Support multiple JWTs

[keeganwitt]

Something I missed when reviewing #85 is that if you need multiple JWT paths because you have JWTs for more than one audience, there's no way to do this currently.

[faisal-memon]

@keeganwitt How would that work? An array of audiences? Save them in the same or different files?

[keeganwitt]

@keeganwitt How would that work? An array of audiences? Save them in the same or different files?

Yes, an array of files and audiences is what I was thinking. Something like

Index: pkg/sidecar/config.go
===================================================================
diff --git a/pkg/sidecar/config.go b/pkg/sidecar/config.go
--- a/pkg/sidecar/config.go (revision c86aaa3c6aebb44c8296b9caa742f5250703a9ad)
+++ b/pkg/sidecar/config.go (date 1702493092224)
@@ -32,9 +32,10 @@
    RenewSignalDeprecated              string `hcl:"renewSignal"`

    // JWT configuration
-   JWTAudience       string `hcl:"jwt_audience"`
-   JWTSvidFilename   string `hcl:"jwt_svid_file_name"`
-   JWTBundleFilename string `hcl:"jwt_bundle_file_name"`
+   Jwts              []JwtConfig `hcl:"jwts"`
+   JWTAudience       string      `hcl:"jwt_audience"`
+   JWTSvidFilename   string      `hcl:"jwt_svid_file_name"`
+   JWTBundleFilename string      `hcl:"jwt_bundle_file_name"`

    // TODO: is there a reason for this to be exposed? and inside of config?
    ReloadExternalProcess func() error
@@ -42,6 +43,11 @@
    Log logrus.FieldLogger
 }

+type JwtConfig struct {
+   JWTAudience     string `hcl:"jwt_audience"`
+   JWTSvidFilename string `hcl:"jwt_svid_file_name"`
+}
+
 // ParseConfig parses the given HCL file into a SidecarConfig struct
 func ParseConfig(file string) (*Config, error) {
    sidecarConfig := new(Config)

[faisal-memon]

I think we can simplify with just the array of audiences and then add the audience as a suffix to the outputted file.