68 lines
1.5 KiB
Go
68 lines
1.5 KiB
Go
package ln
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import (
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"context"
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"io"
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"sync"
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)
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// Filter interface for defining chain filters
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type Filter interface {
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Apply(ctx context.Context, e Event) bool
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Run()
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Close()
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}
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// FilterFunc allows simple functions to implement the Filter interface
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type FilterFunc func(ctx context.Context, e Event) bool
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// Apply implements the Filter interface
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func (ff FilterFunc) Apply(ctx context.Context, e Event) bool {
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return ff(ctx, e)
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}
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// Run implements the Filter interface
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func (ff FilterFunc) Run() {}
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// Close implements the Filter interface
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func (ff FilterFunc) Close() {}
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// WriterFilter implements a filter, which arbitrarily writes to an io.Writer
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type WriterFilter struct {
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sync.Mutex
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Out io.Writer
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Formatter Formatter
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}
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// NewWriterFilter creates a filter to add to the chain
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func NewWriterFilter(out io.Writer, format Formatter) *WriterFilter {
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if format == nil {
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format = DefaultFormatter
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}
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return &WriterFilter{
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Out: out,
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Formatter: format,
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}
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}
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// Apply implements the Filter interface
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func (w *WriterFilter) Apply(ctx context.Context, e Event) bool {
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output, err := w.Formatter.Format(ctx, e)
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if err == nil {
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w.Lock()
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w.Out.Write(output)
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w.Unlock()
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}
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return true
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}
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// Run implements the Filter interface
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func (w *WriterFilter) Run() {}
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// Close implements the Filter interface
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func (w *WriterFilter) Close() {}
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// NilFilter is safe to return as a Filter, but does nothing
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var NilFilter = FilterFunc(func(_ context.Context, e Event) bool { return true })
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