postgres

README

Postgres writer

Postgres writer provides message repository implementation for Postgres.

Configuration

The service is configured using the environment variables presented in the following table. Note that any unset variables will be replaced with their default values.

Variable	Description	Default
MF_NATS_URL	NATS instance URL	nats://localhost:4222
MF_POSTGRES_WRITER_LOG_LEVEL	Service log level	error
MF_POSTGRES_WRITER_PORT	Service HTTP port	9104
MF_POSTGRES_WRITER_DB_HOST	Postgres DB host	postgres
MF_POSTGRES_WRITER_DB_PORT	Postgres DB port	5432
MF_POSTGRES_WRITER_DB_USER	Postgres user	mainflux
MF_POSTGRES_WRITER_DB_PASS	Postgres password	mainflux
MF_POSTGRES_WRITER_DB	Postgres database name	messages
MF_POSTGRES_WRITER_DB_SSL_MODE	Postgres SSL mode	disabled
MF_POSTGRES_WRITER_DB_SSL_CERT	Postgres SSL certificate path	""
MF_POSTGRES_WRITER_DB_SSL_KEY	Postgres SSL key	""
MF_POSTGRES_WRITER_DB_SSL_ROOT_CERT	Postgres SSL root certificate path	""
MF_POSTGRES_WRITER_SUBJECTS_CONFIG	Configuration file path with subjects list	/config/subjects.toml
MF_POSTGRES_WRITER_CONTENT_TYPE	Message payload Content Type	application/senml+json

Deployment

  version: "3.7"
  postgres-writer:
    image: mainflux/postgres-writer:[version]
    container_name: [instance name]
    depends_on:
      - postgres
      - nats
    restart: on-failure
    environment:
      MF_NATS_URL: [NATS instance URL]
      MF_POSTGRES_WRITER_LOG_LEVEL: [Service log level]
      MF_POSTGRES_WRITER_PORT: [Service HTTP port]
      MF_POSTGRES_WRITER_DB_HOST: [Postgres host]
      MF_POSTGRES_WRITER_DB_PORT: [Postgres port]
      MF_POSTGRES_WRITER_DB_USER: [Postgres user]
      MF_POSTGRES_WRITER_DB_PASS: [Postgres password]
      MF_POSTGRES_WRITER_DB: [Postgres database name]
      MF_POSTGRES_WRITER_DB_SSL_MODE: [Postgres SSL mode]
      MF_POSTGRES_WRITER_DB_SSL_CERT: [Postgres SSL cert]
      MF_POSTGRES_WRITER_DB_SSL_KEY: [Postgres SSL key]
      MF_POSTGRES_WRITER_DB_SSL_ROOT_CERT: [Postgres SSL Root cert]
      MF_POSTGRES_WRITER_SUBJECTS_CONFIG: [Configuration file path with subjects list]
      MF_POSTGRES_WRITER_CONTENT_TYPE: [Message payload Content Type]
    ports:
      - 9104:9104
    networks:
      - docker_mainflux-base-net
    volume:
      - ./subjects.yaml:/config/subjects.yaml

To start the service, execute the following shell script:

# download the latest version of the service
git clone https://gitee.com/shtemmi/iotflux

cd mainflux

# compile the postgres writer
make postgres-writer

# copy binary to bin
make install

# Set the environment variables and run the service
MF_NATS_URL=[NATS instance URL] \
MF_POSTGRES_WRITER_LOG_LEVEL=[Service log level] \
MF_POSTGRES_WRITER_PORT=[Service HTTP port] \
MF_POSTGRES_WRITER_DB_HOST=[Postgres host] \
MF_POSTGRES_WRITER_DB_PORT=[Postgres port] \
MF_POSTGRES_WRITER_DB_USER=[Postgres user] \
MF_POSTGRES_WRITER_DB_PASS=[Postgres password] \
MF_POSTGRES_WRITER_DB=[Postgres database name] \
MF_POSTGRES_WRITER_DB_SSL_MODE=[Postgres SSL mode] \
MF_POSTGRES_WRITER_DB_SSL_CERT=[Postgres SSL cert] \
MF_POSTGRES_WRITER_DB_SSL_KEY=[Postgres SSL key] \
MF_POSTGRES_WRITER_DB_SSL_ROOT_CERT=[Postgres SSL Root cert] \
MF_POSTGRES_WRITER_SUBJECTS_CONFIG=[Configuration file path with subjects list] \
$GOBIN/mainflux-postgres-writer

Usage

Starting service will start consuming normalized messages in SenML format.

Documentation

Overview

Package postgres contains repository implementations using Postgres as the underlying database.

Index

• Variables
• func Connect(cfg Config) (*sqlx.DB, error)
• func New(db *sqlx.DB) writers.MessageRepository
• type Config

Variables

var (
	// ErrInvalidMessage indicates that service received message that
	// doesn't fit required format.
	ErrInvalidMessage = errors.New("invalid message representation")
)

Functions

func Connect

func Connect(cfg Config) (*sqlx.DB, error)

Connect creates a connection to the PostgreSQL instance and applies any unapplied database migrations. A non-nil error is returned to indicate failure.

func New

func New(db *sqlx.DB) writers.MessageRepository

New returns new PostgreSQL writer.

Types

type Config

type Config struct {
	Host        string
	Port        string
	User        string
	Pass        string
	Name        string
	SSLMode     string
	SSLCert     string
	SSLKey      string
	SSLRootCert string
}

Config defines the options that are used when connecting to a PostgreSQL instance