feat: adds configuration file support.

README.md

@@ -44,6 +44,21 @@ To abort tailing, hit `Ctrl+C`.
 
 Run `ktail -h` for usage.
 
+## Configuration
+
+Ktail will read the file `$HOME/.config/ktail/config.yml` if it exists. This must be a file in YAML format. The following options can be set (these are the defaults):
+
+```yaml
+noColor: false
+raw: false
+timestamps: false
+quiet: false
+colorScheme: bw
+colorMode: auto
+kubeConfigPath: ""
+templateString: ""
+```
+
 ## Templating
 
 ktail has a basic output format. To override, you can use a simple Go template. For example:

config.go

@@ -0,0 +1,43 @@
+package main
+
+import (
+ "fmt"
+ "os"
+ "path/filepath"
+
+ "k8s.io/apimachinery/pkg/util/yaml"
+)
+
+type Config struct {
+ Quiet bool `yaml:"quiet"`
+ NoColor bool `yaml:"noColor"`
+ Raw bool `yaml:"raw"`
+ Timestamps bool `yaml:"timestamps"`
+ ColorMode string `yaml:"colorMode"`
+ ColorScheme string `yaml:"colorScheme"`
+ TemplateString string `yaml:"templateString"`
+ KubeConfigPath string `yaml:"kubeConfigPath"`
+}
+
+func (c *Config) LoadDefault() error {
+ home := os.Getenv("HOME")
+ if home == "" {
+ return nil
+ }
+ if err := c.LoadFromPath(filepath.Join(home, ".config", "ktail", "config.yml")); err != nil &&
+ !os.IsNotExist(err) {
+ return err
+ }
+ return nil
+}
+
+func (c *Config) LoadFromPath(path string) error {
+ data, err := os.ReadFile(path)
+ if err != nil {
+ return err
+ }
+ if err := yaml.UnmarshalStrict(data, c); err != nil {
+ return fmt.Errorf("parsing config file %q: %w", path, err)
+ }
+ return nil
+}

main.go

@@ -25,17 +25,21 @@ import (
  "k8s.io/klog/v2"
 )
 
-const defaultColorScheme = "bw"
-
 func main() {
  klog.SetLogger(logr.New(&kubeLogger{}))
 
+ cfg := Config{
+ ColorMode: "auto",
+ ColorScheme: "bw",
+ }
+
  var (
- contextName string
+ contextName string
+ labelSelectorExpr string
+ namespaces []string
+ allNamespaces bool
+
  kubeconfigPath string
- labelSelectorExpr string
- namespaces []string
- allNamespaces bool
  quiet bool
  timestamps bool
  raw bool
@@ -49,36 +53,41 @@ func main() {
  colorScheme string
  )
 
+ if err := cfg.LoadDefault(); err != nil {
+ fail(err.Error())
+ }
+
  flags := pflag.NewFlagSet("ktail", pflag.ContinueOnError)
  flags.SortFlags = false
  flags.Usage = func() {
  fmt.Printf("Usage: ktail [OPTION ...] PATTERN [PATTERN ...]\n")
  flags.PrintDefaults()
  }
  flags.StringVar(&contextName, "context", "", "Kubernetes context name")
- flags.StringVar(&kubeconfigPath, "kubeconfig", "",
- "Path to kubeconfig (only required out-of-cluster)")
  flags.StringArrayVarP(&namespaces, "namespace", "n", []string{}, "Kubernetes namespace")
  flags.BoolVar(&allNamespaces, "all-namespaces", false, "Apply to all Kubernetes namespaces")
  flags.StringArrayVarP(&excludePatternStrings, "exclude", "x", []string{},
  "Exclude using a regular expression. Pattern can be repeated. Takes priority over"+
  " include patterns and labels.")
  flags.StringVarP(&labelSelectorExpr, "selector", "l", "",
  "Match pods by label (see 'kubectl get -h' for syntax).")
- flags.StringVarP(&tmplString, "template", "t", "",
- "Template to format each line. For example, for"+
- " just the message, use --template '{{ .Message }}'.")
- flags.BoolVarP(&raw, "raw", "r", false, "Don't format output; output messages only (unless --timestamps)")
- flags.BoolVarP(&timestamps, "timestamps", "T", false, "Include timestamps on each line")
- flags.BoolVarP(&quiet, "quiet", "q", false, "Don't print events about new/deleted pods")
  flags.BoolVarP(&sinceStart, "since-start", "s", false,
  "Start reading log from the beginning of the container's lifetime.")
  flags.BoolVarP(&showVersion, "version", "", false, "Show version.")
- flags.BoolVar(&noColor, "no-color", false, "Alias for --color=never.")
- flags.StringVar(&colorMode, "color", "auto", "Set color mode: one of 'auto' (default), 'never', or 'always'. (Aliased as --colour.)")
- flags.StringVar(&colorMode, "colour", "auto", "Set color mode: one of 'auto' (default), 'never', or 'always'.")
- flags.StringVar(&colorScheme, "color-scheme", defaultColorScheme, "Set color scheme (see https://github.com/alecthomas/chroma/tree/master/styles). (Aliased as --colour-scheme.)")
- flags.StringVar(&colorScheme, "colour-scheme", defaultColorScheme, "Set color scheme (see https://github.com/alecthomas/chroma/tree/master/styles).")
+
+ flags.StringVar(&kubeconfigPath, "kubeconfig", cfg.KubeConfigPath,
+ "Path to kubeconfig (only required out-of-cluster)")
+ flags.StringVarP(&tmplString, "template", "t", cfg.TemplateString,
+ "Template to format each line. For example, for"+
+ " just the message, use --template '{{ .Message }}'.")
+ flags.BoolVarP(&raw, "raw", "r", cfg.Raw, "Don't format output; output messages only (unless --timestamps)")
+ flags.BoolVarP(&timestamps, "timestamps", "T", cfg.Timestamps, "Include timestamps on each line")
+ flags.BoolVarP(&quiet, "quiet", "q", cfg.Quiet, "Don't print events about new/deleted pods")
+ flags.BoolVar(&noColor, "no-color", cfg.NoColor, "Alias for --color=never.")
+ flags.StringVar(&colorMode, "color", cfg.ColorMode, "Set color mode: one of 'auto' (default), 'never', or 'always'. (Aliased as --colour.)")
+ flags.StringVar(&colorMode, "colour", cfg.ColorMode, "Set color mode: one of 'auto' (default), 'never', or 'always'.")
+ flags.StringVar(&colorScheme, "color-scheme", cfg.ColorScheme, "Set color scheme (see https://github.com/alecthomas/chroma/tree/master/styles). (Aliased as --colour-scheme.)")
+ flags.StringVar(&colorScheme, "colour-scheme", cfg.ColorScheme, "Set color scheme (see https://github.com/alecthomas/chroma/tree/master/styles).")
  _ = flags.MarkHidden("colour")
  _ = flags.MarkHidden("colour-scheme")
 
@@ -87,7 +96,6 @@ func main() {
  os.Exit(2)
  }
  fail(err.Error())
- os.Exit(1)
  }
 
  if noColor {