simplepostgresclient

{ "image": "direktiv/simplepostgresclient", "desc": "Perform simple interactions on a PostgreSQL database. " }

Simple Postgres Client

Perform simple interactions on a PostgreSQL database.

Direktiv

Here's an example of how this could be used in Direktiv to store event data in a database.

id: eventOnboarder
start:
  type: event
  event: 
    type: com.github.pull.create
    filters:
      source: "https://github.com/cloudevents/spec/pull"
functions:
- id: postgres
  image: direktiv/simple-postgres-client:v1
states:
- id: store
  type: action
  action:
    function: postgres
    secrets: ["DB_PASSWORD"]
    input:
      conn: "postgres://direktiv:jq(.secrets.DB_PASSWORD)@203.0.113.5:5432/github_events_db"
      table: "github_events"
      transaction: 
        - type: "insert"
          data: jq(."com.github.pull.create")

Input

The Simple Postgres Client can support a handful of different operations, and can chain them together into simple transactions. Here's an example input, which will be explained in further detail below.

input:
  conn: "postgres://direktiv:password@localhost:5432/postgres?sslmode=disable"
  table: "test"
  transaction: 
    - type: "update"
      where:
        name: null
      set:
        name: "jon"
        age: 24

Top-Level Parameters

The following fields can appear on the first level of the input JSON:

The conn field must be a string that can be used to connect to a Postgres database.

The table field must identify a table within the database. All functions supported by the Simple Postgres Client work on the same table.

The debug field may be either true or false, or omitted entirely. If set to true, the queries logged will not obscure values.

The real input goes into the transaction array. Each element in the transaction array must be an object that conforms to one of the four operation inputs outlined below (delete, insert, select, or update). All "steps" in this transaction array will be performed within a single database transaction, meaning they'll all be committed or rolled back together.

Delete Input

An delete step is identified by the required "type": "delete" parameter. It also requires a where parameter, which must be an object that contains only key-value pairs of primitive types.

input:
  type: "delete"
  where: 
    a: 1

Insert Input

An insert step is identified by the required "type": "insert" parameter. It also requires data, which can be either a single object or an array of objects. All data objects must contain only key-value pairs of primitive types.

input:
  type: "insert"
  data: 
    - b: "B"
      c: 2
      d: null

Each data object will be inserted into the database with the keys used to identify columns.

Select Input

A select step is identified by the required "type": "select" parameter. It also requires where and fields parameters. The where parameter must be an object that contains only key-value pairs of primitive types. The fields parameter can be either "fields": "*" or an array of strings that select specific columns to appear in the output of the step.

input:
  type: "select"
  where: 
    a: 1
  fields: "*"

Update Input

An update step is identified by the required "type": "update" parameter. It also requires where and set parameters, which are both objects that must contain only key-value pairs of primitive types.

input:
  type: "update"
  where: 
    a: 1
  set:
    b: "B"
    c: 2
    d: null

Output

Output data will be stored as a JSON array with each element representing the results of one step in the transaction.

Example

[{ "rowsAffected": 3 }, { "rows": [{"id": 1}, {"id": 2}] }]

Delete Output

The output from a delete step will only contain the number of rowsAffected by the delete operation.

Insert Output

The output from an insert step will be an empty object {}.

Select Output

The output from a select step will be an object containing an array of rows, each of which is itself an object with keys and values extracted from the database.

Update Output

The output from an update step will only contain the number of rowsAffected by the update operation.

Error

If an error occurs, the transaction will be rolled-back and the error will be logged. It will also be found in /direktiv-data/error.json and have the following structure:

{
  "errorCode": "error.conn",
  "errorMsg": "Failed to connect to database."
}