Initial commit

1 files changed, 104 insertions, 0 deletions

diff --git a/source.go b/source.go
new file mode 100644
index 0000000..353a225
--- /dev/null
+++ b/source.go
@@ -0,0 +1,104 @@
+package main
+
+import (
+    "strings"
+    "io"
+    "fmt"
+    "os"
+    "context"
+    "net"
+    "net/http"
+)
+
+type Source interface{
+    Get() (MetricFamilies, error)
+}
+
+type textSource interface{
+    textGet() (io.ReadCloser, string, error)
+}
+func sourceGetHelper(self textSource) (MetricFamilies, error){
+    rc, ty, err := self.textGet()
+    if err != nil{
+        return MetricFamilies{},
+            fmt.Errorf("while opening: %w", err)
+    }
+    text, err := io.ReadAll(rc)
+    rc.Close()
+    if err != nil{
+        return MetricFamilies{},
+            fmt.Errorf("while reading: %w", err)
+    }
+    ret, err := ParseMetrics(text, ty)
+    if err != nil{
+        return MetricFamilies{},
+            fmt.Errorf("while parsing: %w", err)
+    }
+    return ret, nil
+}
+
+type FileSource string
+func (self FileSource) Get() (MetricFamilies, error){
+    return sourceGetHelper(self)
+}
+func (self FileSource) textGet() (io.ReadCloser, string, error){
+    f, err := os.Open(string(self))
+    if err != nil{
+        return nil, "", err
+    }
+    return f, "application/openmetrics-text", nil
+}
+
+type HttpSource struct{
+    vurl string
+    client *http.Client
+}
+func NewHttpSource(loc string) (HttpSource, error){
+    return HttpSource{
+        vurl: loc,
+        client: &http.Client{},
+    }, nil
+}
+func NewUnixHttpSource(loc string) (HttpSource, error){
+    colon := strings.Index(loc, ":")
+    if colon < 0 { return HttpSource{}, fmt.Errorf("No protocol part") }
+    if loc[0:colon] != "unix+http"{
+        return HttpSource{}, fmt.Errorf("Invalid protocol")
+    }
+    loc = loc[colon+1:]
+    path := loc
+    domstart := strings.Index(loc, "//")
+    if 0 < domstart{
+        path = loc[0:domstart]
+        if strings.Index(loc[domstart+2:], "/") < 0{
+            loc = "http:" + loc[domstart:] + "/metrics"
+        }else{
+            loc = "http:" + loc[domstart:]
+        }
+    }else{
+        loc = "http://0.0.0.0/metrics"
+    }
+    tp := http.Transport{
+        DialContext: func(c context.Context, _, _ string)(net.Conn, error){
+            return (&net.Dialer{}).DialContext(c, "unix", path)
+        },
+    }
+    return HttpSource{
+        vurl: loc,
+        client: &http.Client{Transport: &tp},
+    }, nil
+}
+func (self HttpSource) Get() (MetricFamilies, error){
+    return sourceGetHelper(self)
+}
+func (self HttpSource) textGet() (io.ReadCloser, string, error){
+    r, err := self.client.Get(self.vurl)
+    if err != nil{
+        return nil, "", err
+    }
+    if r.StatusCode != 200{
+        r.Body.Close()
+        return nil, "", fmt.Errorf("unexpected response: %s", r.Status)
+    }
+    return r.Body, r.Header.Get("Content-Type"), nil
+}