diff options
Diffstat (limited to 'vendor/github.com/Azure/azure-pipeline-go/pipeline/core.go')
-rwxr-xr-x | vendor/github.com/Azure/azure-pipeline-go/pipeline/core.go | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/vendor/github.com/Azure/azure-pipeline-go/pipeline/core.go b/vendor/github.com/Azure/azure-pipeline-go/pipeline/core.go new file mode 100755 index 000000000..0dde81d72 --- /dev/null +++ b/vendor/github.com/Azure/azure-pipeline-go/pipeline/core.go @@ -0,0 +1,255 @@ +package pipeline + +import ( + "context" + "net" + "net/http" + "os" + "time" +) + +// The Factory interface represents an object that can create its Policy object. Each HTTP request sent +// requires that this Factory create a new instance of its Policy object. +type Factory interface { + New(next Policy, po *PolicyOptions) Policy +} + +// FactoryFunc is an adapter that allows the use of an ordinary function as a Factory interface. +type FactoryFunc func(next Policy, po *PolicyOptions) PolicyFunc + +// New calls f(next,po). +func (f FactoryFunc) New(next Policy, po *PolicyOptions) Policy { + return f(next, po) +} + +// The Policy interface represents a mutable Policy object created by a Factory. The object can mutate/process +// the HTTP request and then forward it on to the next Policy object in the linked-list. The returned +// Response goes backward through the linked-list for additional processing. +// NOTE: Request is passed by value so changes do not change the caller's version of +// the request. However, Request has some fields that reference mutable objects (not strings). +// These references are copied; a deep copy is not performed. Specifically, this means that +// you should avoid modifying the objects referred to by these fields: URL, Header, Body, +// GetBody, TransferEncoding, Form, MultipartForm, Trailer, TLS, Cancel, and Response. +type Policy interface { + Do(ctx context.Context, request Request) (Response, error) +} + +// PolicyFunc is an adapter that allows the use of an ordinary function as a Policy interface. +type PolicyFunc func(ctx context.Context, request Request) (Response, error) + +// Do calls f(ctx, request). +func (f PolicyFunc) Do(ctx context.Context, request Request) (Response, error) { + return f(ctx, request) +} + +// Options configures a Pipeline's behavior. +type Options struct { + HTTPSender Factory // If sender is nil, then the pipeline's default client is used to send the HTTP requests. + Log LogOptions +} + +// LogLevel tells a logger the minimum level to log. When code reports a log entry, +// the LogLevel indicates the level of the log entry. The logger only records entries +// whose level is at least the level it was told to log. See the Log* constants. +// For example, if a logger is configured with LogError, then LogError, LogPanic, +// and LogFatal entries will be logged; lower level entries are ignored. +type LogLevel uint32 + +const ( + // LogNone tells a logger not to log any entries passed to it. + LogNone LogLevel = iota + + // LogFatal tells a logger to log all LogFatal entries passed to it. + LogFatal + + // LogPanic tells a logger to log all LogPanic and LogFatal entries passed to it. + LogPanic + + // LogError tells a logger to log all LogError, LogPanic and LogFatal entries passed to it. + LogError + + // LogWarning tells a logger to log all LogWarning, LogError, LogPanic and LogFatal entries passed to it. + LogWarning + + // LogInfo tells a logger to log all LogInfo, LogWarning, LogError, LogPanic and LogFatal entries passed to it. + LogInfo + + // LogDebug tells a logger to log all LogDebug, LogInfo, LogWarning, LogError, LogPanic and LogFatal entries passed to it. + LogDebug +) + +// LogOptions configures the pipeline's logging mechanism & level filtering. +type LogOptions struct { + Log func(level LogLevel, message string) + + // ShouldLog is called periodically allowing you to return whether the specified LogLevel should be logged or not. + // An application can return different values over the its lifetime; this allows the application to dynamically + // alter what is logged. NOTE: This method can be called by multiple goroutines simultaneously so make sure + // you implement it in a goroutine-safe way. If nil, nothing is logged (the equivalent of returning LogNone). + // Usually, the function will be implemented simply like this: return level <= LogWarning + ShouldLog func(level LogLevel) bool +} + +type pipeline struct { + factories []Factory + options Options +} + +// The Pipeline interface represents an ordered list of Factory objects and an object implementing the HTTPSender interface. +// You construct a Pipeline by calling the pipeline.NewPipeline function. To send an HTTP request, call pipeline.NewRequest +// and then call Pipeline's Do method passing a context, the request, and a method-specific Factory (or nil). Passing a +// method-specific Factory allows this one call to Do to inject a Policy into the linked-list. The policy is injected where +// the MethodFactoryMarker (see the pipeline.MethodFactoryMarker function) is in the slice of Factory objects. +// +// When Do is called, the Pipeline object asks each Factory object to construct its Policy object and adds each Policy to a linked-list. +// THen, Do sends the Context and Request through all the Policy objects. The final Policy object sends the request over the network +// (via the HTTPSender object passed to NewPipeline) and the response is returned backwards through all the Policy objects. +// Since Pipeline and Factory objects are goroutine-safe, you typically create 1 Pipeline object and reuse it to make many HTTP requests. +type Pipeline interface { + Do(ctx context.Context, methodFactory Factory, request Request) (Response, error) +} + +// NewPipeline creates a new goroutine-safe Pipeline object from the slice of Factory objects and the specified options. +func NewPipeline(factories []Factory, o Options) Pipeline { + if o.HTTPSender == nil { + o.HTTPSender = newDefaultHTTPClientFactory() + } + if o.Log.Log == nil { + o.Log.Log = func(LogLevel, string) {} // No-op logger + } + return &pipeline{factories: factories, options: o} +} + +// Do is called for each and every HTTP request. It tells each Factory to create its own (mutable) Policy object +// replacing a MethodFactoryMarker factory (if it exists) with the methodFactory passed in. Then, the Context and Request +// are sent through the pipeline of Policy objects (which can transform the Request's URL/query parameters/headers) and +// ultimately sends the transformed HTTP request over the network. +func (p *pipeline) Do(ctx context.Context, methodFactory Factory, request Request) (Response, error) { + response, err := p.newPolicies(methodFactory).Do(ctx, request) + request.close() + return response, err +} + +func (p *pipeline) newPolicies(methodFactory Factory) Policy { + // The last Policy is the one that actually sends the request over the wire and gets the response. + // It is overridable via the Options' HTTPSender field. + po := &PolicyOptions{pipeline: p} // One object shared by all policy objects + next := p.options.HTTPSender.New(nil, po) + + // Walk over the slice of Factory objects in reverse (from wire to API) + markers := 0 + for i := len(p.factories) - 1; i >= 0; i-- { + factory := p.factories[i] + if _, ok := factory.(methodFactoryMarker); ok { + markers++ + if markers > 1 { + panic("MethodFactoryMarker can only appear once in the pipeline") + } + if methodFactory != nil { + // Replace MethodFactoryMarker with passed-in methodFactory + next = methodFactory.New(next, po) + } + } else { + // Use the slice's Factory to construct its Policy + next = factory.New(next, po) + } + } + + // Each Factory has created its Policy + if markers == 0 && methodFactory != nil { + panic("Non-nil methodFactory requires MethodFactoryMarker in the pipeline") + } + return next // Return head of the Policy object linked-list +} + +// A PolicyOptions represents optional information that can be used by a node in the +// linked-list of Policy objects. A PolicyOptions is passed to the Factory's New method +// which passes it (if desired) to the Policy object it creates. Today, the Policy object +// uses the options to perform logging. But, in the future, this could be used for more. +type PolicyOptions struct { + pipeline *pipeline +} + +// ShouldLog returns true if the specified log level should be logged. +func (po *PolicyOptions) ShouldLog(level LogLevel) bool { + if po.pipeline.options.Log.ShouldLog != nil { + return po.pipeline.options.Log.ShouldLog(level) + } + return false +} + +// Log logs a string to the Pipeline's Logger. +func (po *PolicyOptions) Log(level LogLevel, msg string) { + if !po.ShouldLog(level) { + return // Short circuit message formatting if we're not logging it + } + + // We are logging it, ensure trailing newline + if len(msg) == 0 || msg[len(msg)-1] != '\n' { + msg += "\n" // Ensure trailing newline + } + po.pipeline.options.Log.Log(level, msg) + + // If logger doesn't handle fatal/panic, we'll do it here. + if level == LogFatal { + os.Exit(1) + } else if level == LogPanic { + panic(msg) + } +} + +var pipelineHTTPClient = newDefaultHTTPClient() + +func newDefaultHTTPClient() *http.Client { + // We want the Transport to have a large connection pool + return &http.Client{ + Transport: &http.Transport{ + Proxy: http.ProxyFromEnvironment, + // We use Dial instead of DialContext as DialContext has been reported to cause slower performance. + Dial /*Context*/ : (&net.Dialer{ + Timeout: 30 * time.Second, + KeepAlive: 30 * time.Second, + DualStack: true, + }).Dial, /*Context*/ + MaxIdleConns: 0, // No limit + MaxIdleConnsPerHost: 100, + IdleConnTimeout: 90 * time.Second, + TLSHandshakeTimeout: 10 * time.Second, + ExpectContinueTimeout: 1 * time.Second, + DisableKeepAlives: false, + DisableCompression: false, + MaxResponseHeaderBytes: 0, + //ResponseHeaderTimeout: time.Duration{}, + //ExpectContinueTimeout: time.Duration{}, + }, + } +} + +// newDefaultHTTPClientFactory creates a DefaultHTTPClientPolicyFactory object that sends HTTP requests to a Go's default http.Client. +func newDefaultHTTPClientFactory() Factory { + return FactoryFunc(func(next Policy, po *PolicyOptions) PolicyFunc { + return func(ctx context.Context, request Request) (Response, error) { + r, err := pipelineHTTPClient.Do(request.WithContext(ctx)) + if err != nil { + err = NewError(err, "HTTP request failed") + } + return NewHTTPResponse(r), err + } + }) +} + +var mfm = methodFactoryMarker{} // Singleton + +// MethodFactoryMarker returns a special marker Factory object. When Pipeline's Do method is called, any +// MethodMarkerFactory object is replaced with the specified methodFactory object. If nil is passed fro Do's +// methodFactory parameter, then the MethodFactoryMarker is ignored as the linked-list of Policy objects is created. +func MethodFactoryMarker() Factory { + return mfm +} + +type methodFactoryMarker struct { +} + +func (methodFactoryMarker) New(next Policy, po *PolicyOptions) Policy { + panic("methodFactoryMarker policy should have been replaced with a method policy") +} |