Add awsutils to deal with AWS specific things

base/go/awsutils/BUILD

@@ -0,0 +1,13 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "awsutils",
+    srcs = ["config.go"],
+    importpath = "go.resf.org/peridot/base/go/awsutils",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//vendor/github.com/aws/aws-sdk-go/aws",
+        "//vendor/github.com/aws/aws-sdk-go/aws/credentials",
+        "//vendor/github.com/aws/aws-sdk-go/aws/endpoints",
+    ],
+)

base/go/awsutils/config.go

@@ -0,0 +1,73 @@
+package awsutils
+
+import (
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/credentials"
+	"github.com/aws/aws-sdk-go/aws/endpoints"
+	"os"
+)
+
+// FillOutConfig fills out the config with the default values.
+// Supports AWS CLI related environment variables.
+func FillOutConfig(cfg *aws.Config) {
+	// RESF defaults to region us-east-2
+	if cfg.Region == nil || *cfg.Region == "" {
+		region := "us-east-2"
+		if envRegion := os.Getenv("AWS_REGION"); envRegion != "" {
+			region = envRegion
+		}
+		cfg.Region = aws.String(region)
+	}
+
+	// Default to AWS S3 endpoint
+	if cfg.Endpoint == nil || *cfg.Endpoint == "" {
+		if envEndpoint := os.Getenv("AWS_ENDPOINT"); envEndpoint != "" {
+			cfg.Endpoint = aws.String(envEndpoint)
+		}
+	}
+
+	// By default, only connect securely
+	if cfg.DisableSSL == nil {
+		// But allow disabling it
+		if envDisableSSL := os.Getenv("AWS_DISABLE_SSL"); envDisableSSL != "" {
+			cfg.DisableSSL = aws.Bool(envDisableSSL == "true")
+		} else {
+			cfg.DisableSSL = aws.Bool(false)
+		}
+	}
+
+	// By default, do not use path style
+	if cfg.S3ForcePathStyle == nil {
+		// But allow enabling it
+		if envS3ForcePathStyle := os.Getenv("AWS_S3_FORCE_PATH_STYLE"); envS3ForcePathStyle != "" {
+			cfg.S3ForcePathStyle = aws.Bool(envS3ForcePathStyle == "true")
+		} else {
+			cfg.S3ForcePathStyle = aws.Bool(false)
+		}
+	}
+
+	// By default, use dualstack
+	if cfg.UseDualStackEndpoint == endpoints.DualStackEndpointStateUnset {
+		// But allow disabling it
+		if envUseDualStackEndpoint := os.Getenv("AWS_USE_DUALSTACK_ENDPOINT"); envUseDualStackEndpoint != "" {
+			if envUseDualStackEndpoint == "false" {
+				cfg.UseDualStackEndpoint = endpoints.DualStackEndpointStateDisabled
+			} else {
+				cfg.UseDualStackEndpoint = endpoints.DualStackEndpointStateEnabled
+			}
+		} else {
+			cfg.UseDualStackEndpoint = endpoints.DualStackEndpointStateEnabled
+		}
+	}
+
+	// Allow setting access key and secret key with environment variables
+	if cfg.Credentials == nil {
+		// Make sure both ACCESS_KEY_ID and SECRET_ACCESS_KEY are set
+		// Otherwise, do not set credentials
+		envAccessKeyID := os.Getenv("AWS_ACCESS_KEY_ID")
+		envSecretAccessKey := os.Getenv("AWS_SECRET_ACCESS_KEY")
+		if envAccessKeyID != "" && envSecretAccessKey != "" {
+			cfg.Credentials = credentials.NewStaticCredentials(envAccessKeyID, envSecretAccessKey, "")
+		}
+	}
+}