fix(config): skip api. prefix for on-call domains in DD_SITE

On-call domains like navy.oncall.datadoghq.com are already
fully-qualified API endpoints. Previously, pup always prepended "api."
to DD_SITE, resulting in invalid URLs like
api.navy.oncall.datadoghq.com.

Now, when DD_SITE contains "oncall", the domain is used as-is for both
the API client host and RawRequest URLs.

Closes #66

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: platinummonkey

pkg/client/client.go

@@ -105,7 +105,7 @@ func NewWithOptions(cfg *config.Config, forceAPIKeys bool) (*Client, error) {
 
 	// Configure the API client
 	configuration := datadog.NewConfiguration()
-	configuration.Host = fmt.Sprintf("api.%s", cfg.Site)
+	configuration.Host = cfg.GetAPIHost()
 
 	// Set custom user agent to identify requests as coming from pup CLI
 	configuration.UserAgent = useragent.Get()
@@ -175,7 +175,7 @@ func (c *Client) RawRequest(method, path string, body io.Reader) (*http.Response
 		return nil, err
 	}
 
-	url := fmt.Sprintf("https://api.%s%s", c.config.Site, path)
+	url := fmt.Sprintf("https://%s%s", c.config.GetAPIHost(), path)
 
 	req, err := http.NewRequest(method, url, body)
 	if err != nil {

pkg/config/config.go

@@ -8,6 +8,7 @@ package config
 import (
 	"fmt"
 	"os"
+	"strings"
 )
 
 // Config holds the application configuration
@@ -41,9 +42,26 @@ func (c *Config) Validate() error {
 	return nil
 }
 
-// GetAPIURL returns the full API URL for the configured site
+// IsOnCallSite returns true if the site is an on-call domain (contains "oncall").
+// On-call domains like navy.oncall.datadoghq.com are already fully-qualified
+// and should not have "api." prepended.
+func IsOnCallSite(site string) bool {
+	return strings.Contains(site, "oncall")
+}
+
+// GetAPIURL returns the full API URL for the configured site.
+// On-call domains are used as-is; all other sites get "https://api.{site}".
 func (c *Config) GetAPIURL() string {
-	return fmt.Sprintf("https://api.%s", c.Site)
+	return "https://" + c.GetAPIHost()
+}
+
+// GetAPIHost returns the host portion of the API URL (without scheme).
+// On-call domains are returned as-is; all other sites get "api.{site}".
+func (c *Config) GetAPIHost() string {
+	if IsOnCallSite(c.Site) {
+		return c.Site
+	}
+	return fmt.Sprintf("api.%s", c.Site)
 }
 
 // getEnvWithDefault returns environment variable value or default if not set

pkg/config/config_test.go

@@ -82,6 +82,17 @@ func TestLoad(t *testing.T) {
 			wantSite:    "datadoghq.com",
 			wantApprove: false,
 		},
+		{
+			name: "on-call domain via DD_SITE",
+			envVars: map[string]string{
+				"DD_API_KEY": "key",
+				"DD_APP_KEY": "app",
+				"DD_SITE":    "navy.oncall.datadoghq.com",
+			},
+			wantAPIKey: "key",
+			wantAppKey: "app",
+			wantSite:   "navy.oncall.datadoghq.com",
+		},
 	}
 
 	for _, tt := range tests {
@@ -176,6 +187,36 @@ func TestConfig_Validate(t *testing.T) {
 	}
 }
 
+func TestIsOnCallSite(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		name string
+		site string
+		want bool
+	}{
+		// Standard sites — not on-call
+		{name: "US1", site: "datadoghq.com", want: false},
+		{name: "EU", site: "datadoghq.eu", want: false},
+		{name: "US3", site: "us3.datadoghq.com", want: false},
+		{name: "Gov", site: "ddog-gov.com", want: false},
+
+		// On-call domains
+		{name: "on-call navy", site: "navy.oncall.datadoghq.com", want: true},
+		{name: "on-call army", site: "army.oncall.datadoghq.com", want: true},
+		{name: "on-call staging", site: "test.oncall.datad0g.com", want: true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			got := IsOnCallSite(tt.site)
+			if got != tt.want {
+				t.Errorf("IsOnCallSite(%q) = %v, want %v", tt.site, got, tt.want)
+			}
+		})
+	}
+}
+
 func TestConfig_GetAPIURL(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
@@ -218,6 +259,11 @@ func TestConfig_GetAPIURL(t *testing.T) {
 			site: "datad0g.com",
 			want: "https://api.datad0g.com",
 		},
+		{
+			name: "on-call domain used as-is",
+			site: "navy.oncall.datadoghq.com",
+			want: "https://navy.oncall.datadoghq.com",
+		},
 	}
 
 	for _, tt := range tests {
@@ -232,6 +278,32 @@ func TestConfig_GetAPIURL(t *testing.T) {
 	}
 }
 
+func TestConfig_GetAPIHost(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		name string
+		site string
+		want string
+	}{
+		{name: "US1", site: "datadoghq.com", want: "api.datadoghq.com"},
+		{name: "EU", site: "datadoghq.eu", want: "api.datadoghq.eu"},
+		{name: "US3", site: "us3.datadoghq.com", want: "api.us3.datadoghq.com"},
+		{name: "Gov", site: "ddog-gov.com", want: "api.ddog-gov.com"},
+		{name: "on-call", site: "navy.oncall.datadoghq.com", want: "navy.oncall.datadoghq.com"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			cfg := &Config{Site: tt.site}
+			got := cfg.GetAPIHost()
+			if got != tt.want {
+				t.Errorf("GetAPIHost() = %q, want %q", got, tt.want)
+			}
+		})
+	}
+}
+
 func TestGetEnvWithDefault(t *testing.T) {
 	t.Parallel()
 	// Save original