gtsocial-umbx

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api_common.go (3666B)

      1 // Copyright 2015 Google Inc. All rights reserved.
      2 // Use of this source code is governed by the Apache 2.0
      3 // license that can be found in the LICENSE file.
      4 
      5 package internal
      6 
      7 import (
      8 	"errors"
      9 	"os"
     10 
     11 	"github.com/golang/protobuf/proto"
     12 	netcontext "golang.org/x/net/context"
     13 )
     14 
     15 var errNotAppEngineContext = errors.New("not an App Engine context")
     16 
     17 type CallOverrideFunc func(ctx netcontext.Context, service, method string, in, out proto.Message) error
     18 
     19 var callOverrideKey = "holds []CallOverrideFunc"
     20 
     21 func WithCallOverride(ctx netcontext.Context, f CallOverrideFunc) netcontext.Context {
     22 	// We avoid appending to any existing call override
     23 	// so we don't risk overwriting a popped stack below.
     24 	var cofs []CallOverrideFunc
     25 	if uf, ok := ctx.Value(&callOverrideKey).([]CallOverrideFunc); ok {
     26 		cofs = append(cofs, uf...)
     27 	}
     28 	cofs = append(cofs, f)
     29 	return netcontext.WithValue(ctx, &callOverrideKey, cofs)
     30 }
     31 
     32 func callOverrideFromContext(ctx netcontext.Context) (CallOverrideFunc, netcontext.Context, bool) {
     33 	cofs, _ := ctx.Value(&callOverrideKey).([]CallOverrideFunc)
     34 	if len(cofs) == 0 {
     35 		return nil, nil, false
     36 	}
     37 	// We found a list of overrides; grab the last, and reconstitute a
     38 	// context that will hide it.
     39 	f := cofs[len(cofs)-1]
     40 	ctx = netcontext.WithValue(ctx, &callOverrideKey, cofs[:len(cofs)-1])
     41 	return f, ctx, true
     42 }
     43 
     44 type logOverrideFunc func(level int64, format string, args ...interface{})
     45 
     46 var logOverrideKey = "holds a logOverrideFunc"
     47 
     48 func WithLogOverride(ctx netcontext.Context, f logOverrideFunc) netcontext.Context {
     49 	return netcontext.WithValue(ctx, &logOverrideKey, f)
     50 }
     51 
     52 var appIDOverrideKey = "holds a string, being the full app ID"
     53 
     54 func WithAppIDOverride(ctx netcontext.Context, appID string) netcontext.Context {
     55 	return netcontext.WithValue(ctx, &appIDOverrideKey, appID)
     56 }
     57 
     58 var namespaceKey = "holds the namespace string"
     59 
     60 func withNamespace(ctx netcontext.Context, ns string) netcontext.Context {
     61 	return netcontext.WithValue(ctx, &namespaceKey, ns)
     62 }
     63 
     64 func NamespaceFromContext(ctx netcontext.Context) string {
     65 	// If there's no namespace, return the empty string.
     66 	ns, _ := ctx.Value(&namespaceKey).(string)
     67 	return ns
     68 }
     69 
     70 // FullyQualifiedAppID returns the fully-qualified application ID.
     71 // This may contain a partition prefix (e.g. "s~" for High Replication apps),
     72 // or a domain prefix (e.g. "example.com:").
     73 func FullyQualifiedAppID(ctx netcontext.Context) string {
     74 	if id, ok := ctx.Value(&appIDOverrideKey).(string); ok {
     75 		return id
     76 	}
     77 	return fullyQualifiedAppID(ctx)
     78 }
     79 
     80 func Logf(ctx netcontext.Context, level int64, format string, args ...interface{}) {
     81 	if f, ok := ctx.Value(&logOverrideKey).(logOverrideFunc); ok {
     82 		f(level, format, args...)
     83 		return
     84 	}
     85 	c := fromContext(ctx)
     86 	if c == nil {
     87 		panic(errNotAppEngineContext)
     88 	}
     89 	logf(c, level, format, args...)
     90 }
     91 
     92 // NamespacedContext wraps a Context to support namespaces.
     93 func NamespacedContext(ctx netcontext.Context, namespace string) netcontext.Context {
     94 	return withNamespace(ctx, namespace)
     95 }
     96 
     97 // SetTestEnv sets the env variables for testing background ticket in Flex.
     98 func SetTestEnv() func() {
     99 	var environ = []struct {
    100 		key, value string
    101 	}{
    102 		{"GAE_LONG_APP_ID", "my-app-id"},
    103 		{"GAE_MINOR_VERSION", "067924799508853122"},
    104 		{"GAE_MODULE_INSTANCE", "0"},
    105 		{"GAE_MODULE_NAME", "default"},
    106 		{"GAE_MODULE_VERSION", "20150612t184001"},
    107 	}
    108 
    109 	for _, v := range environ {
    110 		old := os.Getenv(v.key)
    111 		os.Setenv(v.key, v.value)
    112 		v.value = old
    113 	}
    114 	return func() { // Restore old environment after the test completes.
    115 		for _, v := range environ {
    116 			if v.value == "" {
    117 				os.Unsetenv(v.key)
    118 				continue
    119 			}
    120 			os.Setenv(v.key, v.value)
    121 		}
    122 	}
    123 }