mirror of
https://github.com/open-policy-agent/opa.git
synced 2026-08-15 12:52:44 -06:00
Philip Conrad
c5706eef7c
This commit introduces a few major changes: - (Breaking change) Limits now exist for maximum request body sizes. - Buffers are preallocated for reading request bodies. - Buffers are preallocated for decompressing request bodies. - Gzip decoder instances are reused in a `sync.Pool` across requests. The effect on garbage collection is dramatically fewer GC pauses, giving a roughly 9% RPS improvement in load tests with gzipped request bodies. For larger request sizes, the number of GC pauses is dramatically reduced, although the peak pause time may increase by a few percent. Implementation notes: - The DecodingLimits handler enforces the max request body size both through a Content-Length check, and a MaxBytesReader wrapper around the payload. - The DecodingLimits handler passes the gzip payload size limit down using a context key. Signed-off-by: Philip Conrad <philipaconrad@gmail.com>
103 lines
3.1 KiB
Go
103 lines
3.1 KiB
Go
// Package decoding implements the configuration side of the upgraded gzip
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// decompression framework. The original work only enabled gzip decoding for
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// a few endpoints-- here we enable if for all of OPA. Additionally, we provide
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// some new defensive configuration options: max_length, and gzip.max_length.
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// These allow rejecting requests that indicate their contents are larger than
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// the size limits.
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//
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// The request handling pipeline now looks roughly like this:
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//
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// Request -> MaxBytesReader(Config.MaxLength) -> ir.CopyN(dest, req, Gzip.MaxLength)
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//
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// The intent behind this design is to improve how OPA handles large and/or
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// malicious requests, compressed or otherwise. The benefit of being a little
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// more strict in what we allow is that we can now use "riskier", but
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// dramatically more performant techniques, like preallocating content buffers
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// for gzipped data. This also should help OPAs in limited memory situations.
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package decoding
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import (
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"fmt"
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"github.com/open-policy-agent/opa/util"
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)
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var (
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defaultMaxRequestLength = int64(268435456) // 256 MB
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defaultGzipMaxContentLength = int64(536870912) // 512 MB
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)
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// Config represents the configuration for the Server.Decoding settings
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type Config struct {
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MaxLength *int64 `json:"max_length,omitempty"` // maximum request size that will be read, regardless of compression.
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Gzip *Gzip `json:"gzip,omitempty"`
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}
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// Gzip represents the configuration for the Server.Decoding.Gzip settings
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type Gzip struct {
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MaxLength *int64 `json:"max_length,omitempty"` // Max number of bytes allowed to be read from the decompressor.
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}
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// ConfigBuilder assists in the construction of the plugin configuration.
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type ConfigBuilder struct {
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raw []byte
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}
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// NewConfigBuilder returns a new ConfigBuilder to build and parse the server config
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func NewConfigBuilder() *ConfigBuilder {
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return &ConfigBuilder{}
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}
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// WithBytes sets the raw server config
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func (b *ConfigBuilder) WithBytes(config []byte) *ConfigBuilder {
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b.raw = config
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return b
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}
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// Parse returns a valid Config object with defaults injected.
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func (b *ConfigBuilder) Parse() (*Config, error) {
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if b.raw == nil {
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defaultConfig := &Config{
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MaxLength: &defaultMaxRequestLength,
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Gzip: &Gzip{
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MaxLength: &defaultGzipMaxContentLength,
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},
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}
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return defaultConfig, nil
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}
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var result Config
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if err := util.Unmarshal(b.raw, &result); err != nil {
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return nil, err
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}
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return &result, result.validateAndInjectDefaults()
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}
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// validateAndInjectDefaults populates defaults if the fields are nil, then
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// validates the config values.
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func (c *Config) validateAndInjectDefaults() error {
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if c.MaxLength == nil {
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c.MaxLength = &defaultMaxRequestLength
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}
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if c.Gzip == nil {
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c.Gzip = &Gzip{
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MaxLength: &defaultGzipMaxContentLength,
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}
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}
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if c.Gzip.MaxLength == nil {
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c.Gzip.MaxLength = &defaultGzipMaxContentLength
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}
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if *c.MaxLength <= 0 {
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return fmt.Errorf("invalid value for server.decoding.max_length field, should be a positive number")
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}
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if *c.Gzip.MaxLength <= 0 {
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return fmt.Errorf("invalid value for server.decoding.gzip.max_length field, should be a positive number")
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}
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return nil
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}
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