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crazylion lee

Real Artists Ship - Native Issue Tracking - 1 views

  •  
    "Ship is a new take on issue tracking for software projects with a focus on SPEED!"
crazylion lee

Riemann - A network monitoring system - 0 views

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    "Riemann aggregates events from your servers and applications with a powerful stream processing language. Send an email for every exception in your app. Track the latency distribution of your web app. See the top processes on any host, by memory and CPU. Combine statistics from every Riak node in your cluster and forward to Graphite. Track user activity from second to second."
crazylion lee

Social Media Sharing Buttons. No JavaScript. No tracking. Super fast and easy. - 0 views

  •  
    "Super fast and easy Social Media Sharing Buttons. No JavaScript. No tracking."
張 旭

The Twelve-Factor App - 0 views

  • A copy of the revision tracking database is known as a code repository, often shortened to code repo or just repo.
  • always a one-to-one correlation between the codebase and the app
  • If there are multiple codebases, it’s not an app – it’s a distributed system.
  • ...4 more annotations...
  • Each component in a distributed system is an app
  • only one codebase per app, but there will be many deploys of the app.
  • A deploy is a running instance of the app.
  • The codebase is the same across all deploys, although different versions may be active in each deploy.
  •  
    "A copy of the revision tracking database is known as a code repository, often shortened to code repo or just repo."
crazylion lee

GitHub - dianping/cat: Central Application Tracking - 0 views

shared by crazylion lee on 15 Mar 18 - No Cached
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    "Central Application Tracking"
crazylion lee

Home Assistant - 1 views

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    "Home Assistant is an open-source home automation platform running on Python 3. Track and control all devices at home and automate control. Installation in less than a minute. "
張 旭

Helm | - 0 views

  • A chart is a collection of files that describe a related set of Kubernetes resources.
  • A single chart might be used to deploy something simple, like a memcached pod, or something complex, like a full web app stack with HTTP servers, databases, caches, and so on.
  • Charts are created as files laid out in a particular directory tree, then they can be packaged into versioned archives to be deployed.
  • ...170 more annotations...
  • A chart is organized as a collection of files inside of a directory.
  • values.yaml # The default configuration values for this chart
  • charts/ # A directory containing any charts upon which this chart depends.
  • templates/ # A directory of templates that, when combined with values, # will generate valid Kubernetes manifest files.
  • version: A SemVer 2 version (required)
  • apiVersion: The chart API version, always "v1" (required)
  • Every chart must have a version number. A version must follow the SemVer 2 standard.
  • non-SemVer names are explicitly disallowed by the system.
  • When generating a package, the helm package command will use the version that it finds in the Chart.yaml as a token in the package name.
  • the appVersion field is not related to the version field. It is a way of specifying the version of the application.
  • appVersion: The version of the app that this contains (optional). This needn't be SemVer.
  • If the latest version of a chart in the repository is marked as deprecated, then the chart as a whole is considered to be deprecated.
  • deprecated: Whether this chart is deprecated (optional, boolean)
  • one chart may depend on any number of other charts.
  • dependencies can be dynamically linked through the requirements.yaml file or brought in to the charts/ directory and managed manually.
  • the preferred method of declaring dependencies is by using a requirements.yaml file inside of your chart.
  • A requirements.yaml file is a simple file for listing your dependencies.
  • The repository field is the full URL to the chart repository.
  • you must also use helm repo add to add that repo locally.
  • helm dependency update and it will use your dependency file to download all the specified charts into your charts/ directory for you.
  • When helm dependency update retrieves charts, it will store them as chart archives in the charts/ directory.
  • Managing charts with requirements.yaml is a good way to easily keep charts updated, and also share requirements information throughout a team.
  • All charts are loaded by default.
  • The condition field holds one or more YAML paths (delimited by commas). If this path exists in the top parent’s values and resolves to a boolean value, the chart will be enabled or disabled based on that boolean value.
  • The tags field is a YAML list of labels to associate with this chart.
  • all charts with tags can be enabled or disabled by specifying the tag and a boolean value.
  • The --set parameter can be used as usual to alter tag and condition values.
  • Conditions (when set in values) always override tags.
  • The first condition path that exists wins and subsequent ones for that chart are ignored.
  • The keys containing the values to be imported can be specified in the parent chart’s requirements.yaml file using a YAML list. Each item in the list is a key which is imported from the child chart’s exports field.
  • specifying the key data in our import list, Helm looks in the exports field of the child chart for data key and imports its contents.
  • the parent key data is not contained in the parent’s final values. If you need to specify the parent key, use the ‘child-parent’ format.
  • To access values that are not contained in the exports key of the child chart’s values, you will need to specify the source key of the values to be imported (child) and the destination path in the parent chart’s values (parent).
  • To drop a dependency into your charts/ directory, use the helm fetch command
  • A dependency can be either a chart archive (foo-1.2.3.tgz) or an unpacked chart directory.
  • name cannot start with _ or .. Such files are ignored by the chart loader.
  • a single release is created with all the objects for the chart and its dependencies.
  • Helm Chart templates are written in the Go template language, with the addition of 50 or so add-on template functions from the Sprig library and a few other specialized functions
  • When Helm renders the charts, it will pass every file in that directory through the template engine.
  • Chart developers may supply a file called values.yaml inside of a chart. This file can contain default values.
  • Chart users may supply a YAML file that contains values. This can be provided on the command line with helm install.
  • When a user supplies custom values, these values will override the values in the chart’s values.yaml file.
  • Template files follow the standard conventions for writing Go templates
  • {{default "minio" .Values.storage}}
  • Values that are supplied via a values.yaml file (or via the --set flag) are accessible from the .Values object in a template.
  • pre-defined, are available to every template, and cannot be overridden
  • the names are case sensitive
  • Release.Name: The name of the release (not the chart)
  • Release.IsUpgrade: This is set to true if the current operation is an upgrade or rollback.
  • Release.Revision: The revision number. It begins at 1, and increments with each helm upgrade
  • Chart: The contents of the Chart.yaml
  • Files: A map-like object containing all non-special files in the chart.
  • Files can be accessed using {{index .Files "file.name"}} or using the {{.Files.Get name}} or {{.Files.GetString name}} functions.
  • .helmignore
  • access the contents of the file as []byte using {{.Files.GetBytes}}
  • Any unknown Chart.yaml fields will be dropped
  • Chart.yaml cannot be used to pass arbitrarily structured data into the template.
  • A values file is formatted in YAML.
  • A chart may include a default values.yaml file
  • be merged into the default values file.
  • The default values file included inside of a chart must be named values.yaml
  • accessible inside of templates using the .Values object
  • Values files can declare values for the top-level chart, as well as for any of the charts that are included in that chart’s charts/ directory.
  • Charts at a higher level have access to all of the variables defined beneath.
  • lower level charts cannot access things in parent charts
  • Values are namespaced, but namespaces are pruned.
  • the scope of the values has been reduced and the namespace prefix removed
  • Helm supports special “global” value.
  • a way of sharing one top-level variable with all subcharts, which is useful for things like setting metadata properties like labels.
  • If a subchart declares a global variable, that global will be passed downward (to the subchart’s subcharts), but not upward to the parent chart.
  • global variables of parent charts take precedence over the global variables from subcharts.
  • helm lint
  • A chart repository is an HTTP server that houses one or more packaged charts
  • Any HTTP server that can serve YAML files and tar files and can answer GET requests can be used as a repository server.
  • Helm does not provide tools for uploading charts to remote repository servers.
  • the only way to add a chart to $HELM_HOME/starters is to manually copy it there.
  • Helm provides a hook mechanism to allow chart developers to intervene at certain points in a release’s life cycle.
  • Execute a Job to back up a database before installing a new chart, and then execute a second job after the upgrade in order to restore data.
  • Hooks are declared as an annotation in the metadata section of a manifest
  • Hooks work like regular templates, but they have special annotations
  • pre-install
  • post-install: Executes after all resources are loaded into Kubernetes
  • pre-delete
  • post-delete: Executes on a deletion request after all of the release’s resources have been deleted.
  • pre-upgrade
  • post-upgrade
  • pre-rollback
  • post-rollback: Executes on a rollback request after all resources have been modified.
  • crd-install
  • test-success: Executes when running helm test and expects the pod to return successfully (return code == 0).
  • test-failure: Executes when running helm test and expects the pod to fail (return code != 0).
  • Hooks allow you, the chart developer, an opportunity to perform operations at strategic points in a release lifecycle
  • Tiller then loads the hook with the lowest weight first (negative to positive)
  • Tiller returns the release name (and other data) to the client
  • If the resources is a Job kind, Tiller will wait until the job successfully runs to completion.
  • if the job fails, the release will fail. This is a blocking operation, so the Helm client will pause while the Job is run.
  • If they have hook weights (see below), they are executed in weighted order. Otherwise, ordering is not guaranteed.
  • good practice to add a hook weight, and set it to 0 if weight is not important.
  • The resources that a hook creates are not tracked or managed as part of the release.
  • leave the hook resource alone.
  • To destroy such resources, you need to either write code to perform this operation in a pre-delete or post-delete hook or add "helm.sh/hook-delete-policy" annotation to the hook template file.
  • Hooks are just Kubernetes manifest files with special annotations in the metadata section
  • One resource can implement multiple hooks
  • no limit to the number of different resources that may implement a given hook.
  • When subcharts declare hooks, those are also evaluated. There is no way for a top-level chart to disable the hooks declared by subcharts.
  • Hook weights can be positive or negative numbers but must be represented as strings.
  • sort those hooks in ascending order.
  • Hook deletion policies
  • "before-hook-creation" specifies Tiller should delete the previous hook before the new hook is launched.
  • By default Tiller will wait for 60 seconds for a deleted hook to no longer exist in the API server before timing out.
  • Custom Resource Definitions (CRDs) are a special kind in Kubernetes.
  • The crd-install hook is executed very early during an installation, before the rest of the manifests are verified.
  • A common reason why the hook resource might already exist is that it was not deleted following use on a previous install/upgrade.
  • Helm uses Go templates for templating your resource files.
  • two special template functions: include and required
  • include function allows you to bring in another template, and then pass the results to other template functions.
  • The required function allows you to declare a particular values entry as required for template rendering.
  • If the value is empty, the template rendering will fail with a user submitted error message.
  • When you are working with string data, you are always safer quoting the strings than leaving them as bare words
  • Quote Strings, Don’t Quote Integers
  • when working with integers do not quote the values
  • env variables values which are expected to be string
  • to include a template, and then perform an operation on that template’s output, Helm has a special include function
  • The above includes a template called toYaml, passes it $value, and then passes the output of that template to the nindent function.
  • Go provides a way for setting template options to control behavior when a map is indexed with a key that’s not present in the map
  • The required function gives developers the ability to declare a value entry as required for template rendering.
  • The tpl function allows developers to evaluate strings as templates inside a template.
  • Rendering a external configuration file
  • (.Files.Get "conf/app.conf")
  • Image pull secrets are essentially a combination of registry, username, and password.
  • Automatically Roll Deployments When ConfigMaps or Secrets change
  • configmaps or secrets are injected as configuration files in containers
  • a restart may be required should those be updated with a subsequent helm upgrade
  • The sha256sum function can be used to ensure a deployment’s annotation section is updated if another file changes
  • checksum/config: {{ include (print $.Template.BasePath "/configmap.yaml") . | sha256sum }}
  • helm upgrade --recreate-pods
  • "helm.sh/resource-policy": keep
  • resources that should not be deleted when Helm runs a helm delete
  • this resource becomes orphaned. Helm will no longer manage it in any way.
  • create some reusable parts in your chart
  • In the templates/ directory, any file that begins with an underscore(_) is not expected to output a Kubernetes manifest file.
  • by convention, helper templates and partials are placed in a _helpers.tpl file.
  • The current best practice for composing a complex application from discrete parts is to create a top-level umbrella chart that exposes the global configurations, and then use the charts/ subdirectory to embed each of the components.
  • SAP’s Converged charts: These charts install SAP Converged Cloud a full OpenStack IaaS on Kubernetes. All of the charts are collected together in one GitHub repository, except for a few submodules.
  • Deis’s Workflow: This chart exposes the entire Deis PaaS system with one chart. But it’s different from the SAP chart in that this umbrella chart is built from each component, and each component is tracked in a different Git repository.
  • YAML is a superset of JSON
  • any valid JSON structure ought to be valid in YAML.
  • As a best practice, templates should follow a YAML-like syntax unless the JSON syntax substantially reduces the risk of a formatting issue.
  • There are functions in Helm that allow you to generate random data, cryptographic keys, and so on.
  • a chart repository is a location where packaged charts can be stored and shared.
  • A chart repository is an HTTP server that houses an index.yaml file and optionally some packaged charts.
  • Because a chart repository can be any HTTP server that can serve YAML and tar files and can answer GET requests, you have a plethora of options when it comes down to hosting your own chart repository.
  • It is not required that a chart package be located on the same server as the index.yaml file.
  • A valid chart repository must have an index file. The index file contains information about each chart in the chart repository.
  • The Helm project provides an open-source Helm repository server called ChartMuseum that you can host yourself.
  • $ helm repo index fantastic-charts --url https://fantastic-charts.storage.googleapis.com
  • A repository will not be added if it does not contain a valid index.yaml
  • add the repository to their helm client via the helm repo add [NAME] [URL] command with any name they would like to use to reference the repository.
  • Helm has provenance tools which help chart users verify the integrity and origin of a package.
  • Integrity is established by comparing a chart to a provenance record
  • The provenance file contains a chart’s YAML file plus several pieces of verification information
  • Chart repositories serve as a centralized collection of Helm charts.
  • Chart repositories must make it possible to serve provenance files over HTTP via a specific request, and must make them available at the same URI path as the chart.
  • We don’t want to be “the certificate authority” for all chart signers. Instead, we strongly favor a decentralized model, which is part of the reason we chose OpenPGP as our foundational technology.
  • The Keybase platform provides a public centralized repository for trust information.
  • A chart contains a number of Kubernetes resources and components that work together.
  • A test in a helm chart lives under the templates/ directory and is a pod definition that specifies a container with a given command to run.
  • The pod definition must contain one of the helm test hook annotations: helm.sh/hook: test-success or helm.sh/hook: test-failure
  • helm test
  • nest your test suite under a tests/ directory like <chart-name>/templates/tests/
crazylion lee

Little Snitch - 1 views

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    "As soon as you're connected to the Internet, applications can potentially send whatever they want to wherever they want. Most often they do this to your benefit. But sometimes, like in case of tracking software, trojans or other malware, they don't. But you don't notice anything, because all of this happens invisibly under the hood."
張 旭

Dependency Lock File (.terraform.lock.hcl) - Configuration Language | Terraform | Hashi... - 0 views

  • Version constraints within the configuration itself determine which versions of dependencies are potentially compatible, but after selecting a specific version of each dependency Terraform remembers the decisions it made in a dependency lock file
  • At present, the dependency lock file tracks only provider dependencies.
  • Terraform does not remember version selections for remote modules, and so Terraform will always select the newest available module version that meets the specified version constraints.
  • ...14 more annotations...
  • The lock file is always named .terraform.lock.hcl, and this name is intended to signify that it is a lock file for various items that Terraform caches in the .terraform
  • Terraform automatically creates or updates the dependency lock file each time you run the terraform init command.
  • You should include this file in your version control repository
  • If a particular provider has no existing recorded selection, Terraform will select the newest available version that matches the given version constraint, and then update the lock file to include that selection.
  • the "trust on first use" model
  • you can pre-populate checksums for a variety of different platforms in your lock file using the terraform providers lock command, which will then allow future calls to terraform init to verify that the packages available in your chosen mirror match the official packages from the provider's origin registry.
  • The h1: and zh: prefixes on these values represent different hashing schemes, each of which represents calculating a checksum using a different algorithm.
  • zh:: a mnemonic for "zip hash"
  • h1:: a mnemonic for "hash scheme 1", which is the current preferred hashing scheme.
  • To determine whether there still exists a dependency on a given provider, Terraform uses two sources of truth: the configuration itself, and the state.
  • Version constraints within the configuration itself determine which versions of dependencies are potentially compatible, but after selecting a specific version of each dependency Terraform remembers the decisions it made in a dependency lock file so that it can (by default) make the same decisions again in future.
  • At present, the dependency lock file tracks only provider dependencies.
  • Terraform will always select the newest available module version that meets the specified version constraints.
  • The lock file is always named .terraform.lock.hcl
  •  
    "the overriding effect is compounded, with later blocks taking precedence over earlier blocks."
crazylion lee

Noiszy - 0 views

張 旭

Getting Started with Docker - Servers for Hackers - 0 views

  • Docker is an isolated portion of the host computer, sharing the host kernel (OS) and even its bin/libraries if appropriate.
  • the Docker Container contains the parts that make Ubuntu different from CoreOS.
  • A Docker container only stays alive as long as there is an active process being run in it.
  • ...10 more annotations...
  • Allocate a (pseudo) tty
  • Keep stdin open (so we can interact with it)
  • Docker allows us make changes to an image, commit those changes, and then push those changes out somehwere.
  • Docker tracks any changes we make to a container
  • The Dockerfile provides a set of instructions for Docker to run on a container.
  • what image (and tag in this case) to base this off of
  • run the given command (as user "root")
  • copy a file from the host machine into the container
  • expose a port to the host machine. You can expose multiple ports
  • run a command
張 旭

The Rails Command Line - Ruby on Rails Guides - 0 views

  • rake --tasks
  • Think of destroy as the opposite of generate.
  • runner runs Ruby code in the context of Rails non-interactively
  • ...28 more annotations...
  • rails dbconsole figures out which database you're using and drops you into whichever command line interface you would use with it
  • The console command lets you interact with your Rails application from the command line. On the underside, rails console uses IRB
  • rake about gives information about version numbers for Ruby, RubyGems, Rails, the Rails subcomponents, your application's folder, the current Rails environment name, your app's database adapter, and schema version
  • You can precompile the assets in app/assets using rake assets:precompile and remove those compiled assets using rake assets:clean.
  • rake db:version is useful when troubleshooting
  • The doc: namespace has the tools to generate documentation for your app, API documentation, guides.
  • rake notes will search through your code for comments beginning with FIXME, OPTIMIZE or TODO.
  • You can also use custom annotations in your code and list them using rake notes:custom by specifying the annotation using an environment variable ANNOTATION.
  • rake routes will list all of your defined routes, which is useful for tracking down routing problems in your app, or giving you a good overview of the URLs in an app you're trying to get familiar with.
  • rake secret will give you a pseudo-random key to use for your session secret.
  • Custom rake tasks have a .rake extension and are placed in Rails.root/lib/tasks.
  • rails new . --git --database=postgresql
  • All commands can run with -h or --help to list more information
  • The rails server command launches a small web server named WEBrick which comes bundled with Ruby
  • rails server -e production -p 4000
  • You can run a server as a daemon by passing a -d option
  • The rails generate command uses templates to create a whole lot of things.
  • Using generators will save you a large amount of time by writing boilerplate code, code that is necessary for the app to work.
  • All Rails console utilities have help text.
  • generate controller ControllerName action1 action2.
  • With a normal, plain-old Rails application, your URLs will generally follow the pattern of http://(host)/(controller)/(action), and a URL like http://(host)/(controller) will hit the index action of that controller.
  • A scaffold in Rails is a full set of model, database migration for that model, controller to manipulate it, views to view and manipulate the data, and a test suite for each of the above.
  • Unit tests are code that tests and makes assertions about code.
  • Unit tests are your friend.
  • rails console --sandbox
  • rails db
  • Each task has a description, and should help you find the thing you need.
  • rake tmp:clear clears all the three: cache, sessions and sockets.
張 旭

Asset Pipeline - Ruby on Rails 指南 - 0 views

  • 清单文件或帮助方法
    • 張 旭
       
      清單文件是指:application.css 跟 application.js
  • Sprockets 会按照搜索路径中各路径出现的顺序进行搜索。默认情况下,这意味着 app/assets 文件夹中的静态资源优先级较高,会遮盖 lib 和 vendor 文件夹中的相应文件
  • 如果静态资源不会在清单文件中引入,就要添加到预编译的文件列表中,否则在生产环境中就无法访问文件。
  • ...36 more annotations...
  • 程序中使用了 jQuery 代码库和许多模块,都保存在 lib/assets/javascripts/library_name 文件夹中,那么 lib/assets/javascripts/library_name/index.js 文件的作用就是这个代码库的清单。清单文件中可以按顺序列出所需的文件,或者干脆使用 require_tree 指令。
  • 如果使用 Turbolinks(Rails 4 默认启用),加上 data-turbolinks-track 选项后,Turbolinks 会检查静态资源是否有更新,如果更新了就会将其载入页面
  • config.assets.paths 包含标准路径和其他 Rails 引擎添加的路径。
  • 链接不存在的资源(也包括链接到空字符串的情况)会在调用页面抛出异常。
  • 关闭标签不能使用 -%> 形式
  • Sprockets 通过清单文件决定要引入和伺服哪些静态资源
  • 在 JavaScript 文件中,Sprockets 的指令以 //= 开头。在上面的文件中,用到了 require 和 the require_tree 指令。
  • app/assets/javascripts/application.js
  • require_tree 指令告知 Sprockets 递归引入指定文件夹中的所有 JavaScript 文件。文件夹的路径必须相对于清单文件。也可使用 require_directory 指令加载指定文件夹中的所有 JavaScript 文件,但不会递归。
  • Sprockets 会按照从上至下的顺序处理指令,但 require_tree 引入的文件顺序是不可预期的,不要设想能得到一个期望的顺序。
  • app/assets/stylesheets/application.css
  • 不管创建新程序时有没有指定 --skip-sprockets 选项,Rails 4 都会生成 app/assets/javascripts/application.js 和 app/assets/stylesheets/application.css
  • 如果多次调用 require_self,只有最后一次调用有效
  • 如果想使用多个 Sass 文件,应该使用 Sass 中的 @import 规则,不要使用 Sprockets 指令。
  • 清单文件可以有多个。
  • 如果使用默认的 gem,生成控制器或脚手架时,会生成 CoffeeScript 和 SCSS 文件,而不是普通的 JavaScript 和 CSS 文件。
  • 在开发环境中,或者禁用 Asset Pipeline 时,这些文件会使用 coffee-script 和 sass 提供的预处理器处理,然后再发给浏览器
  • 启用 Asset Pipeline 时,这些文件会先使用预处理器处理,然后保存到 public/assets 文件夹中,再由 Rails 程序或网页服务器伺服
  • 添加额外的扩展名可以增加预处理次数,预处理程序会按照扩展名从右至左的顺序处理文件内容。所以,扩展名的顺序要和处理的顺序一致
  • 预处理器的执行顺序很重要
  • 在开发环境中也可启用压缩功能,检查是否能正常运行。需要调试时再禁用压缩即可。
  • 默认情况下,Rails 认为静态资源已经事先编译好了,直接由网页服务器伺服。
  • 般情况下,请勿修改 config.assets.digest 的默认值
  • 可在部署时编译静态资源
  • 在多次部署之间共用这个文件夹是十分重要的,这样只要缓存的页面可用,其中引用的编译后的静态资源就能正常使用。
  • 默认编译的文件包括 application.js、application.css 以及 gem 中 app/assets 文件夹中的所有非 JS/CSS 文件(会自动加载所有图片)
  • 如果想编译其他清单,或者单独的样式表和 JavaScript,可以添加到 config/application.rb 文件中的 precompile 选项
  • 设置编译所有静态资源
  • manifest-md5hash.json 的文件,列出所有静态资源和对应的指纹
  • 把 Expires 报头设置为很久以后
  • 在本地预编译后,可以把编译好的文件纳入版本控制系统,再按照常规的方式部署
  • 实时编译消耗的内存更多,比默认的编译方式性能更低,因此不推荐使用
  • 如果用 CDN 分发静态资源,要确保文件不会被缓存,因为缓存会导致问题。如果设置了 config.action_controller.perform_caching = true,Rack::Cache 会使用 Rails.cache 存储静态文件,很快缓存空间就会用完。
  • Sprockets 默认使用的公开路径是 /assets
  • X-Sendfile 报头的作用是让服务器忽略程序的响应,直接从硬盘上伺服指定的文件
  • 为 Rails 提供标准 JavaScript 代码库的 jquery-rails gem 是个很好的例子。这个 gem 中有个引擎类,继承自 Rails::Engine。添加这层继承关系后,Rails 就知道这个 gem 中可能包含静态资源文件,会把这个引擎中的 app/assets、lib/assets 和 vendor/assets 三个文件夹加入 Sprockets 的搜索路径中。
張 旭

Getting Started with Rails - Ruby on Rails Guides - 0 views

  • A controller's purpose is to receive specific requests for the application.
  • Routing decides which controller receives which requests
  • The view should just display that information
  • ...55 more annotations...
  • view templates are written in a language called ERB (Embedded Ruby) which is converted by the request cycle in Rails before being sent to the user.
  • Each action's purpose is to collect information to provide it to a view.
  • A view's purpose is to display this information in a human readable format.
  • routing file which holds entries in a special DSL (domain-specific language) that tells Rails how to connect incoming requests to controllers and actions.
  • You can create, read, update and destroy items for a resource and these operations are referred to as CRUD operations
  • A controller is simply a class that is defined to inherit from ApplicationController.
  • If not found, then it will attempt to load a template called application/new. It looks for one here because the PostsController inherits from ApplicationController
  • :formats specifies the format of template to be served in response. The default format is :html, and so Rails is looking for an HTML template.
  • :handlers, is telling us what template handlers could be used to render our template.
  • When you call form_for, you pass it an identifying object for this form. In this case, it's the symbol :post. This tells the form_for helper what this form is for.
  • that the action attribute for the form is pointing at /posts/new
  • When a form is submitted, the fields of the form are sent to Rails as parameters.
  • parameters can then be referenced inside the controller actions, typically to perform a particular task
  • params method is the object which represents the parameters (or fields) coming in from the form.
  • Active Record is smart enough to automatically map column names to model attributes,
  • Rails uses rake commands to run migrations, and it's possible to undo a migration after it's been applied to your database
  • every Rails model can be initialized with its respective attributes, which are automatically mapped to the respective database columns.
  • migration creates a method named change which will be called when you run this migration.
  • The action defined in this method is also reversible, which means Rails knows how to reverse the change made by this migration, in case you want to reverse it later
  • Migration filenames include a timestamp to ensure that they're processed in the order that they were created.
  • @post.save returns a boolean indicating whether the model was saved or not.
  • prevents an attacker from setting the model's attributes by manipulating the hash passed to the model.
  • If you want to link to an action in the same controller, you don't need to specify the :controller option, as Rails will use the current controller by default.
  • inherits from ActiveRecord::Base
  • Active Record supplies a great deal of functionality to your Rails models for free, including basic database CRUD (Create, Read, Update, Destroy) operations, data validation, as well as sophisticated search support and the ability to relate multiple models to one another.
  • Rails includes methods to help you validate the data that you send to models
  • Rails can validate a variety of conditions in a model, including the presence or uniqueness of columns, their format, and the existence of associated objects.
  • redirect_to will tell the browser to issue another request.
  • rendering is done within the same request as the form submission
  • Each request for a comment has to keep track of the post to which the comment is attached, thus the initial call to the find method of the Post model to get the post in question.
  • pluralize is a rails helper that takes a number and a string as its arguments. If the number is greater than one, the string will be automatically pluralized.
  • The render method is used so that the @post object is passed back to the new template when it is rendered.
  • The method: :patch option tells Rails that we want this form to be submitted via the PATCH HTTP method which is the HTTP method you're expected to use to update resources according to the REST protocol.
  • it accepts a hash containing the attributes that you want to update.
  • field_with_errors. You can define a css rule to make them standout
  • belongs_to :post, which sets up an Active Record association
  • creates comments as a nested resource within posts
  • call destroy on Active Record objects when you want to delete them from the database.
  • Rails allows you to use the dependent option of an association to achieve this.
  • store all external data as UTF-8
  • you're better off ensuring that all external data is UTF-8
  • use UTF-8 as the internal storage of your database
  • Rails defaults to converting data from your database into UTF-8 at the boundary.
  • :patch
  • By default forms built with the form_for helper are sent via POST
  • The :method and :'data-confirm' options are used as HTML5 attributes so that when the link is clicked, Rails will first show a confirm dialog to the user, and then submit the link with method delete. This is done via the JavaScript file jquery_ujs which is automatically included into your application's layout (app/views/layouts/application.html.erb) when you generated the application.
  • Without this file, the confirmation dialog box wouldn't appear.
  • just defines the partial template we want to render
  • As the render method iterates over the @post.comments collection, it assigns each comment to
  • a local variable named the same as the partial
  • use the authentication system
  • require and permit
  • the method is often made private to make sure it can't be called outside its intended context.
  • standard CRUD actions in each controller in the following order: index, show, new, edit, create, update and destroy.
  • must be placed before any private or protected method in the controller in order to work
張 旭

Active Record Basics - Ruby on Rails Guides - 0 views

  • the model - which is the layer of the system responsible for representing business data and logic.
  • Active Record facilitates the creation and use of business objects whose data requires persistent storage to a database
  • Rails will pluralize your class names to find the respective database table.
  • ...33 more annotations...
  • objects carry both persistent data and behavior which operates on that data
  • Object-Relational Mapping, commonly referred to as its abbreviation ORM, is a technique that connects the rich objects of an application to tables in a relational database management system
  • Represent associations between these models
  • Validate models before they get persisted to the database
  • The idea is that if you configure your applications in the very same way most of the times then this should be the default way.
  • Database Table - Plural with underscores separating words
  • use the ActiveRecord::Base.table_name= method to specify the table name
  • Model Class - Singular with the first letter of each word capitalized
  • Foreign keys - These fields should be named following the pattern singularized_table_name_id
  • Primary keys - By default, Active Record will use an integer column named id as the table's primary key
  • created_at
  • updated_at
  • (table_name)_count - Used to cache the number of belonging objects on associations.
  • Single Table Inheritance (STI)
  • Object Relational Mapping
  • class_name.yml
  • ActiveRecord::Base.primary_key=
  • CRUD is an acronym for the four verbs we use to operate on data: Create, Read, Update and Delete.
  • new method will return a new object
  • create will return the object and save it to the database.
  • Using the new method, an object can be instantiated without being saved
  • user.save will commit the record to the database
  • update_all class method
  • an Active Record object can be destroyed which removes it from the database
  • Validation is a very important issue to consider when persisting to database, so the methods create, save and update take it into account when running: they return false when validation fails and they didn't actually perform any operation on database.
  • a bang counterpart
  • Active Record callbacks allow you to attach code to certain events in the life-cycle of your models
  • Rails keeps track of which files have been committed to the database and provides rollback features
  • rake db:migrate
  • rake db:rollback
  • Convention over Configuration
    • 張 旭
       
      Model 是單數,Table 是複數。想象一下,處理 Object 的時候是逐一處理,但是存放的地方是放了一堆 Objects。
    • 張 旭
       
      外鍵是單數的形式,這也很好理解:因為關聯到的是一個外部的 Object
張 旭

elabs/pundit: Minimal authorization through OO design and pure Ruby classes - 0 views

  • The class implements some kind of query method
  • Pundit will call the current_user method to retrieve what to send into this argumen
  • put these classes in app/policies
  • ...49 more annotations...
  • in leveraging regular Ruby classes and object oriented design patterns to build a simple, robust and scaleable authorization system
  • map to the name of a particular controller action
  • In the generated ApplicationPolicy, the model object is called record.
  • record
  • authorize
  • authorize would have done something like this: raise "not authorized" unless PostPolicy.new(current_user, @post).update?
  • pass a second argument to authorize if the name of the permission you want to check doesn't match the action name.
  • you can chain it
  • authorize returns the object passed to it
  • the policy method in both the view and controller.
  • have some kind of view listing records which a particular user has access to
  • ActiveRecord::Relation
  • Instances of this class respond to the method resolve, which should return some kind of result which can be iterated over.
  • scope.where(published: true)
    • 張 旭
       
      我想大概的意思就是:如果是 admin 可以看到全部 post,如果不是只能看到 published = true 的 post
  • use this class from your controller via the policy_scope method:
  • PostPolicy::Scope.new(current_user, Post).resolve
  • policy_scope(@user.posts).each
  • This method will raise an exception if authorize has not yet been called.
  • verify_policy_scoped to your controller. This will raise an exception in the vein of verify_authorized. However, it tracks if policy_scope is used instead of authorize
  • need to conditionally bypass verification, you can use skip_authorization
  • skip_policy_scope
  • Having a mechanism that ensures authorization happens allows developers to thoroughly test authorization scenarios as units on the policy objects themselves.
  • Pundit doesn't do anything you couldn't have easily done yourself. It's a very small library, it just provides a few neat helpers.
  • all of the policy and scope classes are just plain Ruby classes
  • rails g pundit:policy post
  • define a filter that redirects unauthenticated users to the login page
  • fail more gracefully
  • raise Pundit::NotAuthorizedError, "must be logged in" unless user
  • having rails handle them as a 403 error and serving a 403 error page.
  • config.action_dispatch.rescue_responses["Pundit::NotAuthorizedError"] = :forbidden
  • with I18n to generate error messages
  • retrieve a policy for a record outside the controller or view
  • define a method in your controller called pundit_user
  • Pundit strongly encourages you to model your application in such a way that the only context you need for authorization is a user object and a domain model that you want to check authorization for.
  • Pundit does not allow you to pass additional arguments to policies
  • authorization is dependent on IP address in addition to the authenticated user
  • create a special class which wraps up both user and IP and passes it to the policy.
  • set up a permitted_attributes method in your policy
  • policy(@post).permitted_attributes
  • permitted_attributes(@post)
  • Pundit provides a convenient helper method
  • permit different attributes based on the current action,
  • If you have defined an action-specific method on your policy for the current action, the permitted_attributes helper will call it instead of calling permitted_attributes on your controller
  • If you don't have an instance for the first argument to authorize, then you can pass the class
  • restart the Rails server
  • Given there is a policy without a corresponding model / ruby class, you can retrieve it by passing a symbol
  • after_action :verify_authorized
  • It is not some kind of failsafe mechanism or authorization mechanism.
  • Pundit will work just fine without using verify_authorized and verify_policy_scoped
  •  
    "Minimal authorization through OO design and pure Ruby classes"
張 旭

Introduction to GitLab Flow | GitLab - 0 views

  • Git allows a wide variety of branching strategies and workflows.
  • not integrated with issue tracking systems
  • The biggest problem is that many long-running branches emerge that all contain part of the changes.
  • ...47 more annotations...
  • most organizations practice continuous delivery, which means that your default branch can be deployed.
  • Merging everything into the master branch and frequently deploying means you minimize the amount of unreleased code, which is in line with lean and continuous delivery best practices.
  • you can deploy to production every time you merge a feature branch.
  • deploy a new version by merging master into the production branch.
  • you can have your deployment script create a tag on each deployment.
  • to have an environment that is automatically updated to the master branch
  • commits only flow downstream, ensures that everything is tested in all environments.
  • first merge these bug fixes into master, and then cherry-pick them into the release branch.
  • Merging into master and then cherry-picking into release is called an “upstream first” policy
  • “merge request” since the final action is to merge the feature branch.
  • “pull request” since the first manual action is to pull the feature branch
  • it is common to protect the long-lived branches
  • After you merge a feature branch, you should remove it from the source control software
  • When you are ready to code, create a branch for the issue from the master branch. This branch is the place for any work related to this change.
  • A merge request is an online place to discuss the change and review the code.
  • If you open the merge request but do not assign it to anyone, it is a “Work In Progress” merge request.
  • Start the title of the merge request with “[WIP]” or “WIP:” to prevent it from being merged before it’s ready.
  • To automatically close linked issues, mention them with the words “fixes” or “closes,” for example, “fixes #14” or “closes #67.” GitLab closes these issues when the code is merged into the default branch.
  • If you have an issue that spans across multiple repositories, create an issue for each repository and link all issues to a parent issue.
  • With Git, you can use an interactive rebase (rebase -i) to squash multiple commits into one or reorder them.
  • you should never rebase commits you have pushed to a remote server.
  • Rebasing creates new commits for all your changes, which can cause confusion because the same change would have multiple identifiers.
  • if someone has already reviewed your code, rebasing makes it hard to tell what changed since the last review.
  • never rebase commits authored by other people.
  • it is a bad idea to rebase commits that you have already pushed.
  • always use the “no fast-forward” (--no-ff) strategy when you merge manually.
  • you should try to avoid merge commits in feature branches
  • people avoid merge commits by just using rebase to reorder their commits after the commits on the master branch. Using rebase prevents a merge commit when merging master into your feature branch, and it creates a neat linear history.
  • you should never rebase commits you have pushed to a remote server
  • Sometimes you can reuse recorded resolutions (rerere), but merging is better since you only have to resolve conflicts once.
  • not frequently merge master into the feature branch.
  • utilizing new code,
  • resolving merge conflicts
  • updating long-running branches.
  • just cherry-picking a commit.
  • If your feature branch has a merge conflict, creating a merge commit is a standard way of solving this.
  • keep your feature branches short-lived.
  • split your features into smaller units of work
  • you should try to prevent merge commits, but not eliminate them.
  • Your codebase should be clean, but your history should represent what actually happened.
  • Splitting up work into individual commits provides context for developers looking at your code later.
  • push your feature branch frequently, even when it is not yet ready for review.
  • Commit often and push frequently
  • A commit message should reflect your intention, not just the contents of the commit.
  • Testing before merging
  • When using GitLab flow, developers create their branches from this master branch, so it is essential that it never breaks. Therefore, each merge request must be tested before it is accepted.
  • When creating a feature branch, always branch from an up-to-date master
  •  
    "Git allows a wide variety of branching strategies and workflows."
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