Documentation
¶
Overview ¶
Package hive provides the infrastructure for building Cilium applications from modular components (cells).
Hive is implemented using the uber/dig library, which provides the dependency injection for objects in the hive. It is similar to uber/fx, but adds an opinionated approach to configuration.
The configuration for cells is extracted from Viper. By default the field names are assumed to correspond to flag names, e.g. field 'MyOption' corresponds to '--my-option' flag.
The hive constructor, New(), takes the viper instance and the pflag FlagSet as parameters and registers the flags from all cells and binds them to viper variables. Once the FlagSet and viper configuration has been parsed one can call Populate() to pull the values from viper and construct the application. The hive can then be Run().
Example ¶
For a runnable example see pkg/hive/example.
Try running:
example$ go run . (ctrl-c stops) example$ go run . --dot-graph | dot -Tx11
Try also commenting out cell.Provide lines and seeing what the dependency errors look like.
Index ¶
- func AddConfigOverride[Cfg cell.Flagger](h *Hive, override func(*Cfg))
- func RunRepl(h *Hive, in *os.File, out *os.File, prompt string)
- type ErrPopulate
- type Hive
- func (h *Hive) AppendInvoke(invoke func(*slog.Logger, time.Duration) error)
- func (h *Hive) Command() *cobra.Command
- func (h *Hive) Populate(log *slog.Logger) error
- func (h *Hive) PrintDotGraph() error
- func (h *Hive) PrintObjects(w io.Writer, log *slog.Logger) error
- func (h *Hive) RegisterFlags(flags *pflag.FlagSet)
- func (h *Hive) Run(log *slog.Logger, opts ...RunOptionFunc) error
- func (h *Hive) ScriptCommands(log *slog.Logger) (map[string]script.Cmd, error)
- func (h *Hive) Shutdown(opts ...ShutdownOption)
- func (h *Hive) Start(log *slog.Logger, ctx context.Context) error
- func (h *Hive) Stop(log *slog.Logger, ctx context.Context) error
- func (h *Hive) Viper() *viper.Viper
- type Metrics
- type NopMetrics
- type Options
- type RunOptionFunc
- type ScriptCmd
- type ScriptCmdOut
- type ScriptCmds
- type ScriptCmdsOut
- type ShutdownOption
- type Shutdowner
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func AddConfigOverride ¶
AddConfigOverride appends a config override function to modify a configuration after it has been parsed.
This method is only meant to be used in tests.
Types ¶
type ErrPopulate ¶
type ErrPopulate struct {
// contains filtered or unexported fields
}
func (ErrPopulate) Pretty ¶
func (e ErrPopulate) Pretty() string
type Hive ¶
type Hive struct {
// contains filtered or unexported fields
}
Hive is a framework building modular applications.
It implements dependency injection using the dig library.
See pkg/hive/example for a runnable example application.
func New ¶
New returns a new hive that can be run, or inspected. The command-line flags from the cells are registered as part of this.
The object graph is not constructed until methods of the hive are invoked.
Applications should call RegisterFlags() to register the hive's command-line flags. Likewise if configuration settings come from configuration files, then the Viper() method can be used to populate the hive's viper instance.
func (*Hive) AppendInvoke ¶
func (*Hive) Command ¶
Command constructs the cobra command for hive. The hive command can be used to inspect the dependency graph.
func (*Hive) Populate ¶
Populate instantiates the hive. Use for testing that the hive can be instantiated.
func (*Hive) PrintDotGraph ¶
func (*Hive) RegisterFlags ¶
RegisterFlags adds all flags in the hive to the given flag set. Fatals if a flag already exists in the given flag set. Use with e.g. cobra.Command:
cmd := &cobra.Command{...}
h.RegisterFlags(cmd.Flags())
func (*Hive) Run ¶
func (h *Hive) Run(log *slog.Logger, opts ...RunOptionFunc) error
Run populates the cell configurations and runs the hive cells. Interrupt signal or call to Shutdowner.Shutdown() will cause the hive to stop.
func (*Hive) ScriptCommands ¶
func (*Hive) Shutdown ¶
func (h *Hive) Shutdown(opts ...ShutdownOption)
Shutdown implements the Shutdowner interface and is provided for the cells to use for triggering a early shutdown.
func (*Hive) Start ¶
Start starts the hive. The context allows cancelling the start. If context is cancelled and the start hooks do not respect the cancellation then after 5 more seconds the process will be terminated forcefully.
type NopMetrics ¶ added in v1.0.1
type NopMetrics struct{}
func (NopMetrics) PopulateDuration ¶ added in v1.0.1
func (NopMetrics) PopulateDuration(duration time.Duration)
PopulateDuration implements Metrics.
func (NopMetrics) StartDuration ¶ added in v1.0.1
func (NopMetrics) StartDuration(duration time.Duration)
StartDuration implements Metrics.
func (NopMetrics) StopDuration ¶ added in v1.0.1
func (NopMetrics) StopDuration(duration time.Duration)
StopDuration implements Metrics.
type Options ¶
type Options struct {
// EnvPrefix is the prefix to use for environment variables, e.g.
// with prefix "CILIUM" the flag "foo" can be set with environment
// variable "CILIUM_FOO".
EnvPrefix string
// ModuleDecorator is an optional set of decorator functions to use for each
// module. This can be used to provide module-scoped overrides to objects.
// For example:
//
// opts.ModuleDecorators = cell.ModuleDecorators{
// func(foo Foo, id cell.ModuleID) Foo {
// return foo.With("moduleID", id)
// },
// }
//
// The above would give each cell within a module an augmented version of 'Foo'.
// The object that is being decorated (the return value) must already exist in
// the object graph.
ModuleDecorators cell.ModuleDecorators
// ModulePrivateProvider is an optional set of private provide functions to
// use for each module. This can be used to provide module-scoped objects.
// For example:
//
// opts.ModulePrivateProviders = cell.ModulePrivateProviders{
// func(id cell.ModuleID) Foo {
// return foo.New(id)
// },
// }
//
ModulePrivateProviders cell.ModulePrivateProviders
// DecodeHooks are optional additional decode hooks to use with cell.Config
// to decode a configuration flag into a config field. See existing hooks
// in [cell/config.go] for examples.
DecodeHooks cell.DecodeHooks
StartTimeout time.Duration
StopTimeout time.Duration
// LogThreshold is an optional threshold to reduce logging verbosity.
// When an Invoke or Lifecycle Start/Stop hook takes longer than this
// threshold, it will be logged at Info level. Otherwise it is logged
// at Debug level.
LogThreshold time.Duration
}
func DefaultOptions ¶
func DefaultOptions() Options
type RunOptionFunc ¶
type RunOptionFunc func(*Hive)
RunOptionFunc is a functional option type for configuring hive on Run stage.
func WithLogThreshold ¶
func WithLogThreshold(threshold time.Duration) RunOptionFunc
WithLogThreshold overrides hive LogThreshold option.
func WithStartTimeout ¶
func WithStartTimeout(timeout time.Duration) RunOptionFunc
WithStartTimeout overrides hive StartTimeout option.
func WithStopTimeout ¶
func WithStopTimeout(timeout time.Duration) RunOptionFunc
WithStopTimeout overrides hive StopTimeout option.
type ScriptCmdOut ¶
func NewScriptCmd ¶
func NewScriptCmd(name string, cmd script.Cmd) ScriptCmdOut
type ScriptCmds ¶
type ScriptCmdsOut ¶
func NewScriptCmds ¶
func NewScriptCmds(cmds map[string]script.Cmd) (out ScriptCmdsOut)
type ShutdownOption ¶
type ShutdownOption interface {
// contains filtered or unexported methods
}
func ShutdownWithError ¶
func ShutdownWithError(err error) ShutdownOption
ShutdownWithError shuts down with an error.
type Shutdowner ¶
type Shutdowner interface {
Shutdown(...ShutdownOption)
}
Shutdowner provides Shutdown(), which is a way to trigger stop for hive.
To shut down with an error, call Shutdown with ShutdownWithError(err). This error will be returned from Run().
Directories
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| Path | Synopsis |
|---|---|
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mini
command
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Package hivetest makes testing components using hive easier.
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Package hivetest makes testing components using hive easier. |
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Package script implements a small, customizable, platform-agnostic scripting language.
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Package script implements a small, customizable, platform-agnostic scripting language. |
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scripttest
Package scripttest adapts the script engine for use in tests.
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Package scripttest adapts the script engine for use in tests. |