extracting containerId from fargate

Author: Akshay2191

pkg/host/info.go

@@ -9,9 +9,11 @@ import (
 	"bufio"
 	"bytes"
 	"context"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"io"
+	"net/http"
 	"os"
 	"regexp"
 	"strings"
@@ -31,6 +33,8 @@ const (
 	mountInfoLocation  = "/proc/self/mountinfo"
 	osReleaseLocation  = "/etc/os-release"
 
+	ecsMetadataEnvV4 = "ECS_CONTAINER_METADATA_URI_V4"
+
 	k8sKind    = "kubepods"
 	docker     = "docker"
 	containerd = "containerd"
@@ -112,7 +116,20 @@ func (i *Info) IsContainer() (bool, error) {
 		}
 	}
 
-	return containsContainerReference(i.selfCgroupLocation)
+	ref, err := containsContainerReference(i.selfCgroupLocation)
+	if ref {
+		return true, nil
+	}
+
+	if os.Getenv(ecsMetadataEnvV4) != "" {
+		return true, nil
+	}
+
+	if err != nil {
+		return false, err
+	}
+
+	return false, nil
 }
 
 // ResourceID returns a unique identifier for the resource.
@@ -121,7 +138,7 @@ func (i *Info) IsContainer() (bool, error) {
 func (i *Info) ResourceID(ctx context.Context) (string, error) {
 	isContainer, _ := i.IsContainer()
 	if isContainer {
-		return i.containerID()
+		return i.containerID(ctx)
 	}
 
 	return i.hostID(ctx)
@@ -134,7 +151,7 @@ func (i *Info) ContainerInfo(ctx context.Context) (*v1.Resource_ContainerInfo, e
 	if err != nil {
 		return nil, err
 	}
-	containerId, err := i.containerID()
+	containerId, err := i.containerID(ctx)
 	if err != nil {
 		return nil, err
 	}
@@ -203,9 +220,34 @@ func (i *Info) releaseInfo(ctx context.Context, osReleaseLocation string) (*v1.R
 }
 
 // containerID returns the container ID of the current running environment.
-func (i *Info) containerID() (string, error) {
-	containerID, err := containerIDFromMountInfo(i.mountInfoLocation)
-	return uuid.NewMD5(uuid.NameSpaceDNS, []byte(containerID)).String(), err
+func (i *Info) containerID(ctx context.Context) (string, error) {
+	var (
+		containerIDMount string
+		errMount         error
+	)
+
+	containerIDMount, errMount = containerIDFromMountInfo(i.mountInfoLocation)
+	if containerIDMount != "" {
+		return uuid.NewMD5(uuid.NameSpaceDNS, []byte(containerIDMount)).String(), nil
+	}
+
+	if metadataURI := os.Getenv(ecsMetadataEnvV4); metadataURI != "" {
+		if cid, errEcs := i.containerIDFromECS(ctx, metadataURI); errEcs == nil && cid != "" {
+			return uuid.NewMD5(uuid.NameSpaceDNS, []byte(cid)).String(), nil
+		} else if errEcs != nil {
+			if errMount != nil {
+				return "", errMount
+			}
+
+			return "", errEcs
+		}
+	}
+
+	if errMount != nil {
+		return "", errMount
+	}
+
+	return "", errors.New("container ID not found")
 }
 
 // containsContainerReference checks if the cgroup file contains references to container runtimes.
@@ -367,3 +409,30 @@ func mergeHostAndOsReleaseInfo(
 		Id:        osReleaseInfo[id],
 	}
 }
+
+func (i *Info) containerIDFromECS(ctx context.Context, uri string) (string, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, uri, nil)
+	if err != nil {
+		return "", err
+	}
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("metadata endpoint returned status %d", resp.StatusCode)
+	}
+
+	var metadata struct {
+		DockerId string `json:"DockerId"`
+	}
+
+	if err = json.NewDecoder(resp.Body).Decode(&metadata); err != nil {
+		return "", err
+	}
+
+	return metadata.DockerId, nil
+}

pkg/host/info_test.go

@@ -7,6 +7,9 @@ package host
 
 import (
 	"context"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
 	"os"
 	"strings"
 	"testing"
@@ -633,3 +636,55 @@ func TestInfo_ParseOsReleaseFile(t *testing.T) {
 		})
 	}
 }
+
+func TestInfo_containerIDFromECS(t *testing.T) {
+	ctx := context.Background()
+
+	tests := []struct {
+		name      string
+		handler   http.HandlerFunc
+		wantID    string
+		expectErr bool
+	}{
+		{
+			name: "Test 1: success - valid JSON",
+			handler: func(w http.ResponseWriter, r *http.Request) {
+				w.WriteHeader(http.StatusOK)
+				fmt.Fprintln(w, `{"DockerId":"c1234567890"}`)
+			},
+			wantID:    "c1234567890",
+			expectErr: false,
+		},
+		{
+			name: "Test 2: non-200 response",
+			handler: func(w http.ResponseWriter, r *http.Request) {
+				w.WriteHeader(http.StatusInternalServerError)
+			},
+			expectErr: true,
+		},
+		{
+			name: "Test 3: invalid JSON",
+			handler: func(w http.ResponseWriter, r *http.Request) {
+				w.WriteHeader(http.StatusOK)
+				fmt.Fprintln(w, `not-a-json`)
+			},
+			expectErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			srv := httptest.NewServer(tt.handler)
+			defer srv.Close()
+
+			info := NewInfo()
+			id, err := info.containerIDFromECS(ctx, srv.URL)
+			if tt.expectErr {
+				require.Error(t, err)
+			} else {
+				require.NoError(t, err)
+				assert.Equal(t, tt.wantID, id)
+			}
+		})
+	}
+}