - run: name: Install Dependencies command: yarn install --frozen-lockfile --cache-folder ~/.cache/yarn - save_cache: name: Save Yarn Package Cache key: yarn-packages-{{ checksum "yarn.lock" }} paths: - ~/.cache/yarn#...

Caching and open source

If your project is open source/available to be forked and receive PRs from contributors, make note of the following:

  • PRs from the same fork repo share a cache (this includes, as previously stated, that PRs in the main repo share a cache with main).
  • Two PRs in different fork repos have different caches.
  • Enabling the sharing of environment variables allows cache sharing between the original repo and all forked builds.

(Video) Webinar: Persisting data with Workspaces, caching, and artifacts

Caching libraries

If a job fetches data at any point, it is likely that you can make use of caching. The most important dependencies to cache during a job are the libraries on which your project depends. For example, cache the libraries that are installed with pip in Python or npm for Node.js. The various language dependency managers, for example npm or pip, each have their own paths where dependencies are installed. See our Language guides and demo projects for the specifics for your stack.

Tools that are not explicitly required for your project are best stored on the Docker image. The Docker image(s) prebuilt by CircleCI have tools preinstalled that are generic for building projects using the relevant language. For example, the cimg/ruby:3.1.2 image includes useful tools like git, openssh-client, and gzip.

Caching Dependencies - CircleCI (2)

We recommend that you verify that the dependencies installation step succeeds before adding caching steps. Caching a failed dependency step will require you to change the cache key in order to avoid failed builds due to a bad cache.

Example of caching pip dependencies:

Make note of the use of a checksum in the cache key. This is used to calculate when a specific dependency-management file (such as a package.json or requirements.txt in this case) changes, and so the cache will be updated accordingly. In the above example, the restore_cache example uses interpolation to put dynamic values into the cache-key, allowing more control in what exactly constitutes the need to update a cache.

Writing to the cache in workflows

Jobs in one workflow can share caches. This makes it possible to create race conditions in caching across different jobs in a workflow.

Cache is immutable on write. Once a cache is written for a specific key, for example, node-cache-main, it cannot be written to again.

Caching race condition example 1

Consider a workflow of 3 jobs, where Job3 depends on Job1 and Job2: {Job1, Job2} -> Job3. They all read and write to the same cache key.

In a run of the workflow, Job3 may use the cache written by Job1 or Job2. Since caches are immutable, this would be whichever job saved its cache first.

This is usually undesirable, because the results are not deterministic. Part of the result depends on chance.

You can make this workflow deterministic by changing the job dependencies. For example, make Job1 and Job2 write to different caches, and Job3 loads from only one. Or ensure there can be only one ordering: Job1 -> Job2 -> Job3.

Caching race condition example 2

There are more complex cases where jobs can save using a dynamic key like node-cache-{{ checksum "package-lock.json" }} and restore using a partial key match like node-cache-.

A race condition is still possible, but the details may change. For instance, the downstream job uses the cache from the upstream job that ran last.

Another race condition is possible when sharing caches between jobs. Consider a workflow with no dependency links: Job1 -> Job2. Job2 uses the cache saved from Job1. Job2 could sometimes successfully restore a cache, and sometimes report no cache is found, even when Job1 reports saving it. Job2 could also load a cache from a previous workflow. If this happens, this means Job2 tried to load the cache before Job1 saved it. This can be resolved by creating a workflow dependency: Job1 -> Job2. This forces Job2 to wait until Job1 has finished running.

Using caching in monorepos

There are many different approaches to utilizing caching in monorepos. The following approach can be used whenever you need to manage a shared cache based on multiple files in different parts of your monorepo.

Creating and building a concatenated package-lock file

  1. Add custom command to config:

     commands: create_concatenated_package_lock: description: "Concatenate all package-lock.json files recognized by lerna.js into single file. File is used as checksum source for part of caching key." parameters: filename: type: string steps: - run: name: Combine package-lock.json files to single file command: npx lerna la -a | awk -F packages '{printf "\"packages%s/package-lock.json\" ", $2}' | xargs cat > << parameters.filename >>
    (Video) iOS : CircleCI for iOS - caching cocoapods dependencies
  2. Use custom command in build to generate the concatenated package-lock file:

     steps: - checkout - create_concatenated_package_lock: filename: combined-package-lock.txt ## Use combined-package-lock.text in cache key - restore_cache: keys: - v3-deps-{{ checksum "package-lock.json" }}-{{ checksum "combined-package-lock.txt" }} - v3-deps

Managing caches

Clearing cache

Caches cannot be cleared. If you need to generate a new set of caches you can update the cache key, similar to the previous example. You might wish to do this if you have updated language or build management tool versions.

Updating the cache key on save and restore steps in your .circleci/config.yml file will then generate new sets of caches from that point onwards. Please note that older commits using the previous keys may still generate and save cache, so it is recommended that you rebase after the ‘config.yml’ changes when possible.

If you create a new cache by incrementing the cache version, the “older” cache is still stored. It is important to be aware that you are creating an additional cache. This method will increase your storage usage. As a general best practice, you should review what is currently being cached and reduce your storage usage as much as possible.

Tip: Caches are immutable, so it is helpful to start all your cache keys with a version prefix, for example v1-.... This allows you to regenerate all of your caches just by incrementing the version in this prefix.

For example, you may want to clear the cache in the following scenarios by incrementing the cache key name:

  • Dependency manager version change, for example, you change npm from 4 to 5.
  • Language version change, for example, you change Ruby 2.3 to 2.4.
  • Dependencies are removed from your project.

Tip: Beware when using special or reserved characters in your cache key (for example: :, ?, &, =, /, #), as they may cause issues with your build. Consider using keys within [a-z][A-Z] in your cache key prefix.

Cache size

We recommend keeping cache sizes under 500MB. This is our upper limit for corruption checks. Above this limit, check times would be excessively long. You can view the cache size from the CircleCI Jobs page within the restore_cache step. Larger cache sizes are allowed, but may cause problems due to a higher chance of decompression issues and corruption during download. To keep cache sizes down, consider splitting them into multiple distinct caches.

Viewing network and storage usage

For information on viewing your network and stoarage usage, and calculating your monthly network and storage overage costs, see the Persisting Data page.

Using keys and templates

A cache key is a user-defined string that corresponds to a data cache. A cache key can be created by interpolating dynamic values. These are called templates. Anything that appears between curly braces in a cache key is a template. Consider the following example:

myapp-{{ checksum "package-lock.json" }}
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The above example outputs a unique string to represent this key. The example is using a checksum to create a unique string that represents the contents of a package-lock.json file.

The example may output a string similar to the following:

myapp-+KlBebDceJh_zOWQIAJDLEkdkKoeldAldkaKiallQ=

If the contents of the package-lock file were to change, the checksum function would return a different, unique string, indicating the need to invalidate the cache.

When choosing suitable templates for your cache key, remember that cache saving is not a free operation. It will take some time to upload the cache to CircleCI storage. To avoid generating a new cache every build, include a key that generates a new cache only if something changes.

The first step is to decide when a cache will be saved or restored by using a key for which some value is an explicit aspect of your project. For example, when a build number increments, when a revision is incremented, or when the hash of a dependency manifest file changes.

The following are examples of caching strategies for different goals:

  • myapp-{{ checksum "package-lock.json" }} - Cache is regenerated every time something is changed in package-lock.json file. Different branches of this project generate the same cache key.
  • myapp-{{ .Branch }}-{{ checksum "package-lock.json" }} - Cache is regenerated every time something is changed in package-lock.json file. Different branches of this project generate separate cache keys.
  • myapp-{{ epoch }} - Every build generates separate cache keys.

During step execution, the templates above are replaced by runtime values and use the resultant string as the key. The following table describes the available cache key templates:

TemplateDescription
{{ checksum "filename" }}A base64 encoded SHA256 hash of the given filename’s contents, so that a new cache key is generated if the file changes. This should be a file committed in your repo. Consider using dependency manifests, such as package-lock.json, pom.xml or project.clj. The important factor is that the file does not change between restore_cache and save_cache, otherwise the cache is saved under a cache key that is different from the file used at restore_cache time.
{{ .Branch }}The VCS branch currently being built.
{{ .BuildNum }}The CircleCI job number for this build.
{{ .Revision }}The VCS revision currently being built.
{{ .Environment.variableName }}The environment variable variableName (supports any environment variable exported by CircleCI or added to a specific Context, not any arbitrary environment variable).
{{ epoch }}The number of seconds that have elapsed since 00:00:00 Coordinated Universal Time (UTC), also known as POSIX or UNIX epoch. This cache key is a good option if you need to ensure a new cache is always stored for each run.
{{ arch }}Captures OS and CPU (architecture, family, model) information. Useful when caching compiled binaries that depend on OS and CPU architecture, for example, darwin-amd64-6_58 versus linux-amd64-6_62. See supported CPU architectures.

Further notes on using keys and templates

  • A 900 character limit is imposed on each cache key. Be sure your key is shorter than this, otherwise your cache will not save.
  • When defining a unique identifier for the cache, be careful about overusing template keys that are highly specific such as {{ epoch }}. If you use less specific template keys such as {{ .Branch }} or {{ checksum "filename" }}, you increase the chance of the cache being used.
  • Cache variables can also accept parameters, if your build makes use of them. For example: v1-deps-<< parameters.varname >>.
  • You do not have to use dynamic templates for your cache key. You can use a static string, and “bump” (change) its name to force a cache invalidation.

Full example of saving and restoring cache

The following example demonstrates how to use restore_cache and save_cache, together with templates and keys in your .circleci/config.yml file.

This example uses a very specific cache key. Making your caching key more specific gives you greater control over which branch or commit dependencies are saved to a cache. However, it is important to be aware that this can significantly increase your storage usage. For tips on optimizing your caching strategy, see the Caching Strategies page.

Warning: This example is only a potential solution and might be unsuitable for your specific needs, and increase storage costs.

 docker: - image: customimage/ruby:2.3-node-phantomjs-0.0.1 auth: username: mydockerhub-user password: $DOCKERHUB_PASSWORD # context / project UI env-var reference environment: RAILS_ENV: test RACK_ENV: test - image: cimg/mysql:5.7 auth: username: mydockerhub-user password: $DOCKERHUB_PASSWORD # context / project UI env-var reference steps: - checkout - run: cp config/{database_circleci,database}.yml # Run bundler # Load installed gems from cache if possible, bundle install then save cache # Multiple caches are used to increase the chance of a cache hit - restore_cache: keys: - gem-cache-v1-{{ arch }}-{{ .Branch }}-{{ checksum "Gemfile.lock" }} - gem-cache-v1-{{ arch }}-{{ .Branch }} - gem-cache-v1 - run: bundle install --path vendor/bundle - save_cache: key: gem-cache-v1-{{ arch }}-{{ .Branch }}-{{ checksum "Gemfile.lock" }} paths: - vendor/bundle - run: bundle exec rubocop - run: bundle exec rake db:create db:schema:load --trace - run: bundle exec rake factory_girl:lint # Precompile assets # Load assets from cache if possible, precompile assets then save cache # Multiple caches are used to increase the chance of a cache hit - restore_cache: keys: - asset-cache-v1-{{ arch }}-{{ .Branch }}-{{ .Environment.CIRCLE_SHA1 }} - asset-cache-v1-{{ arch }}-{{ .Branch }} - asset-cache-v1 - run: bundle exec rake assets:precompile - save_cache: key: asset-cache-v1-{{ arch }}-{{ .Branch }}-{{ .Environment.CIRCLE_SHA1 }} paths: - public/assets - tmp/cache/assets/sprockets - run: bundle exec rspec - run: bundle exec cucumber

Source caching

It is possible and often beneficial to cache your git repository to save time in your checkout step, especially for larger projects. Here is an example of source caching:

 steps: - restore_cache: keys: - source-v1-{{ .Branch }}-{{ .Revision }} - source-v1-{{ .Branch }}- - source-v1- - checkout - save_cache: key: source-v1-{{ .Branch }}-{{ .Revision }} paths: - ".git"

In this example, restore_cache looks for a cache hit from the current git revision, then for a hit from the current branch, and finally for any cache hit, regardless of branch or revision. When CircleCI encounters a list of keys, the cache is restored from the first match. If there are multiple matches, the most recently generated cache is used.

If your source code changes frequently, we recommend using fewer, more specific keys. This produces a more granular source cache that updates more often as the current branch and git revision change.

Even with the narrowest restore_cache option (source-v1-{{ .Branch }}-{{ .Revision }}), source caching can be greatly beneficial when, for example, running repeated builds against the same git revision (for example, with API-triggered builds) or when using workflows, where you might otherwise need to checkout the same repository once per workflow job.

However, it is worth comparing build times with and without source caching. git clone is often faster than restore_cache.

NOTE: The built-in checkout command disables git’s automatic garbage collection. You might choose to manually run git gc in a run step prior to running save_cache to reduce the size of the saved cache.

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See also

  • Persisting Data
  • Caching Strategies
  • Workspaces
  • Artifacts
  • Optimizations Overview

FAQs

How does CircleCI caching work? ›

CircleCI restores caches in the order of keys listed in the restore_cache step. Each cache key is namespaced to the project and retrieval is prefix-matched. The cache is restored from the first matching key. If there are multiple matches, the most recently generated cache is used.

What is cache dependency? ›

Cache dependencies allow the application to automatically clear cached data when related objects are modified. The system uses dummy cache keys to create dependencies between cached data and other objects. Dummy keys are cache items without any data that represent objects or groups of objects.

What is artifacts vs cache? ›

Caching persists data between the same job in different Workflow builds. Artifacts persist data after a Workflow has finished.

What is a workflow CircleCI? ›

A CircleCI job is a collection of steps. All of the steps in the job are executed in a single unit, either within a fresh container, or a virtual machine. Jobs are orchestrated using workflows. The following diagram illustrates how data flows between jobs: Workspaces persist data between jobs in a single workflow.

What is Docker caching? ›

About Layer Caching in Docker

Docker uses a layer cache to optimize and speed up the process of building Docker images. Docker Layer Caching mainly works on the RUN , COPY and ADD commands, which will be explained in more detail next.

How does Docker build cache work? ›

Docker Build Cache

The concept of Docker images comes with immutable layers. Every command you execute results in a new layer that contains the changes compared to the previous layer. All previously built layers are cached and can be reused.

Which method is used to add the dependent cache item? ›

You can add an item to the application cache using the Cache object's Insert method. The method adds an item to the cache and has several overloads that enable you to add the item with different options for setting dependencies, expiration, and removal notification.

How do I speed up my GitHub actions? ›

4 ways to speed up your Github Action workflows
  1. 1 - Parallelize with multiple jobs. You should analyze your current workflow to see if you can divide it into different jobs. ...
  2. 2 - Caching dependencies. ...
  3. 3 -Select a faster runner. ...
  4. 4 -Use a strategy Matrix.
6 Jun 2021

Whats is cache? ›

In computing, a cache is a high-speed data storage layer which stores a subset of data, typically transient in nature, so that future requests for that data are served up faster than is possible by accessing the data's primary storage location.

How do I use CI cache? ›

Caching is enabled in three steps:
  1. Create a writable directory on your server where the cache files can be stored.
  2. Set the path to your cache folder in your application/config/database. php file. ...
  3. Enable the caching feature, either globally by setting the preference in your application/config/database.

How do I clear my CI cache? ›

In codeigniter, the cache is save in the folder with the path 'application/cache'. 1. Clearing all cache : You can clear the entire cache directory by calling $this->output->clear_all_cache();

Where is Pip cache stored? ›

Pip uses a caching mechanism that allows you to download and install Python packages faster. It works by storing a cache of the downloaded packages on the local wheel.

How do you run multiple commands in CircleCI? ›

In the CircleCI docs (https://circleci.com/docs/2.0/configuration-reference/#shorthand-syntax) they indicate that in using the run shorthand syntax you can also do multi-line. The difference between the question's example and this is the commands are under "run", not "command".

What is orbs in CircleCI? ›

Orbs are reusable snippets of code that help automate repeated processes, accelerate project setup, and make it easy to integrate with third-party tools. Visit the Orbs Registry on the CircleCI Developer Hub to search for orbs to help simplify your configuration.

How do you run a CircleCI pipeline? ›

Instead of using the API, you can set up scheduled pipelines from right in the CircleCI dashboard. From your project in CircleCI, go to Project Settings, and select Triggers from the menu on the left. Click Add Scheduled Trigger to open the page where you can set up a new scheduled pipeline.

Where is docker cache stored? ›

In a default install, these are located in /var/lib/docker. During a new build, all of these file structures have to be created and written to disk — this is where Docker stores base images.

How do I create a docker cache? ›

About the Docker Build Cache

Docker images are built in layers, where each layer is an instruction from a Dockerfile. Layers stack on top of each other, adding functionality incrementally. The build process knew the Dockerfile didn't change, so it used the cache from the last build for all four layers.

Does Jenkins cache docker images? ›

Still the bottom line is: Jenkins does not cache automagically for you. Caching is inside the scope of the build tool(s) that you are using. You have to take care to incorporate that properly to your CI environment's needs. But of course it is possible to achieve.

How do I delete all docker cache? ›

Cleaning local docker cache
  1. docker system df.
  2. docker ps --filter status=exited --filter status=dead -q.
  3. docker rm $(docker ps --filter=status=exited --filter=status=dead -q)
  4. docker container prune.
  5. docker ps -q.
  6. docker stop $(docker ps -q)
  7. docker rm $(docker ps -a -q)
  8. docker images --filter dangling=true -q.
2 Jun 2021

How do I clean my docker container? ›

Procedure
  1. Stop the container(s) using the following command: docker-compose down.
  2. Delete all containers using the following command: docker rm -f $(docker ps -a -q)
  3. Delete all volumes using the following command: docker volume rm $(docker volume ls -q)
  4. Restart the containers using the following command:

Where are container images stored? ›

If you use the default storage driver overlay2, then your Docker images are stored in /var/lib/docker/overlay2 . There, you can find different files that represent read-only layers of a Docker image and a layer on top of it that contains your changes.

Which of the following ASP.NET caching dependencies can be made to be dependent on a row in a table in SQL server? ›

ASP.NET allows you to use the SqlCacheDependency class to create a cache item dependency on a table or row in a database.

How does sliding expiration work? ›

Sliding expiration resets the expiration time for a valid authentication cookie if a request is made and more than half of the timeout interval has elapsed. If the cookie expires, the user must re-authenticate.

Where is ASP.NET cache stored? ›

Cache is stored in web server memory.

How long does GitHub Actions cache last? ›

Get GitHub Actions cache usage for an organization

Gets the total GitHub Actions cache usage for an organization. The data fetched using this API is refreshed approximately every 5 minutes, so values returned from this endpoint may take at least 5 minutes to get updated.

How can I speed up my workflow? ›

10 Tricks to Speed Up Your Workflow
  1. Analyze Your Current Process. ...
  2. Reduce Your Workflow Complexity. ...
  3. Strive to Make Tasks Simpler. ...
  4. Move Past Multitasking. ...
  5. Feng Shui Your Workspace. ...
  6. Minimize Work Interruptions. ...
  7. Optimize Team Communications. ...
  8. Streamline Your Collaboration.
16 Nov 2021

How does caching work in GitHub Actions? ›

Example using the cache action

The cache key uses contexts and expressions to generate a key that includes the runner's operating system and a SHA-256 hash of the package-lock. json file. When key matches an existing cache, it's called a cache hit, and the action restores the cached files to the path directory.

What is caching and how it works? ›

Cached data works by storing data for re-access in a device's memory. The data is stored high up in a computer's memory just below the central processing unit (CPU).

What are the different types of caching? ›

There are four major caching types used in web development. We will learn about each of these caches in the next set of cards.
  • Web Caching (Browser/Proxy/Gateway)
  • Data Caching.
  • Application/Output Caching.
  • Distributed Caching.

What is API caching? ›

The Cache API is a system for storing and retrieving network requests and their corresponding responses. These might be regular requests and responses created in the course of running your application, or they could be created solely for the purpose of storing data for later use.

What is cache in Gitlab CI? ›

Caching in GitLab CI/CD (FREE) A cache is one or more files that a job downloads and saves. Subsequent jobs that use the same cache don't have to download the files again, so they execute more quickly.

Where is Gitlab CI cache stored? ›

By default, they are stored locally in the machine where the Runner is installed and depends on the type of the executor. Locally, stored under the gitlab-runner user's home directory: /home/gitlab-runner/cache/<user>/<project>/<cache-key>/cache. zip .

Where does yarn cache packages? ›

Yarn stores every package in a global cache in your user directory on the file system. yarn cache list will print out every cached package.

What is Before_script in Gitlab CI? ›

These are scripts that you choose to be run before the job is executed or after the job is executed. These can also be defined at the top level of the YAML file (where jobs are defined) and they'll apply to all jobs in the . gitlab-ci. yml file.

Does pip cache clear? ›

If you want to force pip to clear out its download cache and use the specific version you can do by using --no-cache-dir command. If you are using an older version of pip than upgrade it with pip install -U pip. This will help you clear pip cache.

What does pip cache do? ›

pip provides an on-by-default caching, designed to reduce the amount of time spent on duplicate downloads and builds.

Can I delete pip cache directory? ›

It is safe to delete the user cache directory. It will simply cause pip to re-download all packages from PyPI.

What is parallelism in CircleCI? ›

circleci/config. yml file. The parallelism key specifies how many independent executors are set up to run the steps. To run a job's steps in parallel, set the parallelism key to a value greater than 1.

What is context in CircleCI? ›

Contexts provide a mechanism for securing and sharing environment variables across projects. The environment variables are defined as name/value pairs and are injected at runtime. This document describes creating and using contexts in CircleCI.

Is CircleCI open source? ›

CircleCI Orbs

The Orbs are housed in an open source code library.

How do I create an orb in CircleCI? ›

Getting started
  1. Create a new empty GitHub repository . ...
  2. Update the CircleCI CLI. ...
  3. Initialize your orb. ...
  4. Choose the fully automated orb setup option. ...
  5. Follow the prompts to configure and set up your orb. ...
  6. Ensure the context is restricted. ...
  7. Push the changes up to Github. ...
  8. Complete the setup.

Is an eye an orb? ›

1. An organ of vision: eye.

Is CircleCI better than Jenkins? ›

In conclusion, the key difference between CircleCI vs Jenkins is that Jenkins is more secure and elaborates; CircleCI is lightweight and open. Therefore for faster deployment jobs, one can execute their codes on CircleCI as it deploys on scalable and robust cloud servers.

Is CircleCI CI CD? ›

CI/CD built for performance:

Customizable RAM and CPU for different jobs. Workflows to help manage job orchestration. Parallelism to maximize build efficiency. SSH access into failed builds for easy debugging.

How do I trigger a CircleCI job? ›

Trigger a pipeline from the CircleCI web app

Select your branch using the branch filter at the top of the dashboard. Click Trigger Pipeline. At this point you can choose whether you want to specify any pipeline parameters. Click Trigger Pipeline again (or Cancel) and you will see your new pipeline start.

Where are Docker images cached? ›

In a default install, these are located in /var/lib/docker. During a new build, all of these file structures have to be created and written to disk — this is where Docker stores base images. Once created, the container (and subsequent new ones) will be stored in the folder in this same area.

Where does yarn cache packages? ›

Yarn stores every package in a global cache in your user directory on the file system. yarn cache list will print out every cached package.

Does Jenkins cache Docker images? ›

Still the bottom line is: Jenkins does not cache automagically for you. Caching is inside the scope of the build tool(s) that you are using. You have to take care to incorporate that properly to your CI environment's needs. But of course it is possible to achieve.

How do you use cache? ›

How does Caching work? The data in a cache is generally stored in fast access hardware such as RAM (Random-access memory) and may also be used in correlation with a software component. A cache's primary purpose is to increase data retrieval performance by reducing the need to access the underlying slower storage layer.

Does docker pull cache? ›

Pulling cached images

After you configure the Docker daemon to use the Container Registry cache, Docker performs the following steps when you pull a public Docker Hub image with a docker pull command: The Docker daemon checks the Container Registry cache and fetches the images if it exists.

How do I create a docker cache? ›

About the Docker Build Cache

Docker images are built in layers, where each layer is an instruction from a Dockerfile. Layers stack on top of each other, adding functionality incrementally. The build process knew the Dockerfile didn't change, so it used the cache from the last build for all four layers.

How do I remove cached images from docker? ›

  1. Clear images cache. You can use the command docker image prune to delete all dangling and intermediate images: ...
  2. Clear stopped containers. ...
  3. Clear unused networks. ...
  4. Clear unused local volumes. ...
  5. Clear all Docker unused objects (images, containers, networks, local volumes)

What is yarn cache for? ›

Yarn creates a cached copy which facilitates offline package installs. Therefore you can install your npm packages without an internet connection with Yarn.

Can I delete library caches yarn? ›

If you want to remove a specific lib's cache run $ yarn cache dir to get the right yarn cache directory path for your OS, then $ cd to that directory and remove the folder with the name + version of the lib you want to cleanup.

Can we delete yarn cache? ›

To clear a cache in yarn, we need to run the yarn cache clean command in our terminal. This above command deletes all data from your cache directory. If you want clear a cache for the particular package or module, you can do it like this. If you want to print out every cached package that stores in your ~/.

Does Jenkins have cache? ›

Jenkins will caches the data again as you executed the builds depending upon the repositories used in those build by leveraging config. xml file of each job.

How do Docker and Jenkins work together? ›

Jenkins builds a new docker image and pushes it to the Docker registry. Jenkins notifies Kubernetes of the new image available for deployment. Kubernetes pulls the new docker image from the docker registry. Kubernetes deploys and manages the docker instance/container.

What is caching in API? ›

The Cache API is a system for storing and retrieving network requests and their corresponding responses. These might be regular requests and responses created in the course of running your application, or they could be created solely for the purpose of storing data for later use.

What are the different types of caching? ›

There are four major caching types used in web development. We will learn about each of these caches in the next set of cards.
  • Web Caching (Browser/Proxy/Gateway)
  • Data Caching.
  • Application/Output Caching.
  • Distributed Caching.

When should one not use cache? ›

Three caching challenges to consider

Caches take up space on the disk, so we have to assess whether the time we are saving is worth the amount of disk space used. Cached data might not be the most accurate, particularly for volatile real-time data. Therefore, volatile data should not be cached.

Videos

1. Webinar: Introduction to .circleci/config.yml
(CircleCI)
2. CircleCI Orb Example
(Ryan Kienstra)
3. Improve Visibility into your Pipelines with CircleCI’s New Insights Endpoints
(CircleCI)
4. "Accelerating Continuous Integration by Caching Environments and Inferring Dependencies" at FSE 2021
(Keheliya Gallaba)
5. Automate your Software Development with Docker and CircleCI
(CircleCI)
6. Set up faster, easier, end-to-end testing with CircleCI and Cypress
(CircleCI)

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