martin-helmich/prometheus-nginxlog-exporter

package config

import (
    "fmt"
    "io"
    "os"
    "strings"

    "github.com/martin-helmich/prometheus-nginxlog-exporter/log"
)

// FileFormat describes which kind of configuration file the exporter was started with
type FileFormat int

const (
    // TypeHCL describes the HCL (Hashicorp configuration language) file format
    TypeHCL FileFormat = iota
    // TypeYAML describes the YAML file format
    TypeYAML
)

// LoadConfigFromFile fills a configuration object (passed as parameter) with
// values read from a configuration file (pass as parameter by filename). The
// configuration file needs to be in HCL format.
func LoadConfigFromFile(logger *log.Logger, config *Config, filename string) error {
    var typ FileFormat

    reader, err := os.Open(filename)
    if err != nil {
        return err
    }

    defer reader.Close()

    if strings.HasSuffix(filename, ".hcl") {
        typ = TypeHCL
    } else if strings.HasSuffix(filename, ".yaml") || strings.HasSuffix(filename, ".yml") {
        typ = TypeYAML
    } else {
        return fmt.Errorf("config file '%s' has unsupported file type", filename)
    }

    return LoadConfigFromStream(logger, config, reader, typ)
}

// LoadConfigFromStream fills a configuration object (passed as parameter) with
// values read from a Reader interface (passed as parameter).
func LoadConfigFromStream(logger *log.Logger, config *Config, stream io.Reader, typ FileFormat) error {
    switch typ {
    case TypeHCL:
        if err := loadConfigFromHCLStream(config, stream); err != nil {
            return err
        }
    case TypeYAML:
        if err := loadConfigFromYAMLStream(config, stream); err != nil {
            return err
        }
    default:
        return fmt.Errorf("unsupported config type %d", typ)
    }

    for i := range config.Namespaces {
        config.Namespaces[i].ResolveDeprecations()

        if err := config.Namespaces[i].ResolveGlobs(logger); err != nil {
            return err
        }
    }

    return nil
}