Consul and SQLite Integration

Input and output integration overview

The Consul Input Plugin collects health check metrics from a Consul server, allowing users to monitor service statuses effectively.

Telegraf’s SQL output plugin stores metrics in an SQL database by creating tables dynamically for each metric type. When configured for SQLite, it utilizes a file-based DSN and a minimal SQL schema tailored for lightweight, embedded database usage.

Integration details

Consul

The Consul Input Plugin is designed to gather health check statuses from all services registered with Consul, a tool for service discovery and infrastructure management. By querying the Consul API, this plugin helps users monitor the health of their services and ensure that they are operational and meeting service level agreements. It does not provide telemetry data, but users can utilize StatsD if they want to collect those metrics. The plugin offers configuration options to connect to the Consul server, manage authentication, and specify how to handle tags derived from health checks.

SQLite

The SQL output plugin writes Telegraf metrics to an SQL database using a dynamic schema where each metric type corresponds to a table. For SQLite, the plugin uses the modernc.org/sqlite driver and requires a DSN in the format of a file URI (e.g., ‘file:/path/to/telegraf.db?cache=shared’). This configuration leverages standard ANSI SQL for table creation and data insertion, ensuring compatibility with SQLite’s capabilities.

Configuration

Consul

[[inputs.consul]]
  ## Consul server address
  # address = "localhost:8500"

  ## URI scheme for the Consul server, one of "http", "https"
  # scheme = "http"

  ## Metric version controls the mapping from Consul metrics into
  ## Telegraf metrics. Version 2 moved all fields with string values
  ## to tags.
  ##
  ##   example: metric_version = 1; deprecated in 1.16
  ##            metric_version = 2; recommended version
  # metric_version = 1

  ## ACL token used in every request
  # token = ""

  ## HTTP Basic Authentication username and password.
  # username = ""
  # password = ""

  ## Data center to query the health checks from
  # datacenter = ""

  ## Optional TLS Config
  # tls_ca = "/etc/telegraf/ca.pem"
  # tls_cert = "/etc/telegraf/cert.pem"
  # tls_key = "/etc/telegraf/key.pem"
  ## Use TLS but skip chain & host verification
  # insecure_skip_verify = true

  ## Consul checks' tag splitting
  # When tags are formatted like "key:value" with ":" as a delimiter then
  # they will be split and reported as proper key:value in Telegraf
  # tag_delimiter = ":"

SQLite

[[outputs.sql]]
  ## Database driver
  ## Valid options: mssql (Microsoft SQL Server), mysql (MySQL), pgx (Postgres),
  ## sqlite (SQLite3), snowflake (snowflake.com), clickhouse (ClickHouse)
  driver = "sqlite"

  ## Data source name
  ## For SQLite, the DSN is a filename or URL with the scheme "file:".
  ## Example: "file:/path/to/telegraf.db?cache=shared"
  data_source_name = "file:/path/to/telegraf.db?cache=shared"

  ## Timestamp column name
  timestamp_column = "timestamp"

  ## Table creation template
  ## Available template variables:
  ##  {TABLE}        - table name as a quoted identifier
  ##  {TABLELITERAL} - table name as a quoted string literal
  ##  {COLUMNS}      - column definitions (list of quoted identifiers and types)
  table_template = "CREATE TABLE {TABLE} ({COLUMNS})"

  ## Table existence check template
  ## Available template variables:
  ##  {TABLE} - table name as a quoted identifier
  table_exists_template = "SELECT 1 FROM {TABLE} LIMIT 1"

  ## Initialization SQL (optional)
  init_sql = ""

  ## Maximum amount of time a connection may be idle. "0s" means connections are never closed due to idle time.
  connection_max_idle_time = "0s"

  ## Maximum amount of time a connection may be reused. "0s" means connections are never closed due to age.
  connection_max_lifetime = "0s"

  ## Maximum number of connections in the idle connection pool. 0 means unlimited.
  connection_max_idle = 2

  ## Maximum number of open connections to the database. 0 means unlimited.
  connection_max_open = 0

  ## Metric type to SQL type conversion
  ## The values on the left are the data types Telegraf has and the values on the right are the SQL types used when writing to SQLite.
  #[outputs.sql.convert]
  #  integer       = "INT"
  #  real          = "DOUBLE"
  #  text          = "TEXT"
  #  timestamp     = "TIMESTAMP"
  #  defaultvalue  = "TEXT"
  #  unsigned      = "UNSIGNED"
  #  bool          = "BOOL"

Input and output integration examples

Consul

1. Service Health Monitoring Dashboard: Utilize the Consul Input Plugin to create a comprehensive health monitoring dashboard for all services registered with Consul. This allows operations teams to visualize the health status in real time, enabling quick identification of service issues and facilitating rapid responses to service outages or performance degradation.

2. Automated Alerting System: Implement an automated alerting system that uses the health check data gathered by the Consul Input Plugin to trigger notifications whenever a service status changes to critical. This setup can integrate with notification systems like Slack or email, ensuring that team members are alerted immediately to address potential issues.

3. Integration with Incident Management: Leverage the health check data from the Consul Input Plugin to feed into incident management systems. By analyzing the health status trends, teams can prioritize incidents based on the criticality of the affected services and streamline their resolution processes, improving overall service reliability and customer satisfaction.

SQLite

1. Local Monitoring Storage: Configure the plugin to write metrics to a local SQLite database file. This is ideal for lightweight deployments where setting up a full-scale database server is not required.
2. Embedded Applications: Use SQLite as the backend for applications embedded in edge devices, benefiting from its file-based architecture and minimal resource requirements.
3. Quick Setup for Testing: Leverage SQLite’s ease of use to quickly set up a testing environment for Telegraf metrics collection without the need for external database services.
4. Custom Schema Management: Adjust the table creation templates to predefine your schema if you require specific column types or indexes, ensuring compatibility with your application’s needs.

Feedback

Thank you for being part of our community! If you have any general feedback or found any bugs on these pages, we welcome and encourage your input. Please submit your feedback in the InfluxDB community Slack.