vendor: update all dependencies to latest versions

This commit is contained in:
Nick Craig-Wood 2017-09-30 15:27:27 +01:00
parent 911d121bb9
commit b017fcfe9a
3048 changed files with 537057 additions and 189681 deletions

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# Example
`scan` is an example how to use Amazon DynamoDB's `expression` package to fill
the member fields of Amazon DynamoDB's Operation input types.
## Representing DynamoDB Expressions
In the example, the variable `filt` represents a `FilterExpression`. Note that
DynamoDB item attributes are represented using the function `Name()` and
DynamoDB item values are similarly represented using the function `Value()`. In
this context, the string `"Artist"` represents the name of the item attribute
that we want to evaluate and the string `"No One You Know"` represents the value
we want to evaluate the item attribute against. The relationship between the two
[operands](http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.OperatorsAndFunctions.html#Expressions.OperatorsAndFunctions.Syntax)
are specified using the method `Equal()`.
Similarly, the variable `proj` represents a `ProjectionExpression`. The list of
item attribute names comprising the `ProjectionExpression` are specified as
arguments to the function `NamesList()`. The `expression` package utilizes the
type safety of Go and if an item value were to be used as an argument to the
function `NamesList()`, a compile time error is returned. The pattern of
representing DynamoDB Expressions by indicating relationships between `operands`
with functions is consistent throughout the whole `expression` package.
```go
filt := expression.Name("Artist").Equal(expression.Value("No One You Know"))
// let :a be an ExpressionAttributeValue representing the string "No One You Know"
// equivalent FilterExpression: "Artist = :a"
proj := expression.NamesList(expression.Name("SongTitle"), expression.Name("AlbumTitle"))
// equivalent ProjectionExpression: "SongTitle, AlbumTitle"
```
## Creating an `Expression`
In the example, the variable `expr` is an instance of an `Expression` type. An
`Expression` is built using a builder pattern. First, a new `Builder` is
initialized by the `NewBuilder()` function. Then, types representing DynamoDB
Expressions are added to the `Builder` by methods `WithFilter()` and
`WithProjection()`. The `Build()` method returns an instance of an `Expression`
and an error. The error will be either an `InvalidParameterError` or an
`UnsetParameterError`.
```go
filt := expression.Name("Artist").Equal(expression.Value("No One You Know"))
proj := expression.NamesList(expression.Name("SongTitle"), expression.Name("AlbumTitle"))
expr, err := expression.NewBuilder().WithFilter(filt).WithProjection(proj).Build()
if err != nil {
fmt.Println(err)
}
```
## Filling in the fields of a DynamoDB `Scan` API
In the example, the getter methods of the `Expression` type is used to get the
formatted DynamoDB Expression strings. The `ExpressionAttributeNames` and
`ExpressionAttributeValues` member field of the DynamoDB API must always be
assigned when using an `Expression` since all item attribute names and values
are aliased. That means that if the `ExpressionAttributeNames` and
`ExpressionAttributeValues` member is not assigned with the corresponding
`Names()` and `Values()` methods, the DynamoDB operation will run into a logic
error.
```go
filt := expression.Name("Artist").Equal(expression.Value("No One You Know"))
proj := expression.NamesList(expression.Name("SongTitle"), expression.Name("AlbumTitle"))
expr, err := expression.NewBuilder().WithFilter(filt).WithProjection(proj).Build()
if err != nil {
fmt.Println(err)
}
input := &dynamodb.ScanInput{
ExpressionAttributeNames: expr.Names(),
ExpressionAttributeValues: expr.Values(),
FilterExpression: expr.Filter(),
ProjectionExpression: expr.Projection(),
TableName: aws.String("Music"),
}
```
## Usage
`go run -tags example scan.go -table "<table_name>" -region "<optional_region>"`
## Output
```
{
Count: #SomeNumber,
Items: [{
AlbumTitle: {
#SomeAlbumTitle
},
SongTitle: {
#SomeSongTitle
}
}],
...
ScannedCount: #SomeNumber,
}
```

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// +build example
package main
import (
"flag"
"fmt"
"os"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/session"
"github.com/aws/aws-sdk-go/service/dynamodb"
"github.com/aws/aws-sdk-go/service/dynamodb/expression"
)
func exitWithError(err error) {
fmt.Fprintln(os.Stderr, err)
os.Exit(1)
}
func main() {
cfg := Config{}
if err := cfg.Load(); err != nil {
exitWithError(fmt.Errorf("failed to load config, %v", err))
}
// Create the config specifying the Region for the DynamoDB table.
// If Config.Region is not set the region must come from the shared
// config or AWS_REGION environment variable.
awscfg := &aws.Config{}
if len(cfg.Region) > 0 {
awscfg.WithRegion(cfg.Region)
}
// Create the session that the DynamoDB service will use.
sess := session.Must(session.NewSession(awscfg))
// Create the DynamoDB service client to make the query request with.
svc := dynamodb.New(sess)
// Create the Expression to fill the input struct with.
filt := expression.Name("Artist").Equal(expression.Value("No One You Know"))
proj := expression.NamesList(expression.Name("SongTitle"), expression.Name("AlbumTitle"))
expr, err := expression.NewBuilder().WithFilter(filt).WithProjection(proj).Build()
if err != nil {
exitWithError(fmt.Errorf("failed to create the Expression, %v", err))
}
// Build the query input parameters
params := &dynamodb.ScanInput{
ExpressionAttributeNames: expr.Names(),
ExpressionAttributeValues: expr.Values(),
FilterExpression: expr.Filter(),
ProjectionExpression: expr.Projection(),
TableName: aws.String(cfg.Table),
}
if cfg.Limit > 0 {
params.Limit = aws.Int64(cfg.Limit)
}
// Make the DynamoDB Query API call
result, err := svc.Scan(params)
if err != nil {
exitWithError(fmt.Errorf("failed to make Query API call, %v", err))
}
fmt.Println(result)
}
type Config struct {
Table string // required
Region string // optional
Limit int64 // optional
}
func (c *Config) Load() error {
flag.Int64Var(&c.Limit, "limit", 0, "Limit is the max items to be returned, 0 is no limit")
flag.StringVar(&c.Table, "table", "", "Table to Query on")
flag.StringVar(&c.Region, "region", "", "AWS Region the table is in")
flag.Parse()
if len(c.Table) == 0 {
flag.PrintDefaults()
return fmt.Errorf("table name is required.")
}
return nil
}

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# Example Fetch By region
This is an example using the AWS SDK for Go to list ec2 instances instance state By different region . By default it fetch all running and stopped instance
# Usage
```sh
# To fetch the stopped instance of all region use below:
./filter_ec2_by_region --state running --state stopped
# To fetch the stopped and running instance for region us-west-1 and eu-west-1 use below:
./filter_ec2_by_region --state running --state stopped --region us-west-1 --region=eu-west-1
```
## Sample Output
```
Fetching instace details for region: ap-south-1 with criteria: [running][stopped]**
printing instance details.....
instance id i-************
current State stopped
done for region ap-south-1 ****
Fetching instace details for region: eu-west-2 with criteria: [running][stopped]**
There is no instance for the for region eu-west-2 with the matching Criteria: [running][stopped]
done for region eu-west-2 ****
```

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// +build example
package main
import (
"flag"
"fmt"
"os"
"strings"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/session"
"github.com/aws/aws-sdk-go/service/ec2"
)
// Prints a list of instances for each region. If no regions are provided
// all regions will be searched. The state is required.
//
// Will use the AWS SDK for Go's default credential chain and region. You can
// specify the region with the AWS_REGION environment variable.
//
// Usage: instancesByRegion -state <value> [-state val...] [-region region...]
func main() {
states, regions := parseArguments()
if len(states) == 0 {
fmt.Fprintf(os.Stderr, "error: %v\n", usage())
os.Exit(1)
}
instanceCriteria := " "
for _, state := range states {
instanceCriteria += "[" + state + "]"
}
if len(regions) == 0 {
var err error
regions, err = fetchRegion()
if err != nil {
fmt.Fprintf(os.Stderr, "error: %v\n", err)
os.Exit(1)
}
}
for _, region := range regions {
sess := session.Must(session.NewSession(&aws.Config{
Region: aws.String(region),
}))
ec2Svc := ec2.New(sess)
params := &ec2.DescribeInstancesInput{
Filters: []*ec2.Filter{
&ec2.Filter{
Name: aws.String("instance-state-name"),
Values: aws.StringSlice(states),
},
},
}
result, err := ec2Svc.DescribeInstances(params)
if err != nil {
fmt.Println("Error", err)
} else {
fmt.Printf("\n\n\nFetching instace details for region: %s with criteria: %s**\n ", region, instanceCriteria)
if len(result.Reservations) == 0 {
fmt.Printf("There is no instance for the for region %s with the matching Criteria:%s \n", region, instanceCriteria)
}
for _, reservation := range result.Reservations {
fmt.Println("printing instance details.....")
for _, instance := range reservation.Instances {
fmt.Println("instance id " + *instance.InstanceId)
fmt.Println("current State " + *instance.State.Name)
}
}
fmt.Printf("done for region %s **** \n", region)
}
}
}
func fetchRegion() ([]string, error) {
awsSession := session.Must(session.NewSession(&aws.Config{}))
svc := ec2.New(awsSession)
awsRegions, err := svc.DescribeRegions(&ec2.DescribeRegionsInput{})
if err != nil {
return nil, err
}
regions := make([]string, 0, len(awsRegions.Regions))
for _, region := range awsRegions.Regions {
regions = append(regions, *region.RegionName)
}
return regions, nil
}
type flagArgs []string
func (a flagArgs) String() string {
return strings.Join(a.Args(), ",")
}
func (a *flagArgs) Set(value string) error {
*a = append(*a, value)
return nil
}
func (a flagArgs) Args() []string {
return []string(a)
}
func parseArguments() (states []string, regions []string) {
var stateArgs, regionArgs flagArgs
flag.Var(&stateArgs, "state", "state list")
flag.Var(&regionArgs, "region", "region list")
flag.Parse()
if flag.NFlag() != 0 {
states = append([]string{}, stateArgs.Args()...)
regions = append([]string{}, regionArgs.Args()...)
}
return states, regions
}
func usage() string {
return `
Missing mandatory flag 'state'. Please use like below Example:
To fetch the stopped instance of all region use below:
./filter_ec2_by_region -state running -state stopped
To fetch the stopped and running instance for region us-west-1 and eu-west-1 use below:
./filter_ec2_by_region -state running -state stopped -region us-west-1 -region=eu-west-1
`
}