cmd/icingadb: if --config-from-env given, load config from env vars

go.mod

@@ -3,6 +3,7 @@ module github.com/icinga/icingadb
 go 1.22
 
 require (
+	github.com/caarlos0/env/v11 v11.0.1
 	github.com/creasty/defaults v1.7.0
 	github.com/go-sql-driver/mysql v1.8.1
 	github.com/goccy/go-yaml v1.11.3

go.sum

@@ -8,6 +8,8 @@ github.com/bsm/ginkgo/v2 v2.12.0 h1:Ny8MWAHyOepLGlLKYmXG4IEkioBysk6GpaRTLC8zwWs=
 github.com/bsm/ginkgo/v2 v2.12.0/go.mod h1:SwYbGRRDovPVboqFv0tPTcG1sN61LM1Z4ARdbAV9g4c=
 github.com/bsm/gomega v1.27.10 h1:yeMWxP2pV2fG3FgAODIY8EiRE3dy0aeFYt4l7wh6yKA=
 github.com/bsm/gomega v1.27.10/go.mod h1:JyEr/xRbxbtgWNi8tIEVPUYZ5Dzef52k01W3YH0H+O0=
+github.com/caarlos0/env/v11 v11.0.1 h1:A8dDt9Ub9ybqRSUF3fQc/TA/gTam2bKT4Pit+cwrsPs=
+github.com/caarlos0/env/v11 v11.0.1/go.mod h1:2RC3HQu8BQqtEK3V4iHPxj0jOdWdbPpWJ6pOueeU1xM=
 github.com/cespare/xxhash/v2 v2.2.0 h1:DC2CZ1Ep5Y4k3ZQ899DldepgrayRUGE6BBZ/cd9Cj44=
 github.com/cespare/xxhash/v2 v2.2.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/creasty/defaults v1.7.0 h1:eNdqZvc5B509z18lD8yc212CAqJNvfT1Jq6L8WowdBA=

internal/command/command.go

@@ -35,7 +35,13 @@ func New() *Command {
 		os.Exit(0)
 	}
 
-	cfg, err := config.FromYAMLFile(flags.Config)
+	var cfg *config.Config
+	if flags.ConfigFromEnv {
+		cfg, err = config.FromEnv()
+	} else {
+		cfg, err = config.FromYAMLFile(flags.Config)
+	}
+
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(2)

pkg/config/config.go

@@ -3,6 +3,7 @@ package config
 import (
 	"crypto/tls"
 	"crypto/x509"
+	"github.com/caarlos0/env/v11"
 	"github.com/creasty/defaults"
 	"github.com/goccy/go-yaml"
 	"github.com/jessevdk/go-flags"
@@ -12,10 +13,10 @@ import (
 
 // Config defines Icinga DB config.
 type Config struct {
-	Database  Database  `yaml:"database"`
-	Redis     Redis     `yaml:"redis"`
-	Logging   Logging   `yaml:"logging"`
-	Retention Retention `yaml:"retention"`
+	Database  Database  `yaml:"database" envPrefix:"DATABASE_"`
+	Redis     Redis     `yaml:"redis" envPrefix:"REDIS_"`
+	Logging   Logging   `yaml:"logging" envPrefix:"LOGGING_"`
+	Retention Retention `yaml:"retention" envPrefix:"RETENTION_"`
 }
 
 // Validate checks constraints in the supplied configuration and returns an error if they are violated.
@@ -40,6 +41,8 @@ func (c *Config) Validate() error {
 type Flags struct {
 	// Version decides whether to just print the version and exit.
 	Version bool `long:"version" description:"print version and exit"`
+	// ConfigFromEnv decides whether to load the config from environment variables.
+	ConfigFromEnv bool `long:"config-from-env" description:"load config from env vars"`
 	// Config is the path to the config file
 	Config string `short:"c" long:"config" description:"path to config file" required:"true" default:"/etc/icingadb/config.yml"`
 }
@@ -70,6 +73,25 @@ func FromYAMLFile(name string) (*Config, error) {
 	return c, nil
 }
 
+// FromEnv returns a new Config value created from environment variables.
+func FromEnv() (*Config, error) {
+	c := &Config{}
+
+	if err := defaults.Set(c); err != nil {
+		return nil, errors.Wrap(err, "can't set config defaults")
+	}
+
+	if err := env.ParseWithOptions(c, env.Options{Prefix: "ICINGADB_"}); err != nil {
+		return nil, errors.Wrap(err, "can't parse env vars")
+	}
+
+	if err := c.Validate(); err != nil {
+		return nil, errors.Wrap(err, "invalid configuration")
+	}
+
+	return c, nil
+}
+
 // ParseFlags parses CLI flags and
 // returns a Flags value created from them.
 func ParseFlags() (*Flags, error) {
@@ -85,11 +107,11 @@ func ParseFlags() (*Flags, error) {
 
 // TLS provides TLS configuration options for Redis and Database.
 type TLS struct {
-	Enable   bool   `yaml:"tls"`
-	Cert     string `yaml:"cert"`
-	Key      string `yaml:"key"`
-	Ca       string `yaml:"ca"`
-	Insecure bool   `yaml:"insecure"`
+	Enable   bool   `yaml:"tls" env:"TLS"`
+	Cert     string `yaml:"cert" env:"CERT"`
+	Key      string `yaml:"key" env:"KEY"`
+	Ca       string `yaml:"ca" env:"CA"`
+	Insecure bool   `yaml:"insecure" env:"INSECURE"`
 }
 
 // MakeConfig assembles a tls.Config from t and serverName.

pkg/config/database.go

@@ -22,14 +22,14 @@ import (
 
 // Database defines database client configuration.
 type Database struct {
-	Type       string           `yaml:"type" default:"mysql"`
-	Host       string           `yaml:"host"`
-	Port       int              `yaml:"port"`
-	Database   string           `yaml:"database"`
-	User       string           `yaml:"user"`
-	Password   string           `yaml:"password"`
+	Type       string           `yaml:"type" env:"TYPE" default:"mysql"`
+	Host       string           `yaml:"host" env:"HOST"`
+	Port       int              `yaml:"port" env:"PORT"`
+	Database   string           `yaml:"database" env:"DATABASE"`
+	User       string           `yaml:"user" env:"USER"`
+	Password   string           `yaml:"password" env:"PASSWORD"`
 	TlsOptions TLS              `yaml:",inline"`
-	Options    icingadb.Options `yaml:"options"`
+	Options    icingadb.Options `yaml:"options" envPrefix:"OPTIONS_"`
 }
 
 // Open prepares the DSN string and driver configuration,

pkg/config/history_retention.go

@@ -8,11 +8,11 @@ import (
 
 // Retention defines configuration for history retention.
 type Retention struct {
-	HistoryDays uint64                   `yaml:"history-days"`
-	SlaDays     uint64                   `yaml:"sla-days"`
-	Interval    time.Duration            `yaml:"interval" default:"1h"`
-	Count       uint64                   `yaml:"count" default:"5000"`
-	Options     history.RetentionOptions `yaml:"options"`
+	HistoryDays uint64                   `yaml:"history-days" env:"HISTORY_DAYS"`
+	SlaDays     uint64                   `yaml:"sla-days" env:"SLA_DAYS"`
+	Interval    time.Duration            `yaml:"interval" env:"INTERVAL" default:"1h"`
+	Count       uint64                   `yaml:"count" env:"COUNT" default:"5000"`
+	Options     history.RetentionOptions `yaml:"options" env:"OPTIONS"`
 }
 
 // Validate checks constraints in the supplied retention configuration and

pkg/config/logging.go

@@ -11,12 +11,12 @@ import (
 // Logging defines Logger configuration.
 type Logging struct {
 	// zapcore.Level at 0 is for info level.
-	Level  zapcore.Level `yaml:"level" default:"0"`
-	Output string        `yaml:"output"`
+	Level  zapcore.Level `yaml:"level" env:"LEVEL" default:"0"`
+	Output string        `yaml:"output" env:"OUTPUT"`
 	// Interval for periodic logging.
-	Interval time.Duration `yaml:"interval" default:"20s"`
+	Interval time.Duration `yaml:"interval" env:"INTERVAL" default:"20s"`
 
-	logging.Options `yaml:"options"`
+	logging.Options `yaml:"options" env:"OPTIONS"`
 }
 
 // Validate checks constraints in the supplied Logging configuration and returns an error if they are violated.

pkg/config/redis.go

@@ -19,11 +19,11 @@ import (
 
 // Redis defines Redis client configuration.
 type Redis struct {
-	Host       string              `yaml:"host"`
-	Port       int                 `yaml:"port" default:"6380"`
-	Password   string              `yaml:"password"`
+	Host       string              `yaml:"host" env:"HOST"`
+	Port       int                 `yaml:"port" env:"PORT" default:"6380"`
+	Password   string              `yaml:"password" env:"PASSWORD"`
 	TlsOptions TLS                 `yaml:",inline"`
-	Options    icingaredis.Options `yaml:"options"`
+	Options    icingaredis.Options `yaml:"options" envPrefix:"OPTIONS_"`
 }
 
 type ctxDialerFunc = func(ctx context.Context, network, addr string) (net.Conn, error)

pkg/icingadb/db.go

@@ -37,29 +37,29 @@ type DB struct {
 // Options define user configurable database options.
 type Options struct {
 	// Maximum number of open connections to the database.
-	MaxConnections int `yaml:"max_connections" default:"16"`
+	MaxConnections int `yaml:"max_connections" env:"MAX_CONNECTIONS" default:"16"`
 
 	// Maximum number of connections per table,
 	// regardless of what the connection is actually doing,
 	// e.g. INSERT, UPDATE, DELETE.
-	MaxConnectionsPerTable int `yaml:"max_connections_per_table" default:"8"`
+	MaxConnectionsPerTable int `yaml:"max_connections_per_table" env:"MAX_CONNECTIONS_PER_TABLE" default:"8"`
 
 	// MaxPlaceholdersPerStatement defines the maximum number of placeholders in an
 	// INSERT, UPDATE or DELETE statement. Theoretically, MySQL can handle up to 2^16-1 placeholders,
 	// but this increases the execution time of queries and thus reduces the number of queries
 	// that can be executed in parallel in a given time.
 	// The default is 2^13, which in our tests showed the best performance in terms of execution time and parallelism.
-	MaxPlaceholdersPerStatement int `yaml:"max_placeholders_per_statement" default:"8192"`
+	MaxPlaceholdersPerStatement int `yaml:"max_placeholders_per_statement" env:"MAX_PLACEHOLDERS_PER_STATEMENT" default:"8192"`
 
 	// MaxRowsPerTransaction defines the maximum number of rows per transaction.
 	// The default is 2^13, which in our tests showed the best performance in terms of execution time and parallelism.
-	MaxRowsPerTransaction int `yaml:"max_rows_per_transaction" default:"8192"`
+	MaxRowsPerTransaction int `yaml:"max_rows_per_transaction" env:"MAX_ROWS_PER_TRANSACTION" default:"8192"`
 
 	// WsrepSyncWait enforces Galera cluster nodes to perform strict cluster-wide causality checks
 	// before executing specific SQL queries determined by the number you provided.
 	// Please refer to the below link for a detailed description.
 	// https://icinga.com/docs/icinga-db/latest/doc/03-Configuration/#galera-cluster
-	WsrepSyncWait int `yaml:"wsrep_sync_wait" default:"7"`
+	WsrepSyncWait int `yaml:"wsrep_sync_wait" env:"WSREP_SYNC_WAIT" default:"7"`
 }
 
 // Validate checks constraints in the supplied database options and returns an error if they are violated.

pkg/icingaredis/client.go

@@ -28,12 +28,12 @@ type Client struct {
 
 // Options define user configurable Redis options.
 type Options struct {
-	BlockTimeout        time.Duration `yaml:"block_timeout"         default:"1s"`
-	HMGetCount          int           `yaml:"hmget_count"           default:"4096"`
-	HScanCount          int           `yaml:"hscan_count"           default:"4096"`
-	MaxHMGetConnections int           `yaml:"max_hmget_connections" default:"8"`
-	Timeout             time.Duration `yaml:"timeout"               default:"30s"`
-	XReadCount          int           `yaml:"xread_count"           default:"4096"`
+	BlockTimeout        time.Duration `yaml:"block_timeout" env:"BLOCK_TIMEOUT" default:"1s"`
+	HMGetCount          int           `yaml:"hmget_count" env:"HMGET_COUNT" default:"4096"`
+	HScanCount          int           `yaml:"hscan_count" env:"HSCAN_COUNT" default:"4096"`
+	MaxHMGetConnections int           `yaml:"max_hmget_connections" env:"MAX_HMGET_CONNECTIONS" default:"8"`
+	Timeout             time.Duration `yaml:"timeout" env:"TIMEOUT" default:"30s"`
+	XReadCount          int           `yaml:"xread_count" env:"XREAD_COUNT" default:"4096"`
 }
 
 // Validate checks constraints in the supplied Redis options and returns an error if they are violated.