StackStorm介紹
StackStorm是一個強大的自動化平臺，結合DevOps和ChatOps，提供可擴展、靈活和健壯的工具鏈用於應用、服務和工作流的自動化能力。
Action
Action是StackStrom事件觸發後的處理方式，也就是自動化任務的執行體。
內置Action
StackStorm內置了許多Action，可以通過命令行查詢:
# List all available actions (note that output may be lengthy)$ st2 action list # List all actions in "linux" pack$ st2 action list -p linux |
比較常用的Action,比如core.local就是在本地執行Linux命令，我們可以查詢Action的詳細說明：
$ st2 action get core.local+-------------+--------------------------------------------------------------+| Property | Value |+-------------+--------------------------------------------------------------+| id | 5afa49082b2556016fc96b82 || uid | action:core:local || ref | core.local || pack | core || name | local || description | Action that executes an arbitrary Linux command on the || | localhost. || enabled | True || entry_point | || runner_type | local-shell-cmd || parameters | { || | "cmd": { || | "required": true, || | "type": "string", || | "description": "Arbitrary Linux command to be || | executed on the local host." || | }, || | "sudo": { || | "immutable": true || | } || | } || notify | || tags | |+-------------+--------------------------------------------------------------+ |
- pack: Action歸屬的Pack，StackStorm中Action和Workflow，Rule和Sensor都歸屬於Pack。可以通過st2 packlist查詢Pack。
entry_point：Action的執行入口，類似Docker的ENTRYPOINT。- runner_type：Action的Action Runner類型，core.local的Runner是local-shell-cmd
- parameters : Action的參數信息，core.local的參數有cmd和sudo，其中cmd是必須的，即需要運行的命令
熟悉Action的詳情後，就可以執行Action：
$ st2 run core.local cmd="echo test"id: 5afa92a22b2556015687cccdstatus: succeededparameters: cmd: echo testresult: failed: false return_code: 0 stderr: '' stdout: test succeeded: true |
除了使用st2 run執行Action，也可以使用st2action execute執行，不同的是execute是屬於異步的方式：
$ st2 action execute core.http url="http://httpbin.org/get"To get the results, execute: st2 execution get 5afa93352b2556015687ccd3 To view output in real-time, execute: st2 execution tail 5afa93352b2556015687ccd3 $ st2 execution get 5afa93352b2556015687ccd3id: 5afa93352b2556015687ccd3status: succeeded (1s elapsed)parameters: url: http://httpbin.org/getresult: body: args: {} headers: Accept: '*/*' Accept-Encoding: gzip, deflate Connection: close Host: httpbin.org User-Agent: st2/v2.7.1 X-Stanley-Action: http origin: 36.251.248.174 url: http://httpbin.org/get headers: Access-Control-Allow-Credentials: 'true' Access-Control-Allow-Origin: '*' Connection: keep-alive Content-Length: '224' Content-Type: application/json Date: Tue, 15 May 2018 07:58:45 GMT Server: gunicorn/19.8.1 Via: 1.1 vegur parsed: true status_code: 200 |
自定義Action
StackStorm除了內置Action，有可以定製Action，一個Action的元數據包括：
name- Name of the action.runner_type- The type of runner to execute the action.enabled- Action cannot be invoked when disabled.entry_point- Location of the action launch script relative to the/opt/stackstorm/packs/${pack_name}/actions/directory.parameters- A dictionary of parameters and optional metadata describing type and default. The metadata is structured data following the JSON Schema specification draft 4. The common parameter types allowed arestring,boolean,number(whole numbers and decimal numbers - e.g.1.0,1,3.3333, etc.),object,integer(whole numbers only -1,1000, etc.) andarray. If metadata is provided, input args are validated on action execution. Otherwise, validation is skipped.
StackStorm提供了對Shell的支持，可以非常方便地將已有的腳本接入StackStorm。現在有一個Shell腳本script.sh#!/usr/bin/env bash MESSAGE=$1echo ${MESSAGE} |
然後創建Action的元數據文件my-action.yaml：
---name: "my-action" runner_type: "local-shell-script" description: "Echo a message" enabled: true entry_point: "script.sh" parameters: message: type: "string" description: "Message to write" required: true position: 0 |
創建Action：
$ st2 action create my-action.yaml +-------------+-------------------------------------------+ | Property | Value | +-------------+-------------------------------------------+ | id | 5afbe8f02b2556015687ce43 | | name | my-action | | pack | default | | description | Echo a message | | enabled | True | | entry_point | script.sh | | notify | | | parameters | { | | | "message": { | | | "position": 0, | | | "required": true, | | | "type": "string", | | | "description": "Message to write" | | | } | | | } | | ref | default.my-action | | runner_type | local-shell-script | | tags | | | uid | action:default:my-action | +-------------+-------------------------------------------+ |
默認的Pack是default，需要將shell腳本拷貝到/opt/stackstorm/packs/default/actions/script.sh。
然後執行這個Action:
$ st2 run default.my-action message="Hello1" . id: 5afbe9bc2b2556015687ce4e status: succeeded parameters: message: Hello1 result: failed: false return_code: 0 stderr: '' stdout: Hello1 succeeded: true |
ActionRunner
ActionRunner是Action的執行環境， Action Runner實際上就是一系列的工作進程，ActionRunner根據StackStorm調度來進行執行Action，可以通過命令查詢到進程：
$ st2ctl status##### st2 components status #####st2actionrunner PID: 93st2actionrunner PID: 97st2actionrunner PID: 100st2actionrunner PID: 103st2actionrunner PID: 109st2actionrunner PID: 116st2actionrunner PID: 122st2actionrunner PID: 127st2actionrunner PID: 130st2actionrunner PID: 138st2actionrunner PID: 143st2actionrunner PID: 147 |
StackStorm支持不同類型的執行方式，比如Shell腳本，Python腳本或者HTTP調用等等，不難理解這些是以插件的形式存在的，StackStorm內置了基本的一些Action Runner，如下表所示。除了StackStorm的內置類型ActionRunner，當然用戶也可以自定義ActionRunner。
Action Runner | Description |
local-shell-cmd | This is the local runner. This runner executes a Linux command on the same host where StackStorm components are running. |
local-shell-script | This is the local runner. Actions are implemented as scripts. They are executed on the same hosts where StackStorm components are running. |
remote-shell-cmd | This is a remote runner. This runner executes a Linux command on one or more remote hosts provided by the user. |
remote-shell-script | This is a remote runner. Actions are implemented as scripts. They run on one or more remote hosts provided by the user. |
python-script | This is a Python runner. Actions are implemented as Python classes with arun method. They run locally on the same machine where StackStorm components are running. |
http-request | HTTP client which performs HTTP requests for running HTTP actions. |
action-chain | This runner supports executing simple linear work-flows. |
mistral-v2 | Those runners are built on top of the Mistral OpenStack project and support executing complex work-flows. |
cloudslang | This runner is built on top of the CloudSlang project and supports executing complex workflows. |
inquirer | This runner provides the core logic of the :doc:`Inquiries </inquiries>` feature. |
ActionChain
Workflow是Action集合，Workflow能夠定義Action的執行順序和條件，組合一系列Action完成複雜的任務。StackStorm支持2種類型的Workflow，其中ActionChain是StackStorm定義的Action鏈。
創建ActionChain需要提供元數據文件echochain.meta.yaml：
--- # Action definition metadata name: "echochain" description: "Simple Action Chain workflow"
# `runner_type` has value `action-chain` to identify that action is an ActionChain. runner_type: "action-chain"
# `entry_point` path to the ActionChain definition file, relative to the pack's action directory. entry_point: "chains/echochain.yaml"
enabled: true parameters: skip_notify: default: - c2 notify: on-complete: message: "\"@channel: Action succeeded.\"" routes: - "slack" |
ActionChain本質也是一種Action，這個ActionChain元數據文件上也是就Action的規格文件，其中runner_type指定爲action-chain，entry_point指定的是ActionChain的規則文件echochain.yaml：
--- chain: - name: "c1" ref: "core.local" parameters: cmd: "echo c1" on-success: "c2" on-failure: "c4" - name: "c2" ref: "core.local" parameters: cmd: "echo \"c2: parent exec is {{action_context.parent.execution_id}}.\"" on-success: "c3" on-failure: "c4" - name: "c3" ref: "core.local" parameters: cmd: "echo c3&&exit 1" on-failure: "c4" - name: "c4" ref: "core.local" parameters: cmd: "echo fail c4" default: "c1" |
ActionChain的規則文件定了4個子任務：c1,c2,c3和c4，包括每個子任務的運行類型和參數，然後還有成功或者失敗後的執行步驟，這樣一來就構成了工作流。
注意：默認創建的Pack是default, 對應的Pack目錄在/opt/stackstorm/packs/default，需要把echochain.yaml拷貝到
/opt/stackstorm/packs/default/actions/chains/echochain.yaml
創建ActionChain:
$ st2 action create echochain.meta.yaml |
執行ActionChain:
$ st2 run default.echochain...id: 5afaab9c2b2556015687cd7baction.ref: default.echochainparameters: Nonestatus: succeededresult_task: c4result: failed: false return_code: 0 stderr: '' stdout: fail c4 succeeded: truestart_timestamp: Tue, 15 May 2018 09:42:52 UTCend_timestamp: Tue, 15 May 2018 09:42:57 UTC+--------------------------+------------------------+------+------------+-------------------------------+| id | status | task | action | start_timestamp |+--------------------------+------------------------+------+------------+-------------------------------+| 5afaab9c2b2556007f0afa2b | succeeded (1s elapsed) | c1 | core.local | Tue, 15 May 2018 09:42:52 UTC || 5afaab9d2b2556007f0afa2d | succeeded (1s elapsed) | c2 | core.local | Tue, 15 May 2018 09:42:53 UTC || 5afaab9f2b2556007f0afa2f | failed (0s elapsed) | c3 | core.local | Tue, 15 May 2018 09:42:55 UTC || 5afaaba02b2556007f0afa31 | succeeded (0s elapsed) | c4 | core.local | Tue, 15 May 2018 09:42:56 UTC |+--------------------------+------------------------+------+------------+-------------------------------+ |
可以查詢子任務的運行情況:
$ st2 execution get 5afb88102b25560074358c7c id: 5afb88102b25560074358c7cstatus: succeeded (0s elapsed)parameters: cmd: 'echo "c2: parent exec is 5afb880e2b2556015687cd7e."'result: failed: false return_code: 0 stderr: '' stdout: 'c2: parent exec is 5afb880e2b2556015687cd7e.' succeeded: true |
可以重跑失敗的子任務：
$ st2 execution re-run 5afb88112b25560074358c7e.id: 5afb8cf02b2556015687cd82status: failedparameters: cmd: echo c3&&exit 1result: failed: true return_code: 1 stderr: '' stdout: c3 succeeded: false |
參考
- https://github.com/StackStorm/st2docs/blob/master/docs/source/actions.rst
- https://github.com/StackStorm/st2docs/blob/master/docs/source/actionchain.rst
作者簡介
吳龍輝，現任網宿科技雲計算架構師，致力於雲計算PaaS的研究和實踐，《Kubernetes實戰》作者，活躍於CloudFoundry，Docker，Kubernetes等開源社區，貢獻代碼和撰寫技術文檔。郵箱：[email protected]