openshift_secondary_metadata_parser: Add 'version' parsing

Consuming the 'version' file that graph-data grew in [1], so the logs
will contain more useful error messages when the plugin is fed an
incompatible schema version.

Bumping the graph-data commit used for CI moves us to the first
main-line commit to include the 'version' file:

  cincinnati-graph-data$ git --no-pager show --date=short --format='%ad %h %s' d980578d2e b87e7c2782
  2020-03-18 d980578 Merge pull request openshift#125 from marun/unique-service-ca-serial

  2020-05-11 b87e7c2 Merge pull request openshift#233 from wking/version-file

[1]: openshift/cincinnati-graph-data#233

cincinnati/src/plugins/internal/graph_builder/github_openshift_secondary_metadata_scraper/plugin.rs

@@ -9,6 +9,7 @@ use self::cincinnati::plugins::prelude_plugin_impl::*;
 use tokio::sync::Mutex as FuturesMutex;
 
 pub static DEFAULT_OUTPUT_WHITELIST: &[&str] = &[
+    "version",
     "channels/.+\\.ya+ml",
     "blocked-edges/.+\\.ya+ml",
     "raw/metadata.json",

cincinnati/src/plugins/internal/graph_builder/openshift_secondary_metadata_parser/plugin.rs

@@ -7,6 +7,7 @@ use self::cincinnati::plugins::prelude_plugin_impl::*;
 use std::collections::HashSet;
 
 pub static DEFAULT_KEY_FILTER: &str = "io.openshift.upgrades.graph";
+static SUPPORTED_VERSIONS: &[&str] = &["1.0.0"];
 
 pub mod graph_data_model {
     //! This module contains the data types corresponding to the graph data files.
@@ -295,6 +296,24 @@ impl OpenshiftSecondaryMetadataParserPlugin {
         }
     }
 
+    async fn process_version(&self, data_dir: &PathBuf) -> Fallible<String> {
+        let path = data_dir.join("version");
+        let version = tokio::fs::read(&path)
+            .await
+            .context(format!("Reading {:?}", &path))?;
+        let string_version = String::from_utf8_lossy(&version);
+
+        if SUPPORTED_VERSIONS.contains(&string_version.trim()) {
+            Ok(string_version.into_owned())
+        } else {
+            Err(format_err!(
+                "unrecognized graph-data version {}; supported versions: {:?}",
+                string_version,
+                SUPPORTED_VERSIONS
+            ))
+        }
+    }
+
     async fn process_raw_metadata(
         &self,
         graph: &mut cincinnati::Graph,
@@ -563,6 +582,7 @@ impl InternalPlugin for OpenshiftSecondaryMetadataParserPlugin {
     async fn run_internal(self: &Self, mut io: InternalIO) -> Fallible<InternalIO> {
         let data_dir = self.get_data_directory(&io);
 
+        self.process_version(&data_dir).await?;
         self.process_raw_metadata(&mut io.graph, &data_dir).await?;
         self.process_blocked_edges(&mut io.graph, &data_dir).await?;
         self.process_channels(&mut io.graph, &data_dir).await?;

cincinnati/src/plugins/internal/graph_builder/openshift_secondary_metadata_parser/test_fixtures/20200220.104838/cincinnati-graph-data/version

@@ -0,0 +1 @@
+1.0.0

cincinnati/src/plugins/internal/graph_builder/openshift_secondary_metadata_parser/test_fixtures/20200319.204124/cincinnati-graph-data/version

@@ -0,0 +1 @@
+1.0.0

cincinnati/src/plugins/internal/graph_builder/openshift_secondary_metadata_parser/test_fixtures/invalid0/cincinnati-graph-data/version

@@ -0,0 +1 @@
+1.0.0