mirror of
https://github.com/open-policy-agent/opa.git
synced 2026-08-12 19:32:48 -06:00
Ashutosh Narkar
0be08fd04a
Earlier the downloader package only supported the http short polling technique where the client sends periodic requests to the server to fetch bundles. A drawback of this method is that a low polling frequency could add unnecessary burden on the server and network. This commit adds support for http long polling which helps to minimize server/network resource usage and also reduces the delay in delivery of updates to the client. Signed-off-by: Ashutosh Narkar <anarkar4387@gmail.com>
64 lines
2.2 KiB
Go
64 lines
2.2 KiB
Go
// Copyright 2018 The OPA Authors. All rights reserved.
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// Use of this source code is governed by an Apache2
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// license that can be found in the LICENSE file.
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package download
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import (
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"fmt"
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"time"
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)
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const (
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defaultMinDelaySeconds = int64(60)
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defaultMaxDelaySeconds = int64(120)
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)
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// PollingConfig represents polling configuration for the downloader.
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type PollingConfig struct {
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MinDelaySeconds *int64 `json:"min_delay_seconds,omitempty"` // min amount of time to wait between successful poll attempts
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MaxDelaySeconds *int64 `json:"max_delay_seconds,omitempty"` // max amount of time to wait between poll attempts
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LongPollingTimeoutSeconds *int64 `json:"long_polling_timeout_seconds,omitempty"` // max amount of time the server should wait before issuing a timeout if there's no update available
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}
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// Config represents the configuration for the downloader.
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type Config struct {
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Polling PollingConfig `json:"polling"`
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}
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// ValidateAndInjectDefaults checks for configuration errors and ensures all
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// values are set on the Config object.
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func (c *Config) ValidateAndInjectDefaults() error {
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min := defaultMinDelaySeconds
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max := defaultMaxDelaySeconds
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// reject bad min/max values
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if c.Polling.MaxDelaySeconds != nil && c.Polling.MinDelaySeconds != nil {
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if *c.Polling.MaxDelaySeconds < *c.Polling.MinDelaySeconds {
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return fmt.Errorf("max polling delay must be >= min polling delay")
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}
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min = *c.Polling.MinDelaySeconds
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max = *c.Polling.MaxDelaySeconds
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} else if c.Polling.MaxDelaySeconds == nil && c.Polling.MinDelaySeconds != nil {
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return fmt.Errorf("polling configuration missing 'max_delay_seconds'")
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} else if c.Polling.MinDelaySeconds == nil && c.Polling.MaxDelaySeconds != nil {
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return fmt.Errorf("polling configuration missing 'min_delay_seconds'")
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}
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// scale to seconds
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minSeconds := int64(time.Duration(min) * time.Second)
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c.Polling.MinDelaySeconds = &minSeconds
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maxSeconds := int64(time.Duration(max) * time.Second)
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c.Polling.MaxDelaySeconds = &maxSeconds
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if c.Polling.LongPollingTimeoutSeconds != nil {
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if *c.Polling.LongPollingTimeoutSeconds < 1 {
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return fmt.Errorf("'long_polling_timeout_seconds' must be at least 1")
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}
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}
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return nil
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}
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