start refactoring a bit. create a separate package for getting public ip with tests.

Author: dan-v

go.mod

@@ -15,10 +15,13 @@ require (
 	github.com/onsi/ginkgo v1.12.0 // indirect
 	github.com/onsi/gomega v1.9.0 // indirect
 	github.com/pkg/errors v0.9.1
+	github.com/sirupsen/logrus v1.2.0
 	github.com/spf13/cobra v1.0.0
 	github.com/spf13/viper v1.6.3
+	github.com/stretchr/testify v1.5.1
 	golang.org/x/crypto v0.0.0-20200414173820-0848c9571904
 	golang.org/x/lint v0.0.0-20200302205851-738671d3881b // indirect
+	golang.org/x/text v0.3.2 // indirect
 	gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f // indirect
 	gopkg.in/ini.v1 v1.55.0 // indirect
 )

go.sum

@@ -128,6 +128,7 @@ github.com/klauspost/cpuid v1.2.0 h1:NMpwD2G9JSFOE1/TJjGSo5zG7Yb2bTe7eq1jH+irmeE
 github.com/klauspost/cpuid v1.2.0/go.mod h1:Pj4uuM528wm8OyEC2QMXAi2YiTZ96dNQPGgoMS4s3ek=
 github.com/klauspost/reedsolomon v1.7.0 h1:pLFmRKGko2ZieiTGyo9DahLCIuljyxm+Zzhz/fYEonE=
 github.com/klauspost/reedsolomon v1.7.0/go.mod h1:CwCi+NUr9pqSVktrkN+Ondf06rkhYZ/pcNv7fu+8Un4=
+github.com/konsorten/go-windows-terminal-sequences v1.0.1 h1:mweAR1A6xJ3oS2pRaGiHgQ4OO8tzTaLawm8vnODuwDk=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
 github.com/kr/logfmt v0.0.0-20140226030751-b84e30acd515/go.mod h1:+0opPa2QZZtGFBFZlji/RkVcI2GknAs/DXo4wKdlNEc=
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
@@ -195,6 +196,7 @@ github.com/shadowsocks/go-shadowsocks2 v0.1.0/go.mod h1:/0aFGbhK8mtOX4J/6kTJsPLZ
 github.com/shadowsocks/shadowsocks-go v0.0.0-20170121203516-97a5c71f80ba h1:tJgNXb3S+RkB4kNPi6N5OmEWe3m+Y3Qs6LUMiNDAONM=
 github.com/shadowsocks/shadowsocks-go v0.0.0-20170121203516-97a5c71f80ba/go.mod h1:mttDPaeLm87u74HMrP+n2tugXvIKWcwff/cqSX0lehY=
 github.com/shurcooL/sanitized_anchor_name v1.0.0/go.mod h1:1NzhyTcUVG4SuEtjjoZeVRXNmyL/1OwPU0+IJeTBvfc=
+github.com/sirupsen/logrus v1.2.0 h1:juTguoYk5qI21pwyTXY3B3Y5cOTH3ZUyZCg1v/mihuo=
 github.com/sirupsen/logrus v1.2.0/go.mod h1:LxeOpSwHxABJmUn/MG1IvRgCAasNZTLOkJPxbbu5VWo=
 github.com/smartystreets/assertions v0.0.0-20180927180507-b2de0cb4f26d h1:zE9ykElWQ6/NYmHa3jpm/yHnI4xSofP+UP6SpjHcSeM=
 github.com/smartystreets/assertions v0.0.0-20180927180507-b2de0cb4f26d/go.mod h1:OnSkiWE9lh6wB0YB77sQom3nweQdgAjqCqsofrRNTgc=
@@ -292,8 +294,11 @@ golang.org/x/sys v0.0.0-20191120155948-bd437916bb0e h1:N7DeIrjYszNmSW409R3frPPwg
 golang.org/x/sys v0.0.0-20191120155948-bd437916bb0e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
+golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/time v0.0.0-20190308202827-9d24e82272b4/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/tools v0.0.0-20180221164845-07fd8470d635/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190114222345-bf090417da8b/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
 golang.org/x/tools v0.0.0-20190328211700-ab21143f2384/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=

pkg/server/publicip/awspublicip/awspublicip.go

@@ -0,0 +1,54 @@
+package awspublicip
+
+import (
+	"bytes"
+	"fmt"
+	"github.com/dan-v/awslambdaproxy/pkg/server/publicip"
+	"io/ioutil"
+	"net"
+	"net/http"
+	"time"
+)
+
+const (
+	DefaultHTTPTimeout = time.Second * 10
+	AWSProviderURL     = "http://checkip.amazonaws.com/"
+)
+
+type PublicIPClient struct {
+	providerURL string
+	httpClient  *http.Client
+}
+
+func New() *PublicIPClient {
+	return &PublicIPClient{
+		providerURL: AWSProviderURL,
+		httpClient: &http.Client{
+			Timeout: DefaultHTTPTimeout,
+		},
+	}
+}
+
+func (p *PublicIPClient) GetIP() (string, error) {
+	resp, err := p.httpClient.Get(p.providerURL)
+	if err != nil {
+		return "", fmt.Errorf("http request to get ip address from %v failed: %w", p.providerURL, err)
+	}
+	defer resp.Body.Close()
+
+	buf, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return "", fmt.Errorf("reading response body from %v failed: %w", p.providerURL, err)
+	}
+
+	ip := string(bytes.TrimSpace(buf))
+	if net.ParseIP(ip) == nil {
+		return "", fmt.Errorf("unable to parse ip %v: %w",
+			publicip.ErrInvalidIPAddress, publicip.ErrInvalidIPAddress)
+	}
+	return ip, nil
+}
+
+func (p *PublicIPClient) ProviderURL() string {
+	return p.providerURL
+}

pkg/server/publicip/awspublicip/awspublicip_test.go

@@ -0,0 +1,93 @@
+package awspublicip
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"github.com/dan-v/awslambdaproxy/pkg/server/publicip"
+	"github.com/stretchr/testify/assert"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+)
+
+func TestPublicIPClient_GetIP(t *testing.T) {
+	tests := []struct {
+		name     string
+		handler  func(w http.ResponseWriter, r *http.Request)
+		expected string
+		error    error
+	}{
+		{
+			name: "valid ip address returns as expected",
+			handler: func(w http.ResponseWriter, r *http.Request) {
+				fmt.Fprintln(w, "1.1.1.1")
+			},
+			expected: "1.1.1.1",
+			error:    nil,
+		},
+		{
+			name: "valid ip address with padding returns trimmed",
+			handler: func(w http.ResponseWriter, r *http.Request) {
+				fmt.Fprintln(w, "    1.1.1.1     ")
+			},
+			expected: "1.1.1.1",
+			error:    nil,
+		},
+		{
+			name: "invalid ip results in error",
+			handler: func(w http.ResponseWriter, r *http.Request) {
+				fmt.Fprintln(w, "invalid")
+			},
+			expected: "",
+			error:    publicip.ErrInvalidIPAddress,
+		},
+		{
+			name: "empty response results in error",
+			handler: func(w http.ResponseWriter, r *http.Request) {
+				fmt.Fprintln(w, "")
+			},
+			expected: "",
+			error:    publicip.ErrInvalidIPAddress,
+		},
+		{
+			name: "server timeout causes deadline exceeded error",
+			handler: func(w http.ResponseWriter, r *http.Request) {
+				time.Sleep(20 * time.Millisecond)
+			},
+			expected: "",
+			error:    context.DeadlineExceeded,
+		},
+		{
+			name: "invalid content length causes body read error",
+			handler: func(w http.ResponseWriter, r *http.Request) {
+				w.Header().Set("Content-Length", "1")
+			},
+			expected: "",
+			error:    errors.New("unexpected EOF"),
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ts := httptest.NewServer(http.HandlerFunc(tt.handler))
+			defer ts.Close()
+
+			p := New()
+			p.providerURL = ts.URL
+			p.httpClient.Timeout = time.Millisecond * 10
+			ip, err := p.GetIP()
+			if tt.error != nil {
+				assert.Contains(t, errors.Unwrap(err).Error(), tt.error.Error())
+			} else {
+				assert.NoError(t, err)
+			}
+			assert.Equal(t, tt.expected, ip)
+		})
+	}
+}
+
+func TestPublicIPClient_ProviderURL(t *testing.T) {
+	p := New()
+	assert.Equal(t, AWSProviderURL, p.ProviderURL())
+}