Denoflow

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Table of Contents

About

Denoflow is a serverless, automated workflow based yaml workflow file, you can use any Deno module or Typescript/Javascript code to run your workflow.

It’s still a very earlier phase, use with care!

The Ideal result is having some app schemas, using rjsf to render a web gui, gui can help us to generate yaml configs.

But now we can only write yaml by ourself, and actually, it’s not that hard.

Getting Started

Fetch from Hacker News API to webhook example:

mkdir workflows
touch workflows/fetch.yml
sources:
  - use: fetch
    args:
      - https://test.owenyoung.com/slim.json
    run: return ctx.result.json()
    itemsPath: hits
    key: objectID
    format: return ctx.item.title
    limit: 1
steps: 
  - use: fetch
    args:
      - https://enyvb91j5zjv9.x.pipedream.net/
      - method: POST
        headers:
          'Content-Type': 'application/json'
        body: ${{JSON.stringify(ctx.item)}}

Open: https://requestbin.com/r/enyvb91j5zjv9/23eNPamD4DK4YK1rfEB1FAQOKIj , See live webhook request.

deno run --allow-read --allow-net --allow-write --allow-env --allow-run --unstable https://denopkg.com/denoflow/denoflow@main/cli.ts run

It will scan the workflows directory and run all valid .yml files.

RSS Feed to Discord Webhook Message

touch workflows/rss.yml
sources:
  - use: fetch
    args:
      - https://actionsflow.github.io/test-page/hn-rss.xml
    run: |
      const rss = await import("https://deno.land/x/rss/mod.ts");
      const xml = await ctx.result.text();
      const feed = await rss.parseFeed(xml);
      return feed.entries;
steps:
  - use: fetch
    args:
      - ${{ctx.env.DISCORD_WEBHOOK}}
      - method: POST
        headers:
          'Content-Type': 'application/json'
        body: ${{ JSON.stringify({content:ctx.item.title.value}) }}
deno run --allow-read --allow-net --allow-write --allow-run --allow-env --unstable https://denopkg.com/denoflow/denoflow@main/cli.ts run

Life Cycle

  1. on?: when to run the workflow, Record<EventType,EventConfig>, can be schedule or http,always, default is always.

  2. sources?: where to fetch the data, Source[], can be one or more sources. Every source should return an array of items.

    1. from?: import ts/js script from url or file path
    2. use?: run moduleName from above from , or if from is not provided, run globalFunction like fetch, args will be passed to the function, the return value will be attached to ctx.result and ctx.sources[index].result
    3. run?: run ts/js code, you can handle use result here. Return a result that can be stringified to json. The return value will be attached to ctx.result and ctx.sources[index].result
    4. itemsPath?: the path to the items in the result, like hits in https://test.owenyoung.com/slim.json
    5. key?: the key to identify the item, like objectID in https://test.owenyoung.com/slim.json, if not provided, will use id, denoflow will hash the id, then the same item with id will be skipped.
    6. limit, number limit the number of items of this source.
    7. format, string, every item will be call format function
    8. cmd?: string, exec a shell command after all other task, the return value will be attached to ctx.cmdResult and ctx.sources[index].cmdResult

  3. filter? filter from all sources items, expected return a new items array. The result will be attached to the ctx.items

    1. from?: import ts/js script from url or file path
    2. use?: run moduleName from above from , or if from is not provided, run globalFunction like fetch, args will be passed to the function, the return value will be attached to ctx.result and filter.result
    3. run?: run ts/js code, you can handle use result here. Return a items that be filted. The return value will be attached to ctx.result, ctx.filter.result, ctx.items, e.g. run: return ctx.items.filter(item => item.title.value.includes('test'))
    4. limit?, limit the number of items
    5. cmd?: string, exec a shell command after all other task, the return value will be attached to ctx.cmdResult and filter.cmdResult

  4. steps? the steps to run, Step[], can be one or more steps.

    1. from?: import script from url or file path
    2. use?: run moduleName from above from , or if from is not provided, run globalFunction like fetch, args will be passed to the function
    3. run?: run ts/js code, you can handle use result here. Return a result that can be stringified to json. the result will be attached to the ctx.steps[index].result
    4. cmd?: exec shell commands, will be run after run, the result will be attached to the ctx.steps[index].cmdResult

Prerequisites

Install Deno first.

Installing

deno install -n denoflow --allow-read --allow-net --allow-write --allow-run --allow-env  https://denopkg.com/denoflow/denoflow@main/cli.ts

Then, you can run it with denoflow run , or denoflow run <files>

Usage 

denoflow/0.0.0

Usage:
  $ denoflow run [...files]

Options:
  --force     Force run workflow files, if true, will ignore to read/save state (default: false)
  --limit     max items for workflow every runs 
  -h, --help  Display this message

YAML Syntax

You can use ${{variable}} in any fields to inject variables into your workflow, we inject ctx variable in template and script. For example:

Expressions

steps:
  - if: ${{ctx.items.lengh>10}}
    run: console.log(ctx.item);

All ctx see [Context] in the following doc.

State

You can simply use ctx.state to get or set state, for example:

let currentState = ctx.state || {};

let sent = ctx.state.sent || [];

if(sent.includes(ctx.item.id)){
  sent.push(ctx.item.id);
}

ctx.state = {
  sent
};

// deno flow will save the state for you , next you can read it.
return;

The state will be saved to data folder in json format. You can also use sqlite to store the state. Just set general.database: sqlite://data.sqlite in your workflow config file.

Syntax

All workflow syntax:

// WorkflowOptions File Structure
export interface WorkflowOptions {
  general?: GeneralOptions;
  env?: Record<string, string | undefined>;
  on?: Record<EventType, EventOptions>;
  sources?: SourceOptions[];
  filter?: FilterOptions;
  steps?: StepOptions[];
}
// general: General Options
export interface GeneralOptions {
  sleep?: string | number;
  debug?: boolean;
  if? : string | boolean;
  database?: string; // default is json://data ,   can be sqlite://data.sqlite
}

// on:  Event Options
type EventOptions = ScheduleOptions | HttpOptions;
enum EventType {
  Schedule = "schedule",
  Http = "http",
  Always = "always", // default
}

// sources: Source Options
export interface SourceOptions extends FilterOptions {
  itemsPath?: string;
  limit?: number;
  key?: string;
  force?: boolean;
  format?: string;
}

// filter: FilterOptions Options
export interface FilterOptions extends StepOptions {
  limit?: number;
}

// step: StepOptionss Options
export interface StepOptions extends GeneralOptions {
  id?: string;
  from?: string;
  use?: string;
  args?: unknown[];
  run?: string;
  if?: string | boolean;
  env?: Record<string, string | undefined>;
  // run shell command
  cmd?: string;
  continueOnError?: boolean;
}

export interface StepResponse {
  result: unknown;
  ok: boolean;
  isRealOk: boolean;
  error?: unknown;
  cmdResult?: string;
  cmdCode?: number;
  cmdOk?: boolean;
  cmdError?: string;
}
// ctx: all ctx you may need
export interface PublicContext {
  env: Record<string, string | undefined>; // env vars
  cwd: string; // current working directory
  workflowPath: string; // workflowfile absolute path
  workflowRelativePath: string; // workflow file path relative to cwd
  workflowCwd: string; // workflow cwd, absolute path
  options?: GeneralOptions; // workflow general options, formated by getDefaultWorkflowOptionsOptions
  result?: unknown; // last step result
  error?: unknown; // last step error
  ok?: boolean; // last step state, true if no error
  isRealOk?: boolean; // last step real state, true if no error, when continueOnError is true, and step is error,  it will be false, but ok will be true
  state: unknown; // workflow state , write/read, change this value, can be persisted
  items: unknown[]; // sources/filter result items
  item?: unknown; // current item that being step handled
  itemIndex?: number; //  current item index that being step handled
  itemKey?: string; // current item unique key that being step handled
  sourceIndex?: number; // current source index , used in sources
  filter?: StepResponse; // filter result
  sources: Record<string | number, StepResponse>; // sources result
  steps: Record<string | number, StepResponse>; // steps results
  stepIndex?: number; // current step index
  cmdResult?: string;
  cmdCode?: number;
  cmdOk?: boolean;
  cmdError?: string;
}

// run workflow options
export interface RunWorkflowOptions extends GeneralOptions {
  force?: boolean;
  limit?: number;
  files?: string[];
}

// schedule options
export interface ScheduleOptions {
  every?: string;
}
// http options
export interface HttpOptions {
  resStatusCode?: number;
  resContentType?: string;
  resBody?: string;
}

Todo

    • Support Sleep Option
    • Support GUI generated workflow
    • Support on options, schedule and http
    • Support clean command